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Journal logoSTRUCTURAL SCIENCE
CRYSTAL ENGINEERING
MATERIALS
ISSN: 2052-5206
Volume 76| Part 6| December 2020| Pages 979-991
https://doi.org/10.1107/S205252062001238X

Pressure-induced Pb–Pb bonding and phase transition in Pb2SnO4

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Dominik Spahr,a* Michał Stękiel,a Dominik Zimmer,a Lkhamsuren Bayarjargal,a Katja Bunk,a Wolfgang Morgenroth,a Victor Milman,b Keith Refson,c Dominik Jochym,d Peter J. P. Byrnee and Björn Winklera

aGoethe University, Institute of Geosciences, Crystallography, Frankfurt, Germany, bDassault Systèmes BIOVIA, Cambridge, United Kingdom, cRoyal Holloway, University of London, Physics, Oxford, United Kingdom, dScientific Computing Department, Rutherford Appleton Laboratory, Oxford, United Kingdom, and eUniversity of York, Physics, Heslington, United Kingdom
*Correspondence e-mail: d.spahr@kristall.uni-frankfurt.de

Edited by A. Katrusiak, Adam Mickiewicz University, Poland (Received 7 July 2020; accepted 8 September 2020; online 3 November 2020)

High-pressure single-crystal to 20 GPa and powder diffraction measurements to 50 GPa, show that the structure of Pb2SnO4 strongly distorts on compression with an elongation of one axis. A structural phase transition occurs between 10 GPa and 12 GPa, with a change of space group from Pbam to Pnam. The resistivity decreases by more than six orders of magnitude when pressure is increased from ambient conditions to 50 GPa. This insulator-to-semiconductor transition is accompanied by a reversible appearance change from transparent to opaque. Density functional theory-based calculations show that at ambient conditions the channels in the structure host the stereochemically-active Pb 6s2 lone electron pairs. On compression the lone electron pairs form bonds between Pb2+ ions. Also provided is an assignment of irreducible representations to the experimentally observed Raman bands.

CCDC references: 2030954; 2030955; 2030956; 2030957; 2030958; 2030959; 2030960; 2030961; 2030962

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1. Introduction

Lead stannate (Pb2SnO4) belongs to a family of stannates with composition M2SnO4, where M2+ = Mg, Mn, Ca, Ba, Sr, Pb. Characteristic for these stannates is that the SnO6 octahedra either form layers by sharing corners in a plane (as in Ba2SnO4 and isostructural Sr2SnO4) or chains by sharing edges (as in Ca2SnO4 and Pb2SnO4). They represent a fascinating class of compounds and have been studied extensively as they may be suitable for a variety of applications, e.g. as photocatalysts (Qin et al., 2015[Qin, Y., Xiong, J., Zhang, W., Liu, L., Cui, Y. & Gu, H. (2015). J. Mater. Sci. 50, 5865-5872.]; Dinesh et al., 2016[Dinesh, S., Barathan, S., Premkumar, V. K., Sivakumar, G. & Anandan, N. (2016). J. Mater. Sci. Mater. Electron. 27, 9668-9675.]), as electrode material for Li-ion batteries (Rong et al., 2006[Rong, A., Gao, X. P., Li, G., Yan, T. Y., Zhu, H., Qu, J. Q. & Song, D. Y. (2006). J. Phys. Chem. B, 110, 14754-14760.]; Liang et al., 2016[Liang, K., Cheang, T.-Y., Wen, T., Xie, X., Zhou, X., Zhao, Z.-W., Shen, C.-C., Jiang, N. & Xu, A.-W. (2016). J. Phys. Chem. C, 120, 3669-3676.]) or as anode-material in solar cells (Tan et al., 2007[Tan, B., Toman, E., Li, Y. & Wu, Y. (2007). J. Am. Chem. Soc. 129, 4162-4163.]). Furthermore, stannates doped with rare earth elements, such as Eu, Y, Sm, have been extensively investigated regarding their use as long afterglow phosphors (Chen et al., 2005a[Chen, Y.-C., Chang, Y.-H. & Tsai, B.-S. (2005a). J. Alloys Compd. 398, 256-260.],b[Chen, Y.-C., Chang, Y.-H. & Tsai, B.-S. (2005b). Opt. Mater. 27, 1874-1878.]; Yang et al., 2005[Yang, H. M., Shi, J. X. & Gong, M. L. (2005). J. Solid State Chem. 178, 917-920.]; Yamane et al., 2008[Yamane, H., Kaminaga, Y., Abe, S. & Yamada, T. (2008). J. Solid State Chem. 181, 2559-2564.]; Zhang et al., 2010[Zhang, J., Yu, M., Qin, Q., Zhou, H., Zhou, M., Xu, X. & Wang, Y. (2010). J. Appl. Phys. 108, 123518.]; Stanulis et al., 2014[Stanulis, A., Katelnikovas, A., Enseling, D., Dutczak, D., Šakirzanovas, S., Bael, M. V., Hardy, A., Kareiva, A. & Jüstel, T. (2014). Opt. Mater. 36, 1146-1152.]).

Pb2SnO4 has been used since the 14th century as a pigment and was frequently used in oil paintings before 1750. Nowadays the pigment is named lead-tin-yellow type I [see summary by Kühn (1993[Kühn, H. (1993). In Artists' Pigments. A Handbook of Their History and Characteristics, edited by A. Roy, vol. 2, pp. 83-112. Washington: National Gallery of Art.])]. Its structure at ambient conditions (Fig. 1[link]) was first proposed to have tetragonal space group symmetry P42/mbc (Byström & Westgren, 1943[Byström, A. & Westgren, A. (1943). Ark. Kemi. Mineral. Geol. 16, 7.]; Swanson et al., 1972[Swanson, H. E., McMurdie, H. F., Morris, M. C., Evans, E. H. & Paretzkin, B. (1972). Natl. Bur. Stand. (U. S.) Monogr. 25, 29.]). Later, the structure has been described in the orthorhombic space group Pbam (Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]).

[Figure 1]
Figure 1
Structure of Pb2SnO4 at ambient conditions from single-crystal structure solution. A 2 × 2 × 2 supercell is shown along the c axis. The SnO6 octahedra are shown in gray. A diagonal (3.74 Å) and a line between two opposite Pb2+ ions (4.11 Å) in one of the channels which run along the c axis.

In Pb2SnO4 the edge-sharing SnO6-octahedra form chains along the c-direction, interconnected within the (001) planes with Pb2+ ions. There are channels parallel to the c axis with a diameter of ≈ 3.74 Å (Fig. 1[link]). In Pb2SnO4 the Pb ions form the apex of a trigonal pyramid, i.e. there are only three short Pb—O distances. This points towards the presence of a stereochemically active lone electron pair. In contrast, in Ca2SnO4, where edge-sharing SnO6 octahedra also form chains, the Ca ions have seven nearest neighbors forming an irregular polyhedron.

At ambient conditions, the structure of Pb2SnO4 closely resembles that of the mineral minium (Pb2PbO4), which crystallizes at ambient conditions in the tetragonal space group P42/mbc. In Pb 22+Pb4+O4, the Pb4+ atoms are octahedrally coordinated. Pb2PbO4 has channels with a diameter of ∼3.8 Å (Gavarri & Weigel, 1975[Gavarri, J. R. & Weigel, D. (1975). J. Solid State Chem. 13, 252-257.]). Pb2PbO4 undergoes a temperature-induced phase transition below 170 K to space group Pbam (Gavarri et al., 1978[Gavarri, J. R., Weigel, D. & Hewat, A. W. (1978). J. Solid State Chem. 23, 327-339.]), so that Pb2SnO4 and Pb2PbO4 are isostructural at low temperatures, as the former shows no temperature-induced phase transition between 5 K and 300 K (Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]). For Pb2SnO4 the deviation from tetragonal symmetry remains small in this temperature range Δab = a − b = 0.0125 (6) Å at 300 K, Δab = 0.0139 (6) Å at 5 K].

Dinnebier et al. (2003[Dinnebier, R. E., Carlson, S., Hanfland, M. & Jansen, M. (2003). Am. Mineral. 88, 996-1002.]) found that Pb2PbO4 undergoes a pressure-induced phase transition from space group P42/mbc at ambient pressure to space group Pbam between 0.11 and 0.3 GPa and a second transition between 5.54 and 6.58 GPa to another orthorhombic phase, also having space group Pbam but with half the length of the c axis. Increasing pressure leads to an anisotropic compression of the a and b axes, with Δab ∼ 0 Å at ambient conditions to Δab ∼ 0.9 Å at 0.6 GPa and Δab ∼ 2.9 Å at 6.7 GPa.

The objective of this study was to characterize pressure-induced changes in structure–property relations of Pb2SnO4 at high pressures, as it was expected that by analogy with Pb2PbO4 the compound would undergo phase transitions and offer insight into the high-pressure behavior of stereochemically active lone electron pairs.

2. Experimental details

2.1. Sample synthesis

2.1.1. Solid-state synthesis

Temperatures between 923 K and 1173 K have been used for the synthesis of Pb2SnO4 powder by solid-state reaction (Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]; Hashemi et al., 1992[Hashemi, T., Brinkman, A. W. & Wilson, M. J. (1992). J. Mater. Sci. Lett. 11, 666-668.]; Clark et al., 1995[Clark, R. J. H., Cridland, L., Kariuki, B. M., Harris, K. D. M. & Withnall, R. (1995). J. Chem. Soc. Dalton Trans. pp. 2577.]; Chen et al., 2000[Chen, R., He, X. & Zhang, Q. (2000). Thermochim. Acta, 354, 121-123.]; Hradil et al., 2007[Hradil, D., Grygar, T., Hradilová, J., Bezdička, P., Grűnwaldová, V., Fogaš, I. & Miliani, C. (2007). J. Cult. Herit. 8, 377-386.]; Pelosi et al., 2010[Pelosi, C., Agresti, G., Santamaria, U. & Mattei, E. (2010). e-Preserv. Sci. 7, 108-115.]; Denisov et al., 2012[Denisov, V. M., Zhereb, V. P., Denisova, L. T., Irtyugo, L. A. & Kirik, S. D. (2012). Inorg. Mater. 48, 51-53.]; Agresti et al., 2016[Agresti, G., Baraldi, P., Pelosi, C. & Santamaria, U. (2016). Color. Res. Appl. 41, 226-231.]). For our experiments we chose a synthesis temperature of 1123 (1) K, in order to avoid the presence of PbSnO3 which decomposes above 1073 K and to prevent decomposition of Pb2SnO4 which is expected to occur above 1173 K (Xing et al., 2004[Xing, X., Chen, J., Wei, G., Deng, J. & Liu, G. (2004). J. Am. Ceram. Soc. 87, 1371-1373.]).

The starting materials were analytical grade and used as purchased: PbO (99.9+% purity, Sigma-Aldrich Chemie, Darmstadt) and SnO2 (99.9% purity, Alfa Aesar, Karlsruhe). Starting materials were mixed in stoichiometric proportions and ground in an agate mortar. The resulting mixture was pressed to 5 mm-sized pellets with an Across International Desktop pellet press at a pressure of 6 (1) Kbar. The pellets were placed in corundum crucibles with lids, transferred into a Nabertherm L08/14 muffle furnace, heated up to 1123 (1) K and annealed for 24 h. The samples were cooled down to ambient temperature by switching off the power supply. After the synthesis the pellets were ground again and the synthesis process was repeated two times.

2.1.2. Hydrothermal synthesis

Pb2SnO4 single crystals were hydrothermally grown in autoclaves according to a prescription by Wu et al. (1999[Wu, M., Li, X., Shen, G., He, D., Huang, A., Luo, Y., Feng, S. & Xu, R. (1999). Mater. Res. Bull. 34, 1135-1142.]), following the reaction

[\eqalignno{&2({\rm CH}_{3}{\rm COO})_{2}{\rm Pb}\,\, +\,\, {\rm Na}_{2}{\rm SnO}_{3}\,\, +\,\, 2{\rm NaOH}\rightarrow\cr & \,\,\,\,\,\,\,\,\,\,\,\,{\rm Pb}_{2}{\rm SnO}_{4}\downarrow \,\,+ \,\,4{\rm CH}_{3}{\rm COONa} + {\rm H}_{2}{\rm O}. &(2)}]

We used analytical grade Pb(CH3COO)2·3H2O (99.5% purity, Merck, Darmstadt), Na2SnO3·3H2O (98% purity, Alfa Aesar, Karlsruhe) and NaOH (99% purity, Merck, Darmstadt). The starting materials were dissolved separately in double distilled water to obtain solutions with 0.34 mol l−1 [Pb(CH3COO)2], 0.16 mol l−1 (Na2SnO3) and 2.0 mol l−1 (NaOH) concentration. First the Na2SnO3 and subsequently the NaOH solution were added dropwise to the Pb(CH3COO)2 solution while continuously stirring at ambient temperature. The resulting suspension was transferred into a 60 ml Teflon cup which was filled up to 60% of its volume and was then placed in stainless steel autoclaves. The autoclaves were heated up to 503 (1) K for 48 h, afterwards they were slowly cooled down to 298 (1) K within 72 h. The precipitate was recovered by vacuum filtration, washed with distilled water repeatedly and dried at 333 (1) K in an oven.

2.2. Sample characterization

2.2.1. X-ray powder diffraction at ambient pressure

The powder samples obtained from solid-state synthesis were characterized with a PANalytical X'Pert Pro powder diffractometer with Bragg–Brentano geometry and a PANalytical PIXcel3D detector. The diffractometer was equipped with a copper X-ray tube and a Johansson monochromator. The measurements were performed using Cu Kα1 radiation and 0.25° fixed divergence slits. The samples were measured in the range of 10° < 2θ < 90° with a scan speed of 0.036° min−1. The instrument parameters were refined using a measurement on a high purity (99.999%) Si-standard. Powder samples were mounted on an oriented Si single-crystal sample holder after grinding them in an agate mortar. Crystal structure refinements, based on the Rietveld method (Rietveld, 1969[Rietveld, H. M. (1969). J. Appl. Cryst. 2, 65-71.]), were carried out using the software package GSAS-II (Toby & Von Dreele, 2013[Toby, B. H. & Von Dreele, R. B. (2013). J. Appl. Cryst. 46, 544-549.]).

2.2.2. X-ray single-crystal diffraction at ambient pressure

Hydrothermally synthesized crystals were employed for the single-crystal diffraction experiments at ambient conditions. Measurements were carried out on an Oxford Instruments Xcalibur four-circle diffractometer with Kappa geometry and a Sapphire3 charge-coupled-device (CCD) detector. The diffractometer was equipped with a molybdenum X-ray tube and graphite single-crystal monochromator. The samples were measured with Mo Kα radiation. We measured a full sphere up to a resolution of 0.75 Å−1 and an exposure time of 120 s per frame. The crystals were mounted with Apiezon N grease on the tip of a glass capillary. Crystals of approximate dimensions 80 µm × 30 µm × 30 µm were centered in an X-ray beam of diameter 500 µm. The reflections were indexed and integrated using the CrysAlisPRO (v. 39.46) program (Agilent, 2014[Agilent (2014). CrysAlis PRO. Now Rigaku Oxford Diffraction, Yarnton, England.]). The structure solution was performed with SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]) and the refinement with the software package JANA2006 (Petricek et al., 2014[Petricek, V., Dusek, M. & Palatinus, L. (2014). Z. Kristallogr. 229, 345-352.]).

2.2.3. High-pressure experiments

All high-pressure experiments were carried out using Boehler–Almax-type diamond anvil cells (Boehler, 2006[Boehler, R. (2006). Rev. Sci. Instrum. 77, 115103.]). Depending on the target pressure of the experiments we used culet sizes between 250 µm and 350 µm and tungsten or rhenium as gasket material. Samples were placed in holes in the gasket having diameters between 100 µm and 180 µm. The gaskets were pre-indented to 40–50 µm and the holes were drilled by a custom-built laser setup. We used argon below 3 GPa for the powder diffraction and neon for all other experiments as pressure-transmitting media in pressure ranges where they provide a quasi-hydrostatic environment (Klotz et al., 2009[Klotz, S., Chervin, J.-C., Munsch, P. & Le Marchand, G. (2009). J. Phys. D Appl. Phys. 42, 1-7.]). Pressure was determined by measuring the ruby fluorescence shift. We assume an error of 2% for the pressure determination in the quasi-hydrostatic conditions present in our experiments (Dewaele et al., 2004[Dewaele, A., Loubeyre, P. & Mezouar, M. (2004). Phys. Rev. B, 70, 094112.], 2008[Dewaele, A., Torrent, M., Loubeyre, P. & Mezouar, M. (2008). Phys. Rev. B, 78, 104102.]).

2.2.4. High-pressure synchrotron X-ray diffraction

High-pressure diffraction data were collected at the synchrotron PETRA III (DESY) in Hamburg, Germany on the extreme conditions beamline P02.2 (Liermann et al., 2015[Liermann, H.-P., Konôpková, Z., Morgenroth, W., Glazyrin, K., Bednarčik, J., McBride, E. E., Petitgirard, S., Delitz, J. T., Wendt, M., Bican, Y., Ehnes, A., Schwark, I., Rothkirch, A., Tischer, M., Heuer, J., Schulte-Schrepping, H., Kracht, T. & Franz, H. (2015). J. Synchrotron Rad. 22, 908-924.]). We used a Perkin Elmer XRD1621 detector and wavelengths of 0.2887 Å and 0.2906 Å for data acquisition. The beam size was 2 µm (H) × 2  µm (V) (FWHM) obtained using a Kirkpatrick–Baez mirror for the powder diffraction experiments and 9 µm (H) × 3 µm (V) (FWHM) obtained using compound refractive lenses for the single-crystal diffraction measurements.

The powder samples were measured for 10 s while rotating them around a rotation axis perpendicular to the beam by ±10° to improve the counting statistics. For calibrating the detector parameters and the detector to sample distance we measured a CeO2 powder standard. We used the program DIOPTAS (Prescher & Prakapenka, 2015[Prescher, C. & Prakapenka, V. B. (2015). High. Press. Res. 35, 223-230.]) to integrate and calibrate the diffraction patterns.

For single-crystal diffraction the samples were rotated around a rotation axis perpendicular to the beam by ±33°. Frames were collected in 0.5° steps with 0.5 s acquisition time per frame. Pt-filters were used to reduce the primary intensity to prevent oversaturation of the detector. The diffractometer/detector geometry was calibrated by measuring an enstatite single crystal. Data treatment and crystal structure refinement were performed in a similar manner as for ambient-pressure single-crystal diffraction data.

The lattice parameters from the high-pressure powder diffraction data were obtained applying the Le Bail method (Le Bail et al., 1988[Le Bail, A., Duroy, H. & Fourquet, J. L. (1988). Mater. Res. Bull. 23, 447-452.]), using the software package GSAS-II (Toby & Von Dreele, 2013[Toby, B. H. & Von Dreele, R. B. (2013). J. Appl. Cryst. 46, 544-549.]). The bulk modulus from the high-pressure powder data was obtained by using the EoSFit7-GUI software package (Gonzalez-Platas et al., 2016[Gonzalez-Platas, J., Alvaro, M., Nestola, F. & Angel, R. (2016). J. Appl. Cryst. 49, 1377-1382.]), fitting a second-order Birch–Murnaghan equation of state (EoS) (Murnaghan, 1944[Murnaghan, F. (1944). Proc. Natl Acad. Sci. USA, 30, 244-247.]; Birch, 1947[Birch, F. (1947). Phys. Rev. 71, 809-824.]) to the unit-cell volume.

2.2.5. High-pressure electrical resistance measurements

High-pressure resistance measurements were carried out in diamond anvil cells (Fig. 2[link]) using a mixture of epoxy resin and Al2O3 as pressure-transmitting medium. We assume an error of the pressure determination due to non-hydrostatic conditions of 6% (Mao et al., 1986[Mao, H. K., Xu, J. & Bell, P. M. (1986). J. Geophys. Res. 91, 4673-4676.]). We performed both two-point and four-point measurements using a Keithley DMM7510 multimeter for the data collection as described in Zimmer et al. (2018[Zimmer, D., Ruiz-Fuertes, J., Morgenroth, W., Friedrich, A., Bayarjargal, L., Haussühl, E., Santamaría-Pérez, D., Frischkorn, S., Milman, V. & Winkler, B. (2018). Phys. Rev. B, 97, 134111.]).

[Figure 2]
Figure 2
Pb2SnO4 crystal connected to gold wires in a diamond anvil cell for resistance measurements using the four-point probes method at 4.3 (3) GPa.
2.2.6. Raman spectroscopy

Raman spectroscopy was carried out with a custom set-up described in detail in Bayarjargal et al. (2018[Bayarjargal, L., Fruhner, C.-J., Schrodt, N. & Winkler, B. (2018). Phys. Earth Planet. Inter. 281, 31-45.]). We used an OXXIUS S.A. LaserBoxx LMX532 laser (λ = 532.14 nm) and a Princeton Instruments ACTON SpectraPro 2300i spectrograph equipped with a Pixis256E CCD camera. All Raman spectra were background corrected with the software package Fityk (Wojdyr, 2010[Wojdyr, M. (2010). J. Appl. Cryst. 43, 1126-1128.]). High-pressure Raman spectroscopy was carried out in diamond anvil cells, similar to the high-pressure synchrotron X-ray diffraction experiments.

2.2.7. Scanning electron microscopy

We used a Phenom World ProX desktop SEM for the acquisition of electron backscatter images (BSE) on single crystals and powder samples. Furthermore, energy-dispersive X-ray spectroscopy (EDX) measurements for a semi-quantitative characterization of the composition were carried out on single crystals and powder samples. The samples were mounted without coating on aluminium stubs using sticky carbon tape. They were measured under low-vacuum conditions to reduce charging effects on the sample with an acceleration voltage of 10 KV for imaging and 15 KV for EDX measurements.

3. Computational details

First-principles calculations were carried out within the framework of density functional theory (DFT) (Hohenberg & Kohn, 1964[Hohenberg, P. & Kohn, W. (1964). Phys. Rev. 136, B864-B871.]), employing the Perdew–Burke–Ernzerhof (PBE) exchange-correlation function (Perdew et al., 1996[Perdew, J. P., Burke, K. & Ernzerhof, M. (1996). Phys. Rev. Lett. 77, 3865-3868.]) and the plane wave/pseudopotential approach implemented in the CASTEP (Clark et al., 2005[Clark, S. J., Segall, M. D., Pickard, C. J., Hasnip, P. J., Probert, M. I. J., Refson, K. & Payne, M. C. (2005). Z. Kristallogr. 220, 567-570.]) simulation package. `On the fly' norm-conserving or ultrasoft pseudopotentials generated using the descriptors in the CASTEP data base were employed in conjunction with plane waves up to a kinetic energy cutoff of 990 eV or 630 eV, for norm-conserving and ultrasoft pseudopotentials, respectively. The accuracy of the pseudopotentials is well established (Lejaeghere et al., 2016[Lejaeghere, K., Bihlmayer, G., Bjorkman, T., Blaha, P., Blugel, S., Blum, V., Caliste, D., Castelli, I. E., Clark, S. J., Dal Corso, A., de Gironcoli, S., Deutsch, T., Dewhurst, J. K., Di Marco, I., Draxl, C., Dułak, M., Eriksson, O., Flores-Livas, J. A., Garrity, K. F., Genovese, L., Giannozzi, P., Giantomassi, M., Goedecker, S., Gonze, X., Granas, O., Gross, E. K. U., Gulans, A., Gygi, F., Hamann, D. R., Hasnip, P. J., Holzwarth, N. A. W., Iusan, D., Jochym, D. B., Jollet, F., Jones, D., Kresse, G., Koepernik, K., Kucukbenli, E., Kvashnin, Y. O., Locht, I. L. M., Lubeck, S., Marsman, M., Marzari, N., Nitzsche, U., Nordström, L., Ozaki, T., Paulatto, L., Pickard, C. J., Poelmans, W., Probert, M. I. J., Refson, K., Richter, M., Rignanese, G.-M., Saha, S., Scheffler, M., Schlipf, M., Schwarz, K., Sharma, S., Tavazza, F., Thunström, P., Tkatchenko, A., Torrent, M., Vanderbilt, D., van Setten, M. J., Van Speybroeck, V., Wills, J. M., Yates, J. R., Zhang, G.-X. & Cottenier, S. (2016). Science, 351, aad3000.]). A Monkhorst–Pack (Monkhorst & Pack, 1976[Monkhorst, H. J. & Pack, J. D. (1976). Phys. Rev. B, 13, 5188-5192.]) grid was used for Brillouin-zone integrations with a distance of < 0.023 Å−1 between grid points. Convergence criteria included an energy change of < 5 × 10−6 eV atom−1 for scf-cycles, a maximal force of < 0.008 eVÅ−1, and a maximal component of the stress tensor < 0.02 GPa. Phonon frequencies were obtained from density functional perturbation theory (DFPT) calculations. Raman intensities were computed using DFPT with the `2n+1' theorem approach (Miwa, 2011[Miwa, K. (2011). Phys. Rev. B, 84, 094304.]) and a scissor operator of 5 eV. It should be stressed that all calculations are carried out in the athermal limit, i.e. the influence of temperature and zero-point motion is not taken into account.

4. Results

4.1. Synthesis

We synthesized Pb2SnO4 powder by solid-state reaction. The powder is slightly yellow at ambient conditions and does not show any distinct growth morphology [Fig. 3[link](a)]. From hydrothermal synthesis we obtained crystals with 50–150 µm lengths. Some crystals form aggregates, but many of them show a tetragonal crystal habit and idiomorphic crystal faces [Fig. 3[link]b]. Most of those crystals are colorless. The morphology of the single crystals is similar to that observed in an earlier study (Wu et al., 1999[Wu, M., Li, X., Shen, G., He, D., Huang, A., Luo, Y., Feng, S. & Xu, R. (1999). Mater. Res. Bull. 34, 1135-1142.]).

[Figure 3]
Figure 3
SEM image of slightly yellow Pb2SnO4 powder obtained by solid-state reaction (a) and of a colorless Pb2SnO4 crystal from hydrothermal synthesis (b).

The chemical composition obtained from the EDX measurements on the powders and single crystals do not substantially differ from the expected chemical composition (nominal versus EDX in at.%): PbO: 67/70 (4) and SnO2: 33/30 (3) for the powders from the solid-state reaction and PbO: 67/71 (4) and SnO2: 33/29 (3) for the single crystals from the hydrothermal synthesis. Furthermore, no impurities from other elements were observed in the EDX spectra.

4.2. Powder diffraction at ambient pressure

No secondary phase was detected by X-ray powder diffraction within the experimental detection limits of ∼3%. The phase purity of the powder was also confirmed by Rietveld refinement (Fig. 4[link]). The refinement of the powder data can be carried out in two space groups. A refinement in the tetragonal space group P42/mbc (wR = 12.1%) as well as in its orthorhombic subgroup Pbam (wR = 10.7%) with Z = 4 gave a satisfactory fit of the structural model to the diffraction data. Table 1[link] summarizes the diffraction data for Pb2SnO4 at ambient conditions. The refined crystallographic parameters for both space groups are also in good agreement with earlier studies (Swanson et al., 1972[Swanson, H. E., McMurdie, H. F., Morris, M. C., Evans, E. H. & Paretzkin, B. (1972). Natl. Bur. Stand. (U. S.) Monogr. 25, 29.]; Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]).

Table 1
Crystallographic data of Pb2SnO4 at ambient conditions obtained by single-crystal structure solution, Rietveld refinement on powder data and DFT-based calculations in comparison to data from Swanson et al. (1972[Swanson, H. E., McMurdie, H. F., Morris, M. C., Evans, E. H. & Paretzkin, B. (1972). Natl. Bur. Stand. (U. S.) Monogr. 25, 29.]) and Gavarri et al. (1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.])

  This study (tetragonal) This study (orthorhombic) Swanson et al. (1972[Swanson, H. E., McMurdie, H. F., Morris, M. C., Evans, E. H. & Paretzkin, B. (1972). Natl. Bur. Stand. (U. S.) Monogr. 25, 29.])† Gavarri et al. (1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.])‡§
  Single crystal Powder DFT Single crystal Powder DFT Powder Powder
Crystal system Tetragonal Orthorhombic Tetragonal Orthorhombic
Space group P42/mbc (No. 135) Pbam (No. 55) P42/mbc (No. 135) Pbam (No. 55)
a (Å) 8.7276 (2) 8.7387 (1) 8.9184 8.7288 (3) 8.7425 (2) 8.9298 8.7371 (4) 8.7215 (3)
b (Å) – – – 8.7263 (3) 8.7330 (2) 8.9103 – 8.7090 (3)
c (Å) 6.2970 (2) 6.3075 (1) 6.4713 6.2969 (2) 6.3068 (2) 6.4715 6.307 (1) 6.2919 (3)
Δab (Å) 0 0 0 0.0025 (4) 0.0095 (3) 0.0195 0 0.0125 (6)
V (Å3) 479.65 (2) 481.67 (2) 514.71 479.64 (3) 481.51 (4) 514.92 481.46 477.90 (4)
ρ (g cm−3) 8.268 8.234 7.705 8.269 8.236 7.702 8.237 8.323
Rint (%) 4.2 – – 4.1 – – – –
No. of unique reflections 349 109 – 679 216 – – ≈ 800
No. of refined parameters 22 24 – 40 33 – – 47
Refinement                
R (%) 2.1 8.8 – 2.5 7.7 – – 6.9
wR (%) 2.3 12.1 – 2.6 10.7 – – –
GOF 1.3 2.5 – 1.2 2.2 – – –
λ (Å) 0.71073 1.54056 – 0.71073 1.54056 – 1.54056 1.384 (2)
†ICDD No. 00-024-0589.
‡ICDD No. 01-075-1846.
§Neutron diffraction.
[Figure 4]
Figure 4
Rietveld refinements on a Pb2SnO4 powder sample from solid-state synthesis at ambient conditions in space group P42/mbc (a) and Pbam (b) using λ = 1.54056 Å. Reflection positions are indicated by tickmarks and the residuals between measurement and refinement are shown by the blue line.

The deviation from a tetragonal metric in the orthorhombic refinement [Δab = 0.0095 (3) Å] is very small and in good agreement with the value obtained by neutron powder diffraction data from Gavarri et al. (1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]) [Δab = 0.0125 (6) Å]. Furthermore, no peak splitting was observed in the diffraction data. The refinement in space group Pbam shows a slightly lower wR value compared to the refinement in space group P42/mbc. This is caused by the higher reflection to parameter ratio (6.5:1 for Pbam in contrast to 4.5:1 for P42/mbc).

4.3. Single-crystal diffraction at ambient pressure

The structure solution for Pb2SnO4 by Gavarri et al. (1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]) was performed on neutron powder data; here we carried out the first single crystal data collection and structure refinements. High-quality crystals from our hydrothermal synthesis are colorless at ambient conditions and suitable for single-crystal X-ray diffraction.

Similar to the results obtained from the powder diffraction data at ambient conditions, the refinement of the single crystal data gives very satisfactory results in two space groups. Both structure refinements in space group P42/mbc (wR = 2.3%) and in space group Pbam (wR = 2.6%) gave convincing structural models (Table 1[link]), which are in good agreement with the results of earlier studies (Swanson et al., 1972[Swanson, H. E., McMurdie, H. F., Morris, M. C., Evans, E. H. & Paretzkin, B. (1972). Natl. Bur. Stand. (U. S.) Monogr. 25, 29.]; Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]). Table 2[link] summarizes the atomic positions and anisotropic displacement parameters of Pb2SnO4 for the refinements in both space groups.

Table 2
Atom positions and anisotropic displacement parameters of Pb2SnO4 in space groups P42/mbc and Pbam from single-crystal structure refinement

Lattice parameters a, b, c in Å and atomic displacement parameters Uij in Å2.
  Atom Site a b c Ueq U11 U22 U33 U12 U13 U23
P42/mbc Pb 8h 0.16055 (5) 0.14197 (5) 0.5 0.0223 (1) 0.0225 (3) 0.0205 (3) 0.0239 (3) 0.0014 (2) 0 0
  Sn 4d 0.5 0 0.75 0.0181 (2) 0.0196 (3) 0.0196 (3) 0.0152 (5) 0.0015 (4) 0 0
  O1 8h 0.0973 (8) 0.3750 (8) 1.0 0.020 (2) 0.024 (4) 0.018 (4) 0.019 (4) −0.003 (3) 0 0
  O2 8g 0.3344 (6) 0.1656 (6) 0.75 0.025 (2) 0.027 (3) 0.027 (3) 0.022 (4) 0.003 (3) 0.004 (2) 0.004 (2)
Pbam Pb1 4g 0.16058 (5) 0.14191 (5) 0.5 0.0222 (2) 0.0226 (3) 0.0201 (3) 0.0239 (3) 0.0014 (2) 0 0
  Pb2 4h 0.35797 (5) 0.33984 (5) 1.0 0.0223 (2) 0.0226 (3) 0.0201 (3) 0.0239 (3) 0.0014 (2) 0 0
  Sn 4f 0.5 0 0.7502 (2) 0.0181 (3) 0.0196 (4) 0.0195 (5) 0.0152 (4) −0.0015 (3) 0 0
  O1 4h 0.0979 (8) 0.37653 (8) 1.0 0.021 (3) 0.023 (5) 0.019 (5) 0.021 (5) −0.002 (4) 0 0
  O2 8i 0.3344 (6) 0.16559 (6) 0.752 (1) 0.019 (3) 0.016 (4) 0.023 (5) 0.019 (5) −0.002 (4) 0 0
  O3 4g 0.1264 (6) 0.4381 (6) 0.5 0.025 (2) 0.022 (4) 0.032 (4) 0.022 (4) −0.003 (3) −0.003 (3) 0.004 (3)

The anisotropic displacement parameters do not differ substantially between the structure refinements in space group P42/mbc and Pbam. Lowering of the symmetry from P42/mbc to Pbam space group induces a splitting of the Wyckoff positions of the Pb1 and O1 atoms with 8h → 4g + 4h, but a detailed analysis showed no significant change in interatomic distances between the two refinements.

4.4. DFT calculations at ambient pressure

We cross-checked our experimental results with those of DFT-based calculations in both possible space groups for Pb2SnO4 (Tab. 1[link]). Our DFT-based calculations reproduce the experimental diffraction data satisfactorily with an overestimation of the unit-cell lengths by <3% due to the well established `underbinding' in DFT-GGA-PBE calculations. The DFT calculations carried out here provide structural and physical parameters in the athermal limit. As has been discussed in the introduction, structurally closely related Pb2PbO4 undergoes a tetragonal [\leftrightarrow] orthorhombic phase transition at 170 K, so it is actually problematic to neglect temperature in DFT studies of this system. The DFT-based calculations gave the same total energy within the numerical accuracy for the orthorhombic and the tetragonal structure.

Fig. 5[link] shows an isosurface of the electron density difference, i.e. shows charge accumulation with respect to the electron density obtained by overlapping non-interacting atomic densities.

[Figure 5]
Figure 5
Isosurface of the electron density difference at 0.03 e Å−1. Sn atoms, oxygen atoms and lead atoms are represented by violet, red and gray spheres, respectively. The yellow circle highlights a channel running parallel to [001], which hosts the 6s2 stereochemically active lone electron pairs of the Pb2+ ions, which appear as umbrella shaped surfaces.

Clearly discernible are the stereochemically-active 6s2 lone electron pairs of the Pb2+ ions, which appear in electron density difference isosurfaces as umbrella shaped objects (Friedrich et al., 2010[Friedrich, A., Juarez-Arellano, E. A., Haussühl, E., Boehler, R., Winkler, B., Wiehl, L., Morgenroth, W., Burianek, M. & Mühlberg, M. (2010). Acta Cryst. B66, 323-337.]). These electron pairs are located in the channels of the structure.

4.5. High-pressure single-crystal diffraction

We performed high-pressure single crystal X-ray diffraction measurements on Pb2SnO4 crystals up to 21.0 (4) GPa and solved and refined the crystal structure at numerous pressures (Table 3[link]). From the single crystal data we found that on pressure increase the unit cell of Pb2SnO4 is immediately strained and Δab increases from 0.0025 (4) Å at ambient pressure to its maximum of 2.799 (1) Å at 12.4 (3) GPa. After a pressure increase above ∼0.5 GPa the structure of Pb2SnO4 cannot be described in space group P42/mbc anymore and only a refinement in space group Pbam is satisfactory. At 7.8 (2) GPa (wR = 14.0%) and 10.0 (2) GPa (wR = 18.5%) the refinements of the structure in the space group Pbam yield increasingly worse reliability factors, but attempts to improve the description of the data by changing the structural model to another space group were unsuccessful.

Table 3
Selected crystallographic data of Pb2SnO4 obtained between ambient conditions and 21 GPa by synchrotron-based single-crystal structure refinements

The crystal was colorless at ambient conditions and had approximate dimensions 80 µm × 30 µm × 30 µm.
p (GPa) 0.0001† 2.0 (1) 5.5 (1) 7.8 (2) 10.0 (2) 12.4 (3) 15.2 (3) 21.0 (4)
Space group P42/mbc (No. 135) Pbam (No. 55) Pbam (No. 55) Pnam (No. 62)
a (Å) 8.7372 (2) 8.7397 (3) 9.1901 (7) 9.3799 (7) 9.3641 (6) 9.3169 (6) 9.2484 (8) 9.1830 (6) 9.0691 (6)
b (Å) – 8.7348 (3) 7.9508 (3) 7.2103 (3) 6.8646 (6) 6.6337 (6) 6.4498 (9) 6.4046 (6) 6.3282 (6)
c (Å) 6.3048 (2) 6.3047 (2) 6.2893 (7) 6.3250 (7) 6.3553 (2) 6.3808 (2) 6.4096 (2) 6.3727 (2) 6.3110 (2)
Δab (Å) 0 0.0049 (4) 1.2393 (8) 2.1696 (8) 2.4995 (9) 2.6832 (9) 2.799 (1) 2.7784 (9) 2.7409 (9)
V (Å3) 481.30 (2) 481.30 (3) 459.55 (6) 427.77 (6) 408.52 (5) 394.37 (5) 382.33 (6) 374.80 (4) 362.20 (4)
ρ (g cm−3) 8.240 8.240 8.630 9.271 9.708 10.056 10.373 10.582 10.950
Rint (%) 2.0 1.7 1.7 1.5 3.7 7.4 1.4 1.6 1.7
No. of unique reflections 770 1503 1011 898 1085 1004 814 814 813
No. of refined parameters 22 40 40 40 29‡ 26‡ 38 38 38
R (%) 2.0 2.2 2.3 2.1 8.7 13.9 1.9 2.0 2.4
wR (%) 2.7 2.9 2.9 2.9 14.0 18.5 2.3 2.7 2.9
GOF 1.8 1.7 1.4 1.6 5.1 6.0 1.2 1.4 1.4
†Opened diamond anvil cell after pressure release.
‡Anisotropic refinement of atomic displacement parameters was unsuccessful.

On further pressure increase we observed that Pb2SnO4 undergoes a phase transition from the orthorhombic space group Pbam (No. 55) to Pnam (No. 62) between 10 GPa and 12 GPa. At 12.4 (3) GPa (wR = 2.3%), the refinement in the high-pressure space group Pnam is convincing. We chose the unconventional Pnam setting of space group No. 62 in order to facilitate a comparison to the low-pressure structure. A symmetry check with the PLATON package (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]) was carried out to confirm the space group symmetry.

After pressure release we measured the same crystal in an opened diamond anvil cell at ambient conditions. The structure refinement shows that the pressure-induced straining of the unit cell and the pressure-induced phase transition is fully reversible on pressure release (Table 3[link]).

4.6. High-pressure powder diffraction

The high-pressure X-ray powder data complement the single-crystal data, as they have been measured for pressures up to 50 (1) GPa. We used the results from the single crystal refinement on Pb2SnO4 as starting model for the refinements of the powder diffraction data. Fig. 6[link] shows a Rietveld refinement of data collected at 12.0 (2) GPa, close to the pressure-induced structural phase transition. The refinement was carried out in space group Pnam. The anisotropic displacement parameters of the oxygen atoms were constrained to be identical and we applied restraints to ensure that the Sn—O bond distances are ∼2 Å. The high background is caused by diamonds and the pressure transmitting medium. The agreement between the experimental data and the structural model is convincing. The results obtained from the refinements of the powder data are in good agreement with the single crystal data collected up to 21 GPa.

[Figure 6]
Figure 6
Rietveld refinement of Pb2SnO4 at 12.0 (2) GPa in space group Pnam (wR = 2.7%) using λ = 0.2906 Å. Reflection positions are indicated by tickmarks and the residuals between measurement and refinement are shown by the blue line. Diamond and neon reflections were masked before data integration.

4.7. Deformation of the Pb2SnO4 unit cell

Fig. 7[link] shows the behavior of the Pb2SnO4 lattice parameters between ambient conditions and 30 GPa from single crystal and powder diffraction data in comparison to DFT-based calculations. Based on the single crystal and powder diffraction data we observed that the pressure dependence of the unit-cell parameters are very different up to pressures of ∼12 GPa. In this pressure regime, the a axis expands on pressure increase, the b axis shrinks, and the c axis remains essentially unchanged. This observation is supported by the DFT-based calculations.

[Figure 7]
Figure 7
Pressure-dependent behavior of the Pb2SnO4 lattice parameters, from single-crystal diffraction (blue), powder diffraction (red) and DFT calculations (black). The lattice parameter a is shown with black squares, b with filled circles and c with red diamonds.

4.8. Description of the high-pressure crystal structure

Fig. 8[link] shows the evolution of the crystal structure of Pb2SnO4 with increasing pressure. The pressure-induced elongation of the a axis and the compression in the b direction and the concomitant rearrangement of the Pb ions before the phase transition can clearly be observed.

[Figure 8]
Figure 8
Pb2SnO4 crystal structure viewed along the c axis at 2.0 (1) GPa (a), 7.8 (2) GPa (b) and 12.4 (3) GPa (c). Structure viewed along the a axis at 12.4 (3) GPa (d). 2 × 2 × 2 supercells are shown and the SnO6 octahedra are illustrated in gray.

The pressure-dependence of the Pb–Pb and Sn—O distances in Pb2SnO4 are shown in Fig. 9[link]. We observed that the SnO6 octahedra behave as quasi-rigid units in the crystal structure. The Sn—O bond lengths in the SnO6 octahedra remains approximately constant (∼2 Å) and are only slightly decreasing with increasing pressure. At ambient conditions the SnO6 octahedra have a volume of VSnO6 = 11.9 Å3 which is decreasing to VSnO6 = 11.1 Å3 at 21.0 (4) GPa. The distance between the opposite Pb2+ ions, forming the channels at ambient conditions (Fig. 1[link]), is decreasing by 1 Å with increasing pressure from ∼4.1 Å at ambient conditions to ∼3.1 Å at 12.4 (3) GPa. After the phase transition the Pb–Pb distance is almost independent of pressure.

[Figure 9]
Figure 9
Pb—Pb and Sn—O distances with increasing pressure from single-crystal diffraction (filled square) and DFT-based calculations (filled circle). Lines represent fits to the experimental data points.

The experimental finding of a phase transition was also supported by DFT-based calculations. The calculations imply, based on the enthalpy difference [\Delta H = H_{{Pbam}}-H_{{Pnam}}], that the phase transition from space group Pbam to Pnam occurs just below 10 GPa. The experimentally determined transition pressure and the results from the DFT-based calculations are therefore in good agreement.

The DFT calculations show a rather peculiar behavior of the stereochemically active lone electron pairs. While it is well established that such lone electron pairs may persist at high pressures [e.g. Friedrich et al. (2010[Friedrich, A., Juarez-Arellano, E. A., Haussühl, E., Boehler, R., Winkler, B., Wiehl, L., Morgenroth, W., Burianek, M. & Mühlberg, M. (2010). Acta Cryst. B66, 323-337.])] Fig. 10[link] shows that in Pb2SnO4 the lone electron pairs overlap on increasing pressure, i.e. there is bond formation along the Pb—Pb contacts both within the (001) planes and along the c direction.

[Figure 10]
Figure 10
Electron density difference maps obtained by DFT calculations of the pressure induced evolution of the stereochemically active lone electron pairs (highlighted by white circles) show that at high pressures there is a charge accumulation along the Pb—Pb contacts, i.e. Pb—Pb bonds have been formed by transferring 6s electrons of a Pb atom into empty 6p orbitals of a Pb atom <3 Å away. 2 × 2× 2 supercells are shown along the c axis.

The formation of Pb—Pb bonds has been discussed earlier [see e.g. reviews by Fischer & Power (2010[Fischer, R. C. & Power, P. P. (2010). Chem. Rev. 110, 3877-3923.]) and Nagase (2013[Nagase, S. (2012). Pure Appl. Chem. 85, 649-659.])] in diplumbenes, which have Pb—Pb bonds with bond distances of 2.9–4.1 Å. In the present case, the change in the electron density suggests the formation of dative bonds between the Pb2+ ions, i.e. bonds due to the interaction of the stereochemically active lone electron pairs of the donor atom with unoccupied orbitals of the acceptor atom. A Mulliken population analysis shows that the Pb 6p orbitals are filled slightly more on bond formation and the bond population between neighboring Pb2+ ions rises up to 0.28 e Å−3 at 80 GPa.

4.9. Bulk modulus of Pb2SnO4

We used the X-ray powder diffraction data to obtain the unit cell volume of Pb2SnO4 from ambient conditions up to 50 (1) GPa (Fig. 11[link]). These data sets were used to compute the values of the bulk modulus K for the low-pressure phase (Pbam) and the high-pressure phase (Pnam). We fitted a second-order Birch–Murnaghan equation of state to unit cell volume data up 10.4 (2) GPa for the low-pressure structure. The ambient-pressure volume V0 was not refined due to the limited data range for this structure and fixed to the volume obtained from ambient-pressure X-ray diffraction. For the high-pressure phase we fitted a second-order Birch–Murnaghan equation of state to the experimental data between 12.0 (2) GPa and 50 (1) GPa, refining the ambient-pressure volume V0 also. Table 4[link] lists the experimental values of K for both phases. The bulk moduli of the ambient-pressure phase [KPbam = 36 (2) GPa] and the high-pressure phase (KPnam = 117 (6) GPa) differ significantly.

Table 4
Bulk modulus of the low- and high-pressure structures of Pb2SnO4 from X-ray powder diffraction

  Kexp(GPa) V0 Å3)†
Pbam 36 (2) 479.64 (3)
Pnam 117 (6) 420 (3)
†Constrained to the value obtained from ambient-pressure X-ray diffraction.
[Figure 11]
Figure 11
Pressure dependence of the unit-cell volume of Pb2SnO4 from X-ray powder diffraction data. The second-order Birch–Murnaghan equation of state fitted to the experimental data for the low-pressure phase is shown in blue and for the high-pressure phase in red.

4.10. Resistance measurements

4.10.1. Calibrating the experimental set-up

We performed electrical resistance measurements as a function of pressure in diamond anvil cells. These measurements were calibrated by measuring pure silicon (99.999% purity, Alfa Aesar). At ambient pressure silicon crystallizes in space group [Fd{\bar 3}m] (No. 227) (Cohen & Chelikowsky, 1989[Cohen, M. L. & Chelikowsky, J. R. (1989). Electronic Structure and Optical Properties of Semiconductors. Berlin, Heidelberg: Springer-Verlag.]). Between 8 GPa and 12.5 GPa silicon undergoes a phase transition into the β-Sn structure with space group I41 (No. 141) (Garg et al., 2004[Garg, A. B., Vijayakumar, V. & Godwal, B. K. (2004). Rev. Sci. Instrum. 75, 2475-2478.]; Olijnyk et al., 1984[Olijnyk, H., Sikka, S. K. H. & Holzapfel, W. B. (1984). Phys. Lett. A, 103, 137-140.]; Weinstein & Piermarini, 1975[Weinstein, B. A. & Piermarini, G. J. (1975). Phys. Rev. B, 12, 1172-1186.]; Hu & Spain, 1986[Hu, J. Z. & Spain, I. L. (1984). Solid State Commun. 51, 263-266.]; Gupta & Ruoff, 1980[Gupta, M. C. & Ruoff, A. L. (1980). J. Appl. Phys. 51, 1072-1075.]; Hu et al., 1986[Hu, J. Z., Merkle, L. D., Menoni, C. S. & Spain, I. L. (1986). Phys. Rev. B, 34, 4679-4684.]; Yin & Cohen, 1982[Yin, M. T. & Cohen, M. L. (1982). Phys. Rev. B, 26, 5668-5687.]; McMahan & Moriarty, 1983[McMahan, A. K. & Moriarty, J. A. (1983). Phys. Rev. B, 27, 3235-3251.]; Chang & Cohen, 1985[Chang, K. J. & Cohen, M. L. (1985). Phys. Rev. B, 31, 7819-7826.]; Mizushima et al., 1994[Mizushima, K., Yip, S. & Kaxiras, E. (1994). Phys. Rev. B, 50, 14952-14959.]), accompanied by a decrease of the electrical resistance by ∼107 (Garg et al., 2004[Garg, A. B., Vijayakumar, V. & Godwal, B. K. (2004). Rev. Sci. Instrum. 75, 2475-2478.]; Minomura & Drickamer, 1962[Minomura, S. & Drickamer, H. G. (1962). J. Phys. Chem. Solids, 23, 451-456.]).

Our measurements from ambient conditions to 21 (1) GPa show a change of the resistance of > 106 (Fig. 12[link]). The resistance decreases by 104.5 within ∼2.5 GPa in the region of the phase transition from Si-I to Si-II and we determined a transition pressure of 8.4 (5) GPa. Garg et al. (2004[Garg, A. B., Vijayakumar, V. & Godwal, B. K. (2004). Rev. Sci. Instrum. 75, 2475-2478.]) measured a decrease of the resistance by 104.5 within ∼5 GPa and a transition pressure of 10.2 GPa using mylar embedded Al2O3 as pressure transmitting medium. In comparison to Garg et al. (2004[Garg, A. B., Vijayakumar, V. & Godwal, B. K. (2004). Rev. Sci. Instrum. 75, 2475-2478.]) the phase transition occurs in a much narrower pressure-range in our experiments, but at slightly lower pressures. The transition pressure obtained here is in good agreement with the data from Hu et al. (1986[Hu, J. Z., Merkle, L. D., Menoni, C. S. & Spain, I. L. (1986). Phys. Rev. B, 34, 4679-4684.]) who found that the phase transition occurs at lower pressures of ∼8.5 GPa in a non-hydrostatic environment in comparison to a transition pressure of 11.3 (2)–12.5 (2) GPa for quasi-hydrostatic conditions. Gupta & Ruoff (1980[Gupta, M. C. & Ruoff, A. L. (1980). J. Appl. Phys. 51, 1072-1075.]) found a sensitivity of the Si-I to Si-II phase transition to uniaxial stress and observed a change in the pressure-dependent resistance at 8 GPa by applying uniaxial stress along [111]. In summary, these calibration measurements show that our set-up allows us to accurately measure pressure-induced changes in the resistance but the sample environment is not hydrostatic.

[Figure 12]
Figure 12
Electrical resistance measurements on Si for calibrating and testing the experimental set-up as function of pressure using the four-point probe method up to 21 (1) GPa in comparison to data of Garg et al. (2004[Garg, A. B., Vijayakumar, V. & Godwal, B. K. (2004). Rev. Sci. Instrum. 75, 2475-2478.]).
4.10.2. Pressure-dependent resistance of Pb2SnO4

Pressure increase leads to a significant color change of Pb2SnO4 powder and single crystals. At ambient pressure, the crystals are colorless and the powder is lightly yellow. With increasing pressure the light yellow powder at ambient pressure and the single crystals became yellow (∼3 GPa), red (∼6 GPa) and brown (∼8 GPa). On further pressure increase the sample becomes opaque (Fig. 13[link]). All pressure-induced color changes are fully reversible on pressure release without hysteresis.

[Figure 13]
Figure 13
Pressure-dependent color change of Pb2SnO4 between 0 GPa and 17 (1) GPa in a diamond anvil cell.

The change in color is caused by a change in the absorption of visible light by the sample, indicative of a decrease in the band gap. Electrical resistance measurements were carried out between ambient pressure and 48 (3) GPa using two-point and four-point measurements (Fig. 2[link]). Below 14.2 (9) GPa the electrical resistance was above the detection limit of our experimental set-up (10 × 109 Ω).

The electrical resistance of Pb2SnO4 decreases by at least six orders of magnitude when the pressure is increased from ambient to ∼40 GPa (Fig. 14[link]). Due to the limitations of our experimental setup we were not able to determine the resistance of the sample across the structural phase transition. An extrapolation of the resistance to ambient pressure [using f(x) = A1·exp(−x/f1) + y0] suggests a resistivity > 1014 Ωm for Pb2SnO4, similar to insulators such as quartz or corundum. The results from the two-point probes and the four-point probes method are mutually consistent, as it is expected that two-point measurements will yield systematically higher values due to the additional contact resistance of the junction between the sample and the wires.

[Figure 14]
Figure 14
Electrical resistance measurements on Pb2SnO4 as function of pressure using the two-point probes and the four-point probes method (black). f(x) shows an exponential fit to the two-point probes measurement. Due to the limitation of the Keithley instrument employed, high resistances could not be observed. The DFT-calculated band gap is shown in red.

We calculated the band gap energy Eg between 0 and 50 GPa by DFT-based calculations and present it together with the electrical resistance measurement (Fig. 14[link]). The results of these calculations indicate that the band gap is closing between 40 GPa and 50 GPa. However, it is well established that DFT-GGA-PBE calculations underestimate the band gap energy by up to 50% and while the pressure-dependence of the experimentally determined electrical resistance and predicted band gap energy is similar, a quantitative evaluation would require more advanced model calculations. The closing of the band gap is also consistent with the observed pressure-induced change in color.

4.11. Raman spectroscopy

Raman spectroscopy was performed on powder samples and on a single crystal. Experimentally determined ambient-pressure Raman spectra of Pb2SnO4 were satisfactorily reproduced by a theoretical spectrum from DFT-based calculations independent of their synthesis route [Fig. 15[link](a)]. The theoretical Raman spectra for structures with space group symmetry of Pbam or P42/mbc are almost identical, therefore both reproduced the experimental data. The experimentally obtained Raman spectra are also in good agreement with the measurements from e.g. Clark et al. (1995[Clark, R. J. H., Cridland, L., Kariuki, B. M., Harris, K. D. M. & Withnall, R. (1995). J. Chem. Soc. Dalton Trans. pp. 2577.]) or Pelosi et al. (2010[Pelosi, C., Agresti, G., Santamaria, U. & Mattei, E. (2010). e-Preserv. Sci. 7, 108-115.]).

[Figure 15]
Figure 15
Ambient-pressure Raman spectra of Pb2SnO4 powder and a single crystal in comparison to results from DFT-based calculations (a) and Experimental Raman spectra of a Pb2SnO4 single crystal at 16.0 (3) GPa in comparison to results from DFT-based calculations at 15.2 GPa carried out in space group Pnam (b). The frequencies of the calculated Raman spectrum were rescaled by 8%.

According to a factor group analysis (DeAngelis et al., 1972[DeAngelis, B. A., Newnham, R. E. & White, W. B. (1972). Am. Mineral. 57, 255-268.]) for space group Pbam 42 modes (ΓRaman = 12 Ag + 12 B1g + 9 B2g + 9 B3g) and for space group P42/mbc 26 modes are Raman active (ΓRaman = 5 A1g + 7 B1g + 5 B2g + 9 Eg). We assigned irreducible representations to the observed peaks based on the DFT-based calculations in space group Pbam [Fig. 15[link](a)]. Table 5[link] shows the Raman shift of the experimental and calculated Raman modes in Pb2SnO4 together with the corresponding assignment to the irreducible representation from DFT-based calculations for Pbam.

Table 5
Peak positions (cm−1) of selected Raman modes of Pb2SnO4 from experimental data and DFT-based calculations at ambient conditions together with DFT-based mode assignments to irreducible representation

Experiment DFT [\Gamma _{{\rm {Raman}}}^{{Pbam}}]
56.2 46.0 Ag
78.3 72.4, 79.7, 79.7 Ag, B2g,3g
94.4 86.6 B1g
112.7 102.7, 102.7 B2g,3g
128.6 119.5 Ag
195.2 62.1, 62.9 B2g,3g
274.7 249.1 Ag
292.0 268.6 Ag
303.9 278.9 Ag
337.1 305.2 B1g
378.8 337.0, 337.0 B2g,3g
457.5 425.1 Ag
508.1 467.8, 467.8 B2g,3g
525.3 481.2, 481.2, 486.0, 490.7 B1g,2g,3g, Ag

Fig. 15[link](b) shows experimental Raman data at 16.0 (3) GPa in comparison to results from DFT-based calculations at 15.2 GPa. The agreement between the peak positions from the experimental data and DFT-based calculations for the high-pressure structure with Pnam space group symmetry is convincing and all experimentally observed Raman peaks can be assigned to their irreducible representations (ΓRaman = 12 Ag + 9 B1g + 12 B2g + 9 B3g). Table 6[link] shows the experimental and theoretical Raman data together with the corresponding assignment to the irreducible representation for the high-pressure space group Pnam.

Table 6
Peak positions (cm−1) of selected Raman modes of Pb2SnO4 from experimental [16.0 (3) GPa] data and DFT-based calculations (15.2 GPa) in the high-pressure space group Pnam together with DFT-based mode assignments to irreducible representation

Experiment DFT [\Gamma ^{Pbam}_{\rm Raman}]
93.1 81.2 Ag
113.8 103.1 B1g
130.8 119.3 Ag
146.9 138.1, 138.1 Ag, B2g
183.3 171.1 Ag
207.1 191.8 Ag
271.5 248.9, 254.0 Ag, B3g
358.6 329.3, 330.7, 334.0 Ag, B2g,3g
479.7 443.4 Ag
509.1 462.1, 462.5 Ag, B2g
646.7 592.2 Ag

5. Discussion and conclusion

The ambient pressure X-ray diffraction data of Pb2SnO4 can be successfully refined in two space groups (P42/mbc or Pbam) with very similar R values. Neither Raman spectroscopy nor DFT calculations can be used to unambiguously distinguish between the two space groups. While the structure of Pb2SnO4 is undoubtedly very nearly tetragonal, both earlier studies (Gavarri et al., 1981[Gavarri, J. R., Vigouroux, J. P., Calvarin, G. & Hewat, A. W. (1981). J. Solid State Chem. 36, 81-90.]) and the present experiments lead to the conclusion that there is a small deviation from P42/mbc and that hence the space group Pbam is the preferred choice for the structure of Pb2SnO4 at ambient conditions.

The high-pressure X-ray diffraction data and DFT-based calculations show a significant pressure-induced distortion from the quasi-tetragonal metric present at ambient conditions with increasing pressure. Pb2SnO4 with Pbam space group symmetry is stable up to 8–10 GPa, when a structural phase transition to a high-pressure structure with space group symmetry Pnam occurs. The experimentally observed structural phase transition is consistent with the results from the DFT-based calculations and Raman spectroscopic data. We observed no further phase transition of Pb2SnO4 up to 50 GPa.

The pressure-induced structural changes lead to a rearrangement of the Pb ions, while the chains formed by the edge-shared SnO6 octahedra remain essentially unchanged. The high-pressure phase is stabilized by the formation of Pb—Pb bonds. The presence of the Pb—Pb bonds at high pressures has been inferred from a Mulliken analysis of the electron density obtained from DFT calculations and from electron density difference maps. Our findings are consistent with earlier results on Pb—Pb bonding based on NMR measurements (Gabuda et al., 1999[Gabuda, S. P., Kozlova, S. G., Terskikh, V. V., Dybowski, C., Neue, G. & Perry, D. L. (1999). Solid State Nucl. Magn. Reson. 15, 103-107.]; Dybowski et al., 2001[Dybowski, C., Gabuda, S. P., Kozlova, S. G., Neue, G., Perry, D. L. & Terskikh, V. V. (2001). J. Solid State Chem. 157, 220-224.]), in which it was concluded that the Pb2+ 6p electron is involved.

The pressure-induced structural changes are accompanied by changes in the physical properties, such as a dramatic change in color and a large change in the resistivity. The experimentally obtained bulk moduli for the low- and high-pressure phase of Pb2SnO4 differ significantly [KPbam = 36 (2) GPa and KPnam = 117 (6) GPa]. A similar drastic change in the bulk moduli between the low and high-pressure phase has also been observed for the phase transition from phase II [Kphase II = 20.8 (4) GPa] to phase III [Kphase III = 98 (3)  GPa] in structurally closely related Pb2PbO4 (Dinnebier et al., 2003[Dinnebier, R. E., Carlson, S., Hanfland, M. & Jansen, M. (2003). Am. Mineral. 88, 996-1002.]). The pressure-induced changes in the structural and physical properties are fully reversible on pressure release.

In summary, Pb2SnO4 was shown to display an interesting high pressure behavior which is associated with a change of the properties of the stereochemically active lone electron pairs present at ambient conditions and the formation of Pb—Pb bonds. Studies to further characterize these bonds are currently underway.

Supporting information

CCDC references: 2030954; 2030955; 2030956; 2030957; 2030958; 2030959; 2030960; 2030961; 2030962

Crystal structure: contains datablocks global, Pb2SnO4-P42ombc-P0, Pb2SnO4-Pbam-P0, Pb2SnO4-Pbam-P1, Pb2SnO4-Pbam-P2, Pb2SnO4-Pbam-P3, Pb2SnO4-Pbam-P4, Pb2SnO4-Pnam-P5, Pb2SnO4-Pnam-P6, Pb2SnO4-Pnam-P7. DOI: https://doi.org/10.1107/S205252062001238X/xk5074sup1.cif

Structure factors: contains datablock Pb2SnO4-P42ombc-P0. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-P42ombc-P0sup2.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P1. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P1sup3.hkl

Structure factors: contains datablock Pb2SnO4-Pbam. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P0sup4.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P2. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P2sup5.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P3. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P3sup6.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P4. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P4sup7.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P5. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P5sup8.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P6. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P6sup9.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P7. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P7sup10.hkl


Computing details top

Tin(IV) Dilead Oxide (Pb2SnO4-P42ombc-P0) top
Crystal data top
O4Pb2SnDx = 8.268 Mg m−3
Mr = 597.11Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42/mbcCell parameters from 349 reflections
a = 8.7276 (2) Åθ = 4.7–29.1°
c = 6.2970 (2) ŵ = 75.09 mm−1
V = 479.65 (2) Å3T = 298 K
Z = 4Cuboid, colourless
F(000) = 9840.08 × 0.04 × 0.03 mm
Data collection top
Xcalibur, Sapphire3
diffractometer		349 independent reflections
Radiation source: X-ray tube304 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.042
Detector resolution: 15.9682 pixels mm-1θmax = 29.1°, θmin = 4.7°
ω scansh = −11→11
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		k = −11→11
Tmin = 0.027, Tmax = 0.05l = −8→8
6359 measured reflections
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.021Secondary atom site location: difference Fourier map
wR(F2) = 0.025Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.26(Δ/σ)max = 0.003
349 reflectionsΔρmax = 0.38 e Å−3
22 parametersΔρmin = −0.40 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 42 (11)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.85801 (5)0.16055 (5)00.02231 (16)
Sn10.500.250.0181 (2)
O10.6250 (8)0.0973 (8)0.50.020 (2)
O20.3344 (6)0.1656 (6)0.250.0251 (19)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.0225 (3)0.0205 (3)0.0239 (3)0.00144 (15)00
Sn10.0196 (3)0.0196 (3)0.0152 (5)0.0015 (4)00
O10.024 (4)0.018 (4)0.019 (4)−0.003 (3)00
O20.027 (3)0.027 (3)0.022 (4)0.003 (3)0.004 (2)0.004 (2)
Geometric parameters (Å, º) top
Pb1—O1i2.296 (7)Sn1—O1vi2.095 (5)
Pb1—O2ii2.196 (4)Sn1—O1i2.095 (5)
Pb1—O2iii2.196 (4)Sn1—O1vii2.095 (5)
Sn1—Sn1iv3.1485 (2)Sn1—O22.044 (5)
Sn1—Sn1v3.1485 (2)Sn1—O2vi2.044 (5)
Sn1—O12.095 (5)
O1i—Pb1—O2ii90.02 (18)O1—Sn1—O294.7 (2)
O1i—Pb1—O2iii90.02 (18)O1—Sn1—O2vi85.3 (2)
O2ii—Pb1—O2iii91.59 (14)O1vi—Sn1—O1i170.6 (3)
Sn1iv—Sn1—Sn1v180.0 (5)O1vi—Sn1—O1vii98.2 (2)
Sn1iv—Sn1—O1138.71 (14)O1vi—Sn1—O285.3 (2)
Sn1iv—Sn1—O1vi138.71 (14)O1vi—Sn1—O2vi94.7 (2)
Sn1iv—Sn1—O1i41.29 (14)O1i—Sn1—O1vii82.6 (2)
Sn1iv—Sn1—O1vii41.29 (14)O1i—Sn1—O285.3 (2)
Sn1iv—Sn1—O290O1i—Sn1—O2vi94.7 (2)
Sn1iv—Sn1—O2vi90O1vii—Sn1—O294.7 (2)
Sn1v—Sn1—O141.29 (14)O1vii—Sn1—O2vi85.3 (2)
Sn1v—Sn1—O1vi41.29 (14)O2—Sn1—O2vi180.0 (5)
Sn1v—Sn1—O1i138.71 (14)Pb1i—O1—Sn1118.2 (2)
Sn1v—Sn1—O1vii138.71 (14)Pb1i—O1—Sn1v118.2 (2)
Sn1v—Sn1—O290Sn1—O1—Sn1v97.4 (3)
Sn1v—Sn1—O2vi90Pb1viii—O2—Pb1ix130.1 (2)
O1—Sn1—O1vi82.6 (2)Pb1viii—O2—Sn1114.97 (18)
O1—Sn1—O1i98.2 (2)Pb1ix—O2—Sn1114.97 (18)
O1—Sn1—O1vii170.6 (3)
Symmetry codes: (i) y+1/2, x−1/2, −z+1/2; (ii) −y+1, x, z−1/2; (iii) −y+1, x, −z+1/2; (iv) −x+1, −y, −z; (v) −x+1, −y, −z+1; (vi) −x+1, −y, z; (vii) −y+1/2, −x+1/2, −z+1/2; (viii) y, −x+1, z+1/2; (ix) x−1/2, −y+1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P0) top
Crystal data top
O4Pb2SnDx = 8.269 Mg m−3
Mr = 597.11Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbamCell parameters from 679 reflections
a = 8.7288 (3) Åθ = 4.6–29.1°
b = 8.7263 (3) ŵ = 75.09 mm−1
c = 6.2969 (2) ÅT = 298 K
V = 479.64 (3) Å3Cuboid, colourless
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Xcalibur, Sapphire3
diffractometer		679 independent reflections
Radiation source: X-ray tube540 reflections with I > 3σ(I)
Graphite monochromatorRint = 0.041
Detector resolution: 15.9682 pixels mm-1θmax = 29.1°, θmin = 4.6°
ω scansh = −11→11
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		k = −11→11
Tmin = 0.027, Tmax = 0.05l = −8→8
6760 measured reflections
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.025Secondary atom site location: difference Fourier map
wR(F2) = 0.028Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.20(Δ/σ)max = 0.006
679 reflectionsΔρmax = 0.49 e Å−3
40 parametersΔρmin = −0.42 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 39 (9)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.35799 (6)0.16055 (6)00.02222 (17)
Pb20.16058 (5)0.35808 (6)−0.50.02232 (18)
Sn10.50.5−0.24980 (16)0.0181 (3)
O10.1264 (10)0.0962 (11)−0.50.021 (3)
O20.0979 (10)0.1235 (10)00.019 (3)
O30.3344 (7)0.3344 (8)−0.2479 (12)0.025 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.0226 (3)0.0201 (3)0.0239 (3)0.00143 (19)00
Pb20.0207 (3)0.0225 (3)0.0238 (3)0.00141 (19)00
Sn10.0196 (4)0.0195 (5)0.0152 (4)−0.0015 (3)00
O10.023 (5)0.019 (5)0.021 (5)−0.002 (4)00
O20.016 (4)0.023 (5)0.019 (5)−0.002 (4)00
O30.022 (4)0.032 (4)0.022 (4)−0.003 (3)−0.003 (3)0.004 (3)
Geometric parameters (Å, º) top
Pb1—O22.293 (9)Sn1—Sn1iv3.1459 (14)
Pb1—O32.186 (7)Sn1—O1v2.099 (6)
Pb1—O3i2.186 (7)Sn1—O1vi2.099 (6)
Pb2—O12.305 (10)Sn1—O2vii2.089 (6)
Pb2—O32.206 (7)Sn1—O2viii2.089 (6)
Pb2—O3ii2.206 (7)Sn1—O32.044 (7)
Sn1—Sn1iii3.1510 (14)Sn1—O3ix2.044 (7)
O2—Pb1—O390.3 (2)O1v—Sn1—O385.1 (3)
O2—Pb1—O3i90.3 (2)O1v—Sn1—O3ix95.4 (3)
O3—Pb1—O3i91.1 (3)O1vi—Sn1—O2vii170.6 (3)
O1—Pb2—O389.8 (2)O1vi—Sn1—O2viii98.3 (3)
O1—Pb2—O3ii89.8 (2)O1vi—Sn1—O395.4 (3)
O3—Pb2—O3ii92.1 (3)O1vi—Sn1—O3ix85.1 (3)
Sn1iii—Sn1—Sn1iv180.0 (5)O2vii—Sn1—O2viii82.3 (3)
Sn1iii—Sn1—O1v41.35 (19)O2vii—Sn1—O394.1 (3)
Sn1iii—Sn1—O1vi41.35 (19)O2vii—Sn1—O3ix85.4 (3)
Sn1iii—Sn1—O2vii138.83 (18)O2viii—Sn1—O385.4 (3)
Sn1iii—Sn1—O2viii138.83 (18)O2viii—Sn1—O3ix94.1 (3)
Sn1iii—Sn1—O390.3 (2)O3—Sn1—O3ix179.3 (3)
Sn1iii—Sn1—O3ix90.3 (2)Pb2—O1—Sn1x117.7 (3)
Sn1iv—Sn1—O1v138.65 (19)Pb2—O1—Sn1xi117.7 (3)
Sn1iv—Sn1—O1vi138.65 (19)Sn1x—O1—Sn1xi97.3 (4)
Sn1iv—Sn1—O2vii41.17 (18)Pb1—O2—Sn1xii118.5 (3)
Sn1iv—Sn1—O2viii41.17 (18)Pb1—O2—Sn1xi118.5 (3)
Sn1iv—Sn1—O389.7 (2)Sn1xii—O2—Sn1xi97.7 (4)
Sn1iv—Sn1—O3ix89.7 (2)Pb1—O3—Pb2130.1 (3)
O1v—Sn1—O1vi82.7 (3)Pb1—O3—Sn1115.3 (3)
O1v—Sn1—O2vii98.3 (3)Pb2—O3—Sn1114.6 (3)
O1v—Sn1—O2viii170.6 (3)
Symmetry codes: (i) x, y, −z; (ii) x, y, −z−1; (iii) −x+1, −y+1, −z−1; (iv) −x+1, −y+1, −z; (v) −x+1/2, y+1/2, −z−1; (vi) x+1/2, −y+1/2, −z−1; (vii) −x+1/2, y+1/2, −z; (viii) x+1/2, −y+1/2, −z; (ix) −x+1, −y+1, z; (x) −x+1/2, y−1/2, −z−1; (xi) x−1/2, −y+1/2, z; (xii) −x+1/2, y−1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P1) top
Crystal data top
O4Pb2SnDx = 8.63 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PbamCell parameters from 1011 reflections
a = 9.1901 (7) Åθ = 1.9–17.9°
b = 7.9508 (3) ŵ = 9.87 mm−1
c = 6.2893 (7) ÅT = 293 K
V = 459.55 (6) Å3Cuboid, colourless
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		1011 independent reflections
Radiation source: synchrotron848 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.017
ω scansθmax = 17.9°, θmin = 1.9°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −16→15
Tmin = 0.012, Tmax = 0.02k = −13→12
2491 measured reflectionsl = −12→13
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.023Secondary atom site location: difference Fourier map
wR(F2) = 0.031Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.41(Δ/σ)max = 0.009
1011 reflectionsΔρmax = 1.46 e Å−3
40 parametersΔρmin = −0.92 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 610 (50)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.33997 (3)0.13860 (4)00.01371 (9)
Pb20.17244 (3)0.38926 (4)−0.50.01373 (9)
Sn10.50.5−0.24865 (6)0.01054 (15)
O10.3868 (7)0.6101 (8)−0.50.0122 (18)
O20.6679 (5)0.6684 (6)−0.2496 (6)0.0163 (13)
O30.4113 (6)0.6399 (8)00.0122 (18)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.01396 (16)0.0134 (2)0.01379 (10)0.00039 (7)00
Pb20.01124 (16)0.0142 (2)0.01579 (10)0.00089 (6)00
Sn10.0113 (3)0.0125 (3)0.00781 (13)−0.00090 (11)00
O10.023 (3)0.005 (4)0.0087 (14)0.0038 (16)00
O20.021 (2)0.014 (3)0.0141 (12)−0.0052 (12)0.0061 (14)−0.0045 (16)
O30.021 (4)0.008 (4)0.0079 (14)0.0019 (15)00
Geometric parameters (Å, º) top
Pb1—O2i2.196 (4)Sn1—Sn1ii3.1276 (9)
Pb1—O2ii2.196 (4)Sn1—O12.085 (4)
Pb1—O3iii2.309 (6)Sn1—O1i2.085 (4)
Pb2—Pb2iv3.6258 (6)Sn1—O22.043 (5)
Pb2—O1v2.285 (6)Sn1—O2i2.043 (5)
Pb2—O2i2.201 (4)Sn1—O32.085 (4)
Pb2—O2vi2.201 (4)Sn1—O3i2.085 (4)
Sn1—Sn1vi3.1617 (9)
O2i—Pb1—O2ii91.24 (16)O1—Sn1—O295.7 (2)
O2i—Pb1—O3iii87.93 (16)O1—Sn1—O2i84.0 (2)
O2ii—Pb1—O3iii87.93 (16)O1—Sn1—O398.60 (18)
Pb2iv—Pb2—O1v105.27 (16)O1—Sn1—O3i171.0 (2)
Pb2iv—Pb2—O2i133.16 (11)O1i—Sn1—O284.0 (2)
Pb2iv—Pb2—O2vi133.16 (11)O1i—Sn1—O2i95.7 (2)
O1v—Pb2—O2i87.51 (17)O1i—Sn1—O3171.0 (2)
O1v—Pb2—O2vi87.51 (17)O1i—Sn1—O3i98.60 (18)
O2i—Pb2—O2vi91.37 (16)O2—Sn1—O2i179.66 (15)
Sn1vi—Sn1—Sn1ii180.0 (5)O2—Sn1—O387.0 (2)
Sn1vi—Sn1—O140.70 (13)O2—Sn1—O3i93.2 (2)
Sn1vi—Sn1—O1i40.70 (13)O2i—Sn1—O393.2 (2)
Sn1vi—Sn1—O289.83 (11)O2i—Sn1—O3i87.0 (2)
Sn1vi—Sn1—O2i89.83 (11)O3—Sn1—O3i82.82 (18)
Sn1vi—Sn1—O3138.59 (13)Pb2vii—O1—Sn1121.78 (19)
Sn1vi—Sn1—O3i138.59 (13)Pb2vii—O1—Sn1vi121.78 (19)
Sn1ii—Sn1—O1139.30 (13)Sn1—O1—Sn1vi98.6 (3)
Sn1ii—Sn1—O1i139.30 (13)Pb1i—O2—Pb2i132.8 (2)
Sn1ii—Sn1—O290.17 (11)Pb1i—O2—Sn1115.52 (19)
Sn1ii—Sn1—O2i90.17 (11)Pb2i—O2—Sn1111.7 (2)
Sn1ii—Sn1—O341.41 (13)Pb1viii—O3—Sn1112.87 (19)
Sn1ii—Sn1—O3i41.41 (13)Pb1viii—O3—Sn1ii112.87 (19)
O1—Sn1—O1i81.41 (19)Sn1—O3—Sn1ii97.2 (3)
Symmetry codes: (i) −x+1, −y+1, z; (ii) −x+1, −y+1, −z; (iii) −x+1/2, y−1/2, −z; (iv) −x, −y+1, z; (v) −x+1/2, y−1/2, −z−1; (vi) −x+1, −y+1, −z−1; (vii) −x+1/2, y+1/2, −z−1; (viii) −x+1/2, y+1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P2) top
Crystal data top
O4Pb2SnDx = 9.271 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PbamCell parameters from 898 reflections
a = 9.3799 (7) Åθ = 2.0–17.8°
b = 7.2103 (3) ŵ = 10.60 mm−1
c = 6.3250 (7) ÅT = 293 K
V = 427.77 (6) Å3Cuboid, orange
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		898 independent reflections
Radiation source: synchrotron824 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.015
ω scansθmax = 17.8°, θmin = 2.0°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −16→17
Tmin = 0.009, Tmax = 0.017k = −11→10
2276 measured reflectionsl = −13→12
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.021Secondary atom site location: difference Fourier map
wR(F2) = 0.029Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.60(Δ/σ)max = 0.008
898 reflectionsΔρmax = 1.14 e Å−3
40 parametersΔρmin = −1.44 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 890 (50)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.32870 (3)0.11814 (5)00.01235 (9)
Pb20.17591 (3)0.43375 (5)−0.50.01221 (9)
Sn10.50.5−0.24846 (5)0.00974 (13)
O10.4030 (6)0.6348 (9)−0.50.0117 (16)
O20.6766 (4)0.6632 (7)−0.2490 (6)0.0156 (13)
O30.4181 (5)0.6571 (8)00.0103 (16)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.01252 (14)0.0126 (2)0.01198 (9)0.00008 (6)00
Pb20.01056 (14)0.0129 (2)0.01322 (9)0.00035 (6)00
Sn10.0102 (2)0.0113 (3)0.00773 (12)−0.00080 (10)00
O10.012 (3)0.014 (4)0.0091 (12)0.0032 (13)00
O20.019 (2)0.015 (3)0.0127 (10)−0.0040 (11)0.0029 (12)−0.0043 (15)
O30.013 (3)0.010 (4)0.0081 (11)−0.0005 (13)00
Geometric parameters (Å, º) top
Pb1—Pb1i3.6372 (6)Pb2—O2iv2.218 (4)
Pb1—Pb2ii3.4309 (7)Pb2—O2vii2.218 (4)
Pb1—Pb2iii3.4309 (7)Sn1—Sn1vii3.1822 (8)
Pb1—O2iv2.230 (4)Sn1—Sn1v3.1428 (8)
Pb1—O2v2.230 (4)Sn1—O12.077 (4)
Pb1—O3iii2.334 (5)Sn1—O1iv2.077 (4)
Pb2—Pb2vi3.4353 (6)Sn1—O22.032 (4)
Pb2—Sn13.4644 (5)Sn1—O2iv2.032 (4)
Pb2—Sn1vii3.4644 (5)Sn1—O32.083 (4)
Pb2—O1ii2.276 (6)Sn1—O3iv2.083 (4)
Pb1i—Pb1—Pb2ii80.188 (7)Pb2—Sn1—O2iv37.23 (11)
Pb1i—Pb1—Pb2iii80.188 (7)Pb2—Sn1—O395.66 (13)
Pb1i—Pb1—O2iv110.58 (10)Pb2—Sn1—O3iv126.46 (15)
Pb1i—Pb1—O2v110.58 (10)Pb2iv—Sn1—Sn1vii62.660 (6)
Pb1i—Pb1—O3iii158.98 (14)Pb2iv—Sn1—Sn1v117.340 (6)
Pb2ii—Pb1—Pb2iii134.374 (13)Pb2iv—Sn1—O188.18 (13)
Pb2ii—Pb1—O2iv67.87 (11)Pb2iv—Sn1—O1iv47.78 (15)
Pb2ii—Pb1—O2v157.64 (11)Pb2iv—Sn1—O237.23 (11)
Pb2ii—Pb1—O3iii91.96 (6)Pb2iv—Sn1—O2iv142.66 (11)
Pb2iii—Pb1—O2iv157.64 (11)Pb2iv—Sn1—O3126.46 (15)
Pb2iii—Pb1—O2v67.87 (11)Pb2iv—Sn1—O3iv95.66 (13)
Pb2iii—Pb1—O3iii91.96 (6)Sn1vii—Sn1—Sn1v180.0 (5)
O2iv—Pb1—O2v89.82 (15)Sn1vii—Sn1—O139.98 (12)
O2iv—Pb1—O3iii83.82 (15)Sn1vii—Sn1—O1iv39.98 (12)
O2v—Pb1—O3iii83.82 (15)Sn1vii—Sn1—O289.92 (10)
Pb1viii—Pb2—Pb1ix134.374 (13)Sn1vii—Sn1—O2iv89.92 (10)
Pb1viii—Pb2—Pb2vi83.117 (7)Sn1vii—Sn1—O3138.97 (12)
Pb1viii—Pb2—Sn1112.389 (9)Sn1vii—Sn1—O3iv138.97 (12)
Pb1viii—Pb2—Sn1vii62.239 (7)Sn1v—Sn1—O1140.02 (12)
Pb1viii—Pb2—O1ii111.25 (2)Sn1v—Sn1—O1iv140.02 (12)
Pb1viii—Pb2—O2iv142.15 (10)Sn1v—Sn1—O290.08 (10)
Pb1viii—Pb2—O2vii57.97 (11)Sn1v—Sn1—O2iv90.08 (10)
Pb1ix—Pb2—Pb2vi83.117 (7)Sn1v—Sn1—O341.03 (12)
Pb1ix—Pb2—Sn162.239 (7)Sn1v—Sn1—O3iv41.03 (12)
Pb1ix—Pb2—Sn1vii112.389 (9)O1—Sn1—O1iv79.97 (17)
Pb1ix—Pb2—O1ii111.25 (2)O1—Sn1—O294.88 (19)
Pb1ix—Pb2—O2iv57.97 (11)O1—Sn1—O2iv85.00 (19)
Pb1ix—Pb2—O2vii142.15 (10)O1—Sn1—O399.29 (17)
Pb2vi—Pb2—Sn1143.563 (9)O1—Sn1—O3iv174.1 (2)
Pb2vi—Pb2—Sn1vii143.563 (9)O1iv—Sn1—O285.00 (19)
Pb2vi—Pb2—O1ii87.20 (13)O1iv—Sn1—O2iv94.88 (19)
Pb2vi—Pb2—O2iv133.32 (10)O1iv—Sn1—O3174.1 (2)
Pb2vi—Pb2—O2vii133.32 (10)O1iv—Sn1—O3iv99.29 (17)
Sn1—Pb2—Sn1vii54.679 (10)O2—Sn1—O2iv179.85 (14)
Sn1—Pb2—O1ii114.55 (11)O2—Sn1—O389.24 (18)
Sn1—Pb2—O2iv33.65 (11)O2—Sn1—O3iv90.88 (18)
Sn1—Pb2—O2vii79.94 (10)O2iv—Sn1—O390.88 (18)
Sn1vii—Pb2—O1ii114.55 (11)O2iv—Sn1—O3iv89.24 (18)
Sn1vii—Pb2—O2iv79.94 (10)O3—Sn1—O3iv82.06 (16)
Sn1vii—Pb2—O2vii33.65 (11)Pb2viii—O1—Sn1125.92 (16)
O1ii—Pb2—O2iv84.55 (15)Pb2viii—O1—Sn1vii125.92 (16)
O1ii—Pb2—O2vii84.55 (15)Sn1—O1—Sn1vii100.0 (2)
O2iv—Pb2—O2vii91.45 (14)Pb1iv—O2—Pb2iv137.9 (2)
Pb2—Sn1—Pb2iv125.321 (11)Pb1iv—O2—Sn1112.95 (17)
Pb2—Sn1—Sn1vii62.660 (6)Pb2iv—O2—Sn1109.12 (19)
Pb2—Sn1—Sn1v117.340 (6)Pb1ix—O3—Sn1107.45 (18)
Pb2—Sn1—O147.78 (15)Pb1ix—O3—Sn1v107.45 (18)
Pb2—Sn1—O1iv88.18 (13)Sn1—O3—Sn1v97.9 (2)
Pb2—Sn1—O2142.66 (11)
Symmetry codes: (i) −x+1, −y, z; (ii) −x+1/2, y−1/2, −z−1; (iii) −x+1/2, y−1/2, −z; (iv) −x+1, −y+1, z; (v) −x+1, −y+1, −z; (vi) −x, −y+1, z; (vii) −x+1, −y+1, −z−1; (viii) −x+1/2, y+1/2, −z−1; (ix) −x+1/2, y+1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P3) top
Crystal data top
O4Pb2SnDx = 9.708 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PbamCell parameters from 1085 reflections
a = 9.3641 (6) Åθ = 2.0–18.0°
b = 6.8646 (6) ŵ = 11.1 mm−1
c = 6.3553 (2) ÅT = 293 K
V = 408.52 (5) Å3Cuboid, red
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		1085 independent reflections
Radiation source: synchrotron966 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.037
ω scansθmax = 18.0°, θmin = 2.0°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −17→18
Tmin = 0.008, Tmax = 0.016k = −9→12
2571 measured reflectionsl = −12→13
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.087Secondary atom site location: difference Fourier map
wR(F2) = 0.143Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 5.06(Δ/σ)max = 0.014
1085 reflectionsΔρmax = 3.22 e Å−3
29 parametersΔρmin = −2.85 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 580 (50)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.32668 (15)0.1042 (3)00.0128 (4)
Pb20.17615 (14)0.4628 (3)−0.50.0120 (4)
Sn10.50.5−0.2439 (3)0.0100 (7)
O10.403 (2)0.635 (4)−0.50.004 (3)*
O20.682 (3)0.660 (5)−0.255 (3)0.021 (4)*
O30.417 (3)0.660 (6)00.015 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.0122 (6)0.0142 (10)0.0121 (4)0.0002 (3)00
Pb20.0114 (6)0.0110 (9)0.0135 (5)0.0002 (3)00
Sn10.0101 (10)0.0141 (16)0.0057 (6)−0.0014 (6)00
Geometric parameters (Å, º) top
Pb1—Pb1i3.547 (2)Pb2—O2iv2.21 (3)
Pb1—Pb2ii3.3227 (9)Pb2—O2vii2.21 (3)
Pb1—Pb2iii3.3227 (9)Sn1—Sn1vii3.255 (3)
Pb1—O2iv2.29 (3)Sn1—Sn1v3.100 (3)
Pb1—O2v2.29 (3)Sn1—O12.082 (15)
Pb1—O3iii2.31 (3)Sn1—O1iv2.082 (15)
Pb2—Pb2vi3.3384 (19)Sn1—O22.03 (3)
Pb2—Sn13.4513 (15)Sn1—O2iv2.03 (3)
Pb2—Sn1vii3.4513 (15)Sn1—O32.05 (2)
Pb2—O12.43 (2)Sn1—O3iv2.05 (2)
Pb2—O1ii2.37 (3)
Pb1i—Pb1—Pb2ii83.66 (4)Pb2—Sn1—O144.0 (6)
Pb1i—Pb1—Pb2iii83.66 (4)Pb2—Sn1—O1iv89.0 (5)
Pb1i—Pb1—O2iv108.5 (7)Pb2—Sn1—O2139.6 (7)
Pb1i—Pb1—O2v108.5 (7)Pb2—Sn1—O2iv37.4 (7)
Pb1i—Pb1—O3iii165.7 (10)Pb2—Sn1—O393.6 (7)
Pb2ii—Pb1—Pb2iii146.02 (8)Pb2—Sn1—O3iv130.5 (9)
Pb2ii—Pb1—O2iv62.0 (7)Pb2iv—Sn1—Sn1vii61.86 (3)
Pb2ii—Pb1—O2v151.9 (7)Pb2iv—Sn1—Sn1v118.14 (3)
Pb2ii—Pb1—O3iii92.3 (3)Pb2iv—Sn1—O189.0 (5)
Pb2iii—Pb1—O2iv151.9 (7)Pb2iv—Sn1—O1iv44.0 (6)
Pb2iii—Pb1—O2v62.0 (7)Pb2iv—Sn1—O237.4 (7)
Pb2iii—Pb1—O3iii92.3 (3)Pb2iv—Sn1—O2iv139.6 (7)
O2iv—Pb1—O2v90.0 (10)Pb2iv—Sn1—O3130.5 (9)
O2iv—Pb1—O3iii81.3 (10)Pb2iv—Sn1—O3iv93.6 (7)
O2v—Pb1—O3iii81.3 (10)Sn1vii—Sn1—Sn1v180.0 (5)
Pb1viii—Pb2—Pb1ix146.02 (8)Sn1vii—Sn1—O138.6 (5)
Pb1viii—Pb2—Pb2vi86.99 (4)Sn1vii—Sn1—O1iv38.6 (5)
Pb1viii—Pb2—Sn1115.87 (5)Sn1vii—Sn1—O288.0 (5)
Pb1viii—Pb2—Sn1vii62.25 (4)Sn1vii—Sn1—O2iv88.0 (5)
Pb1viii—Pb2—O182.24 (16)Sn1vii—Sn1—O3139.0 (8)
Pb1viii—Pb2—O1ii105.96 (7)Sn1vii—Sn1—O3iv139.0 (8)
Pb1viii—Pb2—O2iv142.1 (6)Sn1v—Sn1—O1141.4 (5)
Pb1viii—Pb2—O2vii56.2 (7)Sn1v—Sn1—O1iv141.4 (5)
Pb1ix—Pb2—Pb2vi86.99 (4)Sn1v—Sn1—O292.0 (5)
Pb1ix—Pb2—Sn162.25 (4)Sn1v—Sn1—O2iv92.0 (5)
Pb1ix—Pb2—Sn1vii115.87 (5)Sn1v—Sn1—O341.0 (8)
Pb1ix—Pb2—O182.24 (16)Sn1v—Sn1—O3iv41.0 (8)
Pb1ix—Pb2—O1ii105.96 (7)O1—Sn1—O1iv77.1 (7)
Pb1ix—Pb2—O2iv56.2 (7)O1—Sn1—O295.6 (9)
Pb1ix—Pb2—O2vii142.1 (6)O1—Sn1—O2iv81.2 (9)
Pb2vi—Pb2—Sn1148.99 (4)O1—Sn1—O3100.8 (9)
Pb2vi—Pb2—Sn1vii148.99 (4)O1—Sn1—O3iv173.7 (12)
Pb2vi—Pb2—O1142.1 (6)O1iv—Sn1—O281.2 (9)
Pb2vi—Pb2—O1ii80.6 (5)O1iv—Sn1—O2iv95.6 (9)
Pb2vi—Pb2—O2iv130.6 (7)O1iv—Sn1—O3173.7 (12)
Pb2vi—Pb2—O2vii130.6 (7)O1iv—Sn1—O3iv100.8 (9)
Sn1—Pb2—Sn1vii56.28 (4)O2—Sn1—O2iv176.0 (8)
Sn1—Pb2—O136.5 (4)O2—Sn1—O393.1 (12)
Sn1—Pb2—O1ii110.2 (4)O2—Sn1—O3iv89.9 (12)
Sn1—Pb2—O2iv33.8 (8)O2iv—Sn1—O389.9 (12)
Sn1—Pb2—O2vii80.4 (7)O2iv—Sn1—O3iv93.1 (12)
Sn1vii—Pb2—O136.5 (4)O3—Sn1—O3iv81.9 (11)
Sn1vii—Pb2—O1ii110.2 (4)Pb2—O1—Pb2viii100.9 (7)
Sn1vii—Pb2—O2iv80.4 (7)Pb2—O1—Sn199.5 (8)
Sn1vii—Pb2—O2vii33.8 (8)Pb2—O1—Sn1vii99.5 (8)
O1—Pb2—O1ii137.3 (8)Pb2viii—O1—Sn1124.0 (7)
O1—Pb2—O2iv70.2 (9)Pb2viii—O1—Sn1vii124.0 (7)
O1—Pb2—O2vii70.2 (9)Sn1—O1—Sn1vii102.9 (10)
O1ii—Pb2—O2iv80.0 (9)Pb1iv—O2—Pb2iv142.0 (14)
O1ii—Pb2—O2vii80.0 (9)Pb1iv—O2—Sn1109.1 (11)
O2iv—Pb2—O2vii89.4 (9)Pb2iv—O2—Sn1108.8 (13)
Pb2—Sn1—Pb2iv123.72 (6)Pb1ix—O3—Sn1106.6 (12)
Pb2—Sn1—Sn1vii61.86 (3)Pb1ix—O3—Sn1v106.6 (12)
Pb2—Sn1—Sn1v118.14 (3)Sn1—O3—Sn1v98.1 (16)
Symmetry codes: (i) −x+1, −y, z; (ii) −x+1/2, y−1/2, −z−1; (iii) −x+1/2, y−1/2, −z; (iv) −x+1, −y+1, z; (v) −x+1, −y+1, −z; (vi) −x, −y+1, z; (vii) −x+1, −y+1, −z−1; (viii) −x+1/2, y+1/2, −z−1; (ix) −x+1/2, y+1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P4) top
Crystal data top
O4Pb2SnDx = 10.056 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PbamCell parameters from 1004 reflections
a = 9.3169 (6) Åθ = 2.0–18°
b = 6.6337 (6) ŵ = 11.50 mm−1
c = 6.3808 (2) ÅT = 293 K
V = 394.37 (5) Å3Cuboid, colourless
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		1004 independent reflections
Radiation source: synchrotron882 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.074
ω scansθmax = 18°, θmin = 2.0°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −16→19
Tmin = 0.007, Tmax = 0.015k = −11→8
2357 measured reflectionsl = −13→13
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.139Secondary atom site location: difference Fourier map
wR(F2) = 0.188Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 5.97(Δ/σ)max = 0.011
1004 reflectionsΔρmax = 5.62 e Å−3
26 parametersΔρmin = −5.95 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 260 (150)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.3249 (2)0.0880 (4)00.0118 (6)
Pb20.1744 (2)0.4897 (4)−0.50.0134 (6)
Sn10.50.5−0.2414 (4)0.0077 (5)*
O10.410 (4)0.661 (8)−0.50.013 (6)*
O20.688 (4)0.651 (8)−0.256 (5)0.024 (7)*
O30.419 (9)0.691 (16)00.048 (18)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.0119 (9)0.0113 (15)0.0121 (6)−0.0005 (5)00
Pb20.0101 (9)0.0147 (15)0.0155 (7)0.0009 (5)00
Geometric parameters (Å, º) top
Pb1—Pb1i3.466 (3)Pb2—Pb2iv3.603 (4)
Pb1—Pb1ii3.598 (4)Pb2—Pb2ix3.603 (4)
Pb1—Pb1iii3.598 (4)Pb2—Sn13.454 (2)
Pb1—Pb2iv3.2564 (8)Pb2—Sn1x3.454 (2)
Pb1—Pb2ii3.2564 (8)Pb2—O1iv2.32 (5)
Pb1—Sn1ii3.446 (2)Pb2—O2vi2.22 (4)
Pb1—Sn1v3.446 (2)Pb2—O2x2.22 (4)
Pb1—O2vi2.38 (4)Sn1—Sn1x3.300 (4)
Pb1—O2vii2.38 (4)Sn1—Sn1vii3.081 (4)
Pb1—O3ii2.37 (9)Sn1—O22.02 (4)
Pb2—Pb2viii3.253 (3)Sn1—O2vi2.02 (4)
Pb1i—Pb1—Pb1ii93.14 (8)Pb1iii—Pb2—O2x140.3 (9)
Pb1i—Pb1—Pb1iii132.51 (9)Pb2viii—Pb2—Pb2iv115.42 (9)
Pb1i—Pb1—Pb2iv86.02 (5)Pb2viii—Pb2—Pb2ix110.61 (9)
Pb1i—Pb1—Pb2ii86.02 (5)Pb2viii—Pb2—Sn1151.25 (4)
Pb1i—Pb1—Sn1ii140.35 (7)Pb2viii—Pb2—Sn1x151.25 (4)
Pb1i—Pb1—Sn1v140.35 (7)Pb2viii—Pb2—O1iv72.6 (10)
Pb1i—Pb1—O2vi107.0 (9)Pb2viii—Pb2—O2vi126.4 (10)
Pb1i—Pb1—O2vii107.0 (9)Pb2viii—Pb2—O2x126.4 (10)
Pb1i—Pb1—O3ii177 (3)Pb2iv—Pb2—Pb2ix133.97 (7)
Pb1ii—Pb1—Pb1iii134.35 (7)Pb2iv—Pb2—Sn171.02 (5)
Pb1ii—Pb1—Pb2iv79.41 (6)Pb2iv—Pb2—Sn1x71.02 (5)
Pb1ii—Pb1—Pb2ii79.41 (6)Pb2iv—Pb2—O1iv42.8 (10)
Pb1ii—Pb1—Sn1ii60.21 (5)Pb2iv—Pb2—O2vi52.3 (12)
Pb1ii—Pb1—Sn1v60.21 (5)Pb2iv—Pb2—O2x52.3 (12)
Pb1ii—Pb1—O2vi130.5 (10)Pb2ix—Pb2—Sn168.80 (5)
Pb1ii—Pb1—O2vii130.5 (10)Pb2ix—Pb2—Sn1x68.80 (5)
Pb1ii—Pb1—O3ii84 (3)Pb2ix—Pb2—O1iv176.8 (10)
Pb1iii—Pb1—Pb2iv100.68 (6)Pb2ix—Pb2—O2vi99.3 (13)
Pb1iii—Pb1—Pb2ii100.68 (6)Pb2ix—Pb2—O2x99.3 (13)
Pb1iii—Pb1—Sn1ii79.36 (5)Sn1—Pb2—Sn1x57.07 (6)
Pb1iii—Pb1—Sn1v79.36 (5)Sn1—Pb2—O1iv108.5 (8)
Pb1iii—Pb1—O2vi46.4 (10)Sn1—Pb2—O2vi33.6 (12)
Pb1iii—Pb1—O2vii46.4 (10)Sn1—Pb2—O2x80.6 (9)
Pb1iii—Pb1—O3ii50 (3)Sn1x—Pb2—O1iv108.5 (8)
Pb2iv—Pb1—Pb2ii156.90 (11)Sn1x—Pb2—O2vi80.6 (9)
Pb2iv—Pb1—Sn1ii113.94 (7)Sn1x—Pb2—O2x33.6 (12)
Pb2iv—Pb1—Sn1v61.96 (5)O1iv—Pb2—O2vi78.5 (15)
Pb2iv—Pb1—O2vi58.3 (10)O1iv—Pb2—O2x78.5 (15)
Pb2iv—Pb1—O2vii144.8 (10)O2vi—Pb2—O2x88.9 (14)
Pb2iv—Pb1—O3ii93.4 (5)Pb1iii—Sn1—Pb1xi126.90 (8)
Pb2ii—Pb1—Sn1ii61.96 (5)Pb1iii—Sn1—Pb256.32 (2)
Pb2ii—Pb1—Sn1v113.94 (7)Pb1iii—Sn1—Pb2vi169.00 (6)
Pb2ii—Pb1—O2vi144.8 (10)Pb1iii—Sn1—Sn1x116.55 (4)
Pb2ii—Pb1—O2vii58.3 (10)Pb1iii—Sn1—Sn1vii63.45 (4)
Pb2ii—Pb1—O3ii93.4 (5)Pb1iii—Sn1—O2134.3 (13)
Sn1ii—Pb1—Sn1v53.10 (6)Pb1iii—Sn1—O2vi48.9 (12)
Sn1ii—Pb1—O2vi112.6 (9)Pb1xi—Sn1—Pb2169.00 (6)
Sn1ii—Pb1—O2vii76.8 (9)Pb1xi—Sn1—Pb2vi56.32 (2)
Sn1ii—Pb1—O3ii37.6 (17)Pb1xi—Sn1—Sn1x116.55 (4)
Sn1v—Pb1—O2vi76.8 (9)Pb1xi—Sn1—Sn1vii63.45 (4)
Sn1v—Pb1—O2vii112.6 (9)Pb1xi—Sn1—O248.9 (12)
Sn1v—Pb1—O3ii37.6 (17)Pb1xi—Sn1—O2vi134.3 (13)
O2vi—Pb1—O2vii86.5 (15)Pb2—Sn1—Pb2vi122.93 (8)
O2vi—Pb1—O3ii75 (2)Pb2—Sn1—Sn1x61.46 (4)
O2vii—Pb1—O3ii75 (2)Pb2—Sn1—Sn1vii118.54 (4)
Pb1ix—Pb2—Pb1iii156.90 (11)Pb2—Sn1—O2138.5 (11)
Pb1ix—Pb2—Pb2viii89.63 (5)Pb2—Sn1—O2vi37.5 (12)
Pb1ix—Pb2—Pb2iv100.57 (6)Pb2vi—Sn1—Sn1x61.46 (4)
Pb1ix—Pb2—Pb2ix79.33 (6)Pb2vi—Sn1—Sn1vii118.54 (4)
Pb1ix—Pb2—Sn1117.54 (7)Pb2vi—Sn1—O237.5 (12)
Pb1ix—Pb2—Sn1x61.72 (5)Pb2vi—Sn1—O2vi138.5 (11)
Pb1ix—Pb2—O1iv100.90 (9)Sn1x—Sn1—Sn1vii180.0 (5)
Pb1ix—Pb2—O2vi140.3 (9)Sn1x—Sn1—O287.4 (9)
Pb1ix—Pb2—O2x52.9 (11)Sn1x—Sn1—O2vi87.4 (9)
Pb1iii—Pb2—Pb2viii89.63 (5)Sn1vii—Sn1—O292.6 (9)
Pb1iii—Pb2—Pb2iv100.57 (6)Sn1vii—Sn1—O2vi92.6 (9)
Pb1iii—Pb2—Pb2ix79.33 (6)O2—Sn1—O2vi174.7 (13)
Pb1iii—Pb2—Sn161.72 (5)Pb1vi—O2—Pb2vi145 (2)
Pb1iii—Pb2—Sn1x117.54 (7)Pb1vi—O2—Sn1106.6 (15)
Pb1iii—Pb2—O1iv100.90 (9)Pb2vi—O2—Sn1109 (2)
Pb1iii—Pb2—O2vi52.9 (11)
Symmetry codes: (i) −x+1, −y, z; (ii) −x+1/2, y−1/2, −z; (iii) −x+1/2, y+1/2, −z; (iv) −x+1/2, y−1/2, −z−1; (v) x−1/2, −y+1/2, z; (vi) −x+1, −y+1, z; (vii) −x+1, −y+1, −z; (viii) −x, −y+1, z; (ix) −x+1/2, y+1/2, −z−1; (x) −x+1, −y+1, −z−1; (xi) x+1/2, −y+1/2, −z.
Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P5) top
Crystal data top
O4Pb2SnDx = 10.373 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PnamCell parameters from 814 reflections
a = 9.2484 (8) Åθ = 2.0–17.9°
b = 6.4498 (9) ŵ = 11.86 mm−1
c = 6.4096 (2) ÅT = 293 K
V = 382.33 (6) Å3Cuboid, black
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		814 independent reflections
Radiation source: synchrotron735 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.014
ω scansθmax = 17.9°, θmin = 2.0°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −17→16
Tmin = 0.007, Tmax = 0.015k = −8→10
2030 measured reflectionsl = −13→13
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.019Secondary atom site location: difference Fourier map
wR(F2) = 0.024Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.16(Δ/σ)max = 0.010
814 reflectionsΔρmax = 1.13 e Å−3
38 parametersΔρmin = −1.11 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 820 (30)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.325842 (16)0.04839 (4)−0.00841 (2)0.01372 (7)
Sn10.50457 (3)0.48903 (7)0.250.00925 (11)
O10.3216 (4)0.3172 (9)0.250.0136 (16)
O20.7014 (4)0.6250 (8)0.250.0113 (13)
O30.4177 (3)0.6679 (7)0.4877 (4)0.0111 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.01156 (10)0.01859 (17)0.01101 (6)−0.00029 (4)0.00021 (4)0.00015 (5)
Sn10.00920 (16)0.0102 (3)0.00836 (10)−0.00039 (9)00
O10.015 (2)0.014 (4)0.0119 (11)−0.0022 (12)00
O20.0111 (19)0.011 (3)0.0119 (11)−0.0015 (11)00
O30.0113 (14)0.012 (2)0.0104 (8)0.0005 (8)0.0007 (8)0.0006 (10)
Geometric parameters (Å, º) top
Pb1—Pb1i3.5185 (9)Pb1—O3vii2.381 (3)
Pb1—Pb1ii3.5185 (9)Sn1—Sn1viii3.2090 (2)
Pb1—Pb1iii3.2831 (6)Sn1—Sn1ix3.2090 (2)
Pb1—Pb1iv3.0970 (3)Sn1—O12.023 (4)
Pb1—Pb1v3.3126 (3)Sn1—O22.021 (4)
Pb1—Sn1i3.4471 (6)Sn1—O32.073 (3)
Pb1—Sn1vi3.4103 (5)Sn1—O3viii2.090 (3)
Pb1—O12.398 (4)Sn1—O3x2.090 (3)
Pb1—O2vi2.306 (3)Sn1—O3v2.073 (3)
Pb1i—Pb1—Pb1ii132.858 (9)Pb1xi—Sn1—O1133.64 (11)
Pb1i—Pb1—Pb1iii102.471 (10)Pb1xi—Sn1—O241.04 (9)
Pb1i—Pb1—Pb1iv91.756 (7)Pb1xi—Sn1—O391.15 (8)
Pb1i—Pb1—Pb1v88.244 (7)Pb1xi—Sn1—O3viii93.25 (8)
Pb1i—Pb1—Sn1i63.801 (9)Pb1xi—Sn1—O3x43.56 (9)
Pb1i—Pb1—Sn1vi64.715 (9)Pb1xi—Sn1—O3v137.22 (9)
Pb1i—Pb1—O1129.42 (9)Pb1xii—Sn1—Pb1xiii176.766 (12)
Pb1i—Pb1—O2vi48.28 (10)Pb1xii—Sn1—Sn1viii62.679 (7)
Pb1i—Pb1—O3vii85.40 (11)Pb1xii—Sn1—Sn1ix120.738 (9)
Pb1ii—Pb1—Pb1iii124.366 (9)Pb1xii—Sn1—O1133.64 (11)
Pb1ii—Pb1—Pb1iv91.756 (7)Pb1xii—Sn1—O241.04 (9)
Pb1ii—Pb1—Pb1v88.244 (7)Pb1xii—Sn1—O3137.22 (9)
Pb1ii—Pb1—Sn1i76.238 (10)Pb1xii—Sn1—O3viii43.56 (9)
Pb1ii—Pb1—Sn1vi72.699 (10)Pb1xii—Sn1—O3x93.25 (8)
Pb1ii—Pb1—O146.34 (9)Pb1xii—Sn1—O3v91.15 (8)
Pb1ii—Pb1—O2vi102.91 (12)Pb1xiii—Sn1—Sn1viii114.859 (9)
Pb1ii—Pb1—O3vii47.65 (11)Pb1xiii—Sn1—Sn1ix61.518 (7)
Pb1iii—Pb1—Pb1iv91.882 (5)Pb1xiii—Sn1—O147.10 (12)
Pb1iii—Pb1—Pb1v88.118 (5)Pb1xiii—Sn1—O2138.63 (10)
Pb1iii—Pb1—Sn1i149.708 (9)Pb1xiii—Sn1—O342.65 (9)
Pb1iii—Pb1—Sn1vi145.638 (8)Pb1xiii—Sn1—O3viii136.06 (8)
Pb1iii—Pb1—O197.52 (9)Pb1xiii—Sn1—O3x89.85 (8)
Pb1iii—Pb1—O2vi111.96 (9)Pb1xiii—Sn1—O3v85.69 (8)
Pb1iii—Pb1—O3vii171.97 (10)Sn1viii—Sn1—Sn1ix174.111 (18)
Pb1iv—Pb1—Pb1v180.0 (5)Sn1viii—Sn1—O190.122 (11)
Pb1iv—Pb1—Sn1i63.306 (5)Sn1viii—Sn1—O290.263 (11)
Pb1iv—Pb1—Sn1vi119.057 (6)Sn1viii—Sn1—O3134.36 (10)
Pb1iv—Pb1—O1133.68 (10)Sn1viii—Sn1—O3viii39.38 (10)
Pb1iv—Pb1—O2vi135.91 (8)Sn1viii—Sn1—O3x146.49 (10)
Pb1iv—Pb1—O3vii89.40 (6)Sn1viii—Sn1—O3v39.76 (10)
Pb1v—Pb1—Sn1i116.694 (6)Sn1ix—Sn1—O190.122 (11)
Pb1v—Pb1—Sn1vi60.943 (5)Sn1ix—Sn1—O290.263 (11)
Pb1v—Pb1—O146.32 (10)Sn1ix—Sn1—O339.76 (10)
Pb1v—Pb1—O2vi44.09 (8)Sn1ix—Sn1—O3viii146.49 (10)
Pb1v—Pb1—O3vii90.60 (6)Sn1ix—Sn1—O3x39.38 (10)
Sn1i—Pb1—Sn1vi55.802 (6)Sn1ix—Sn1—O3v134.36 (10)
Sn1i—Pb1—O1112.09 (9)O1—Sn1—O2172.5 (2)
Sn1i—Pb1—O2vi80.00 (8)O1—Sn1—O388.89 (14)
Sn1i—Pb1—O3vii36.15 (8)O1—Sn1—O3viii91.28 (13)
Sn1vi—Pb1—O172.63 (9)O1—Sn1—O3x91.28 (13)
Sn1vi—Pb1—O2vi35.12 (10)O1—Sn1—O3v88.89 (14)
Sn1vi—Pb1—O3vii37.22 (8)O2—Sn1—O396.18 (13)
O1—Pb1—O2vi81.16 (14)O2—Sn1—O3viii84.28 (12)
O1—Pb1—O3vii75.98 (12)O2—Sn1—O3x84.28 (12)
O2vi—Pb1—O3vii72.08 (13)O2—Sn1—O3v96.18 (13)
Pb1ii—Sn1—Pb1xi176.766 (12)O3—Sn1—O3viii173.74 (14)
Pb1ii—Sn1—Pb1xii124.198 (5)O3—Sn1—O3x79.14 (14)
Pb1ii—Sn1—Pb1xiii53.388 (7)O3—Sn1—O3v94.60 (14)
Pb1ii—Sn1—Sn1viii61.518 (7)O3viii—Sn1—O3x107.11 (14)
Pb1ii—Sn1—Sn1ix114.859 (9)O3viii—Sn1—O3v79.14 (14)
Pb1ii—Sn1—O147.10 (12)O3x—Sn1—O3v173.74 (14)
Pb1ii—Sn1—O2138.63 (10)Pb1—O1—Pb1v87.37 (19)
Pb1ii—Sn1—O385.69 (8)Pb1—O1—Sn1112.48 (13)
Pb1ii—Sn1—O3viii89.85 (8)Pb1v—O1—Sn1112.48 (13)
Pb1ii—Sn1—O3x136.06 (8)Pb1xi—O2—Pb1xii91.81 (16)
Pb1ii—Sn1—O3v42.65 (9)Pb1xi—O2—Sn1103.83 (17)
Pb1xi—Sn1—Pb1xii58.114 (7)Pb1xii—O2—Sn1103.83 (17)
Pb1xi—Sn1—Pb1xiii124.198 (5)Pb1xiii—O3—Sn1101.20 (15)
Pb1xi—Sn1—Sn1viii120.738 (9)Pb1xiii—O3—Sn1ix99.22 (14)
Pb1xi—Sn1—Sn1ix62.679 (7)Sn1—O3—Sn1ix100.86 (17)
Symmetry codes: (i) −x+1/2, y−1/2, −z; (ii) −x+1/2, y+1/2, −z; (iii) −x+1, −y, −z; (iv) x, y, −z−1/2; (v) x, y, −z+1/2; (vi) x−1/2, −y+1/2, −z+1/2; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1, −y+1, z−1/2; (ix) −x+1, −y+1, z+1/2; (x) −x+1, −y+1, −z+1; (xi) x+1/2, −y+1/2, −z+1/2; (xii) x+1/2, −y+1/2, z; (xiii) −x+1/2, y+1/2, z+1/2.
Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P6) top
Crystal data top
O4Pb2SnDx = 10.582 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PnamCell parameters from 814 reflections
a = 9.1830 (6) Åθ = 2.1–18.1°
b = 6.4046 (6) ŵ = 12.10 mm−1
c = 6.3727 (2) ÅT = 293 K
V = 374.80 (4) Å3Cuboid, black
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		814 independent reflections
Radiation source: synchrotron710 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.016
ω scansθmax = 18.1°, θmin = 2.1°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −17→16
Tmin = 0.007, Tmax = 0.015k = −8→9
1973 measured reflectionsl = −13→12
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.020Secondary atom site location: difference Fourier map
wR(F2) = 0.028Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.35(Δ/σ)max = 0.019
814 reflectionsΔρmax = 0.55 e Å−3
38 parametersΔρmin = −0.98 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 350 (30)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.32743 (2)0.04860 (4)−0.00895 (3)0.01368 (8)
Sn10.50478 (4)0.48900 (9)0.250.01019 (14)
O10.3213 (5)0.3176 (11)0.250.0119 (18)
O20.7025 (5)0.6253 (10)0.250.0110 (17)
O30.4171 (4)0.6684 (8)0.4877 (5)0.0120 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.01159 (12)0.0170 (2)0.01240 (8)−0.00029 (4)0.00023 (5)0.00012 (6)
Sn10.0095 (2)0.0113 (4)0.00980 (13)−0.00047 (11)00
O10.015 (3)0.007 (4)0.0138 (15)−0.0021 (13)00
O20.013 (2)0.007 (4)0.0131 (15)−0.0008 (13)00
O30.0156 (18)0.008 (3)0.0128 (11)0.0016 (10)−0.0002 (10)−0.0006 (14)
Geometric parameters (Å, º) top
Pb1—Pb1i3.5057 (7)Pb1—O3vii2.373 (4)
Pb1—Pb1ii3.5057 (7)Sn1—Sn1viii3.1907 (2)
Pb1—Pb1iii3.2320 (5)Sn1—Sn1ix3.1907 (2)
Pb1—Pb1iv3.0723 (3)Sn1—O12.011 (5)
Pb1—Pb1v3.3004 (3)Sn1—O22.015 (5)
Pb1—Sn1i3.4369 (5)Sn1—O32.065 (4)
Pb1—Sn1vi3.4000 (5)Sn1—O3viii2.080 (4)
Pb1—O12.386 (5)Sn1—O3x2.080 (4)
Pb1—O2vi2.298 (4)Sn1—O3v2.065 (4)
Pb1i—Pb1—Pb1ii131.973 (9)Pb1xi—Sn1—O1133.75 (14)
Pb1i—Pb1—Pb1iii102.750 (9)Pb1xi—Sn1—O241.00 (12)
Pb1i—Pb1—Pb1iv91.865 (8)Pb1xi—Sn1—O391.33 (10)
Pb1i—Pb1—Pb1v88.135 (7)Pb1xi—Sn1—O3viii93.16 (10)
Pb1i—Pb1—Sn1i63.450 (11)Pb1xi—Sn1—O3x43.53 (11)
Pb1i—Pb1—Sn1vi64.279 (11)Pb1xi—Sn1—O3v137.34 (11)
Pb1i—Pb1—O1128.86 (12)Pb1xii—Sn1—Pb1xiii176.681 (15)
Pb1i—Pb1—O2vi48.04 (13)Pb1xii—Sn1—Sn1viii62.768 (8)
Pb1i—Pb1—O3vii84.94 (12)Pb1xii—Sn1—Sn1ix120.784 (12)
Pb1ii—Pb1—Pb1iii124.931 (9)Pb1xii—Sn1—O1133.75 (14)
Pb1ii—Pb1—Pb1iv91.865 (8)Pb1xii—Sn1—O241.00 (12)
Pb1ii—Pb1—Pb1v88.135 (7)Pb1xii—Sn1—O3137.34 (11)
Pb1ii—Pb1—Sn1i75.873 (11)Pb1xii—Sn1—O3viii43.53 (11)
Pb1ii—Pb1—Sn1vi72.266 (11)Pb1xii—Sn1—O3x93.16 (10)
Pb1ii—Pb1—O146.25 (11)Pb1xii—Sn1—O3v91.33 (10)
Pb1ii—Pb1—O2vi102.52 (15)Pb1xiii—Sn1—Sn1viii114.647 (12)
Pb1ii—Pb1—O3vii47.24 (12)Pb1xiii—Sn1—Sn1ix61.596 (8)
Pb1iii—Pb1—Pb1iv92.023 (7)Pb1xiii—Sn1—O146.91 (14)
Pb1iii—Pb1—Pb1v87.977 (7)Pb1xiii—Sn1—O2138.75 (13)
Pb1iii—Pb1—Sn1i149.863 (10)Pb1xiii—Sn1—O342.62 (11)
Pb1iii—Pb1—Sn1vi145.467 (10)Pb1xiii—Sn1—O3viii135.99 (11)
Pb1iii—Pb1—O197.92 (11)Pb1xiii—Sn1—O3x90.04 (10)
Pb1iii—Pb1—O2vi111.77 (12)Pb1xiii—Sn1—O3v85.41 (10)
Pb1iii—Pb1—O3vii172.10 (12)Sn1viii—Sn1—Sn1ix174.04 (2)
Pb1iv—Pb1—Pb1v180.0 (5)Sn1viii—Sn1—O190.060 (15)
Pb1iv—Pb1—Sn1i63.451 (6)Sn1viii—Sn1—O290.324 (14)
Pb1iv—Pb1—Sn1vi119.036 (8)Sn1viii—Sn1—O3134.22 (12)
Pb1iv—Pb1—O1133.75 (12)Sn1viii—Sn1—O3viii39.49 (12)
Pb1iv—Pb1—O2vi135.90 (10)Sn1viii—Sn1—O3x146.47 (12)
Pb1iv—Pb1—O3vii89.48 (8)Sn1viii—Sn1—O3v39.83 (11)
Pb1v—Pb1—Sn1i116.549 (7)Sn1ix—Sn1—O190.060 (15)
Pb1v—Pb1—Sn1vi60.964 (6)Sn1ix—Sn1—O290.324 (14)
Pb1v—Pb1—O146.25 (12)Sn1ix—Sn1—O339.83 (11)
Pb1v—Pb1—O2vi44.10 (10)Sn1ix—Sn1—O3viii146.47 (12)
Pb1v—Pb1—O3vii90.52 (8)Sn1ix—Sn1—O3x39.49 (12)
Sn1i—Pb1—Sn1vi55.636 (6)Sn1ix—Sn1—O3v134.22 (12)
Sn1i—Pb1—O1111.61 (11)O1—Sn1—O2172.6 (3)
Sn1i—Pb1—O2vi79.86 (9)O1—Sn1—O388.68 (17)
Sn1i—Pb1—O3vii36.10 (10)O1—Sn1—O3viii91.40 (16)
Sn1vi—Pb1—O172.24 (11)O1—Sn1—O3x91.40 (16)
Sn1vi—Pb1—O2vi35.12 (13)O1—Sn1—O3v88.68 (17)
Sn1vi—Pb1—O3vii37.12 (9)O2—Sn1—O396.33 (16)
O1—Pb1—O2vi80.88 (17)O2—Sn1—O3viii84.21 (15)
O1—Pb1—O3vii75.55 (15)O2—Sn1—O3x84.21 (15)
O2vi—Pb1—O3vii71.99 (16)O2—Sn1—O3v96.33 (16)
Pb1ii—Sn1—Pb1xi176.680 (15)O3—Sn1—O3viii173.70 (17)
Pb1ii—Sn1—Pb1xii124.364 (6)O3—Sn1—O3x79.31 (16)
Pb1ii—Sn1—Pb1xiii53.097 (8)O3—Sn1—O3v94.39 (16)
Pb1ii—Sn1—Sn1viii61.596 (8)O3viii—Sn1—O3x106.98 (17)
Pb1ii—Sn1—Sn1ix114.647 (12)O3viii—Sn1—O3v79.31 (16)
Pb1ii—Sn1—O146.91 (14)O3x—Sn1—O3v173.70 (17)
Pb1ii—Sn1—O2138.75 (13)Pb1—O1—Pb1v87.5 (2)
Pb1ii—Sn1—O385.41 (10)Pb1—O1—Sn1111.98 (16)
Pb1ii—Sn1—O3viii90.04 (10)Pb1v—O1—Sn1111.98 (16)
Pb1ii—Sn1—O3x135.99 (11)Pb1xi—O2—Pb1xii91.8 (2)
Pb1ii—Sn1—O3v42.62 (11)Pb1xi—O2—Sn1103.9 (2)
Pb1xi—Sn1—Pb1xii58.072 (8)Pb1xii—O2—Sn1103.9 (2)
Pb1xi—Sn1—Pb1xiii124.364 (6)Pb1xiii—O3—Sn1101.28 (17)
Pb1xi—Sn1—Sn1viii120.784 (12)Pb1xiii—O3—Sn1ix99.35 (16)
Pb1xi—Sn1—Sn1ix62.768 (8)Sn1—O3—Sn1ix100.7 (2)
Symmetry codes: (i) −x+1/2, y−1/2, −z; (ii) −x+1/2, y+1/2, −z; (iii) −x+1, −y, −z; (iv) x, y, −z−1/2; (v) x, y, −z+1/2; (vi) x−1/2, −y+1/2, −z+1/2; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1, −y+1, z−1/2; (ix) −x+1, −y+1, z+1/2; (x) −x+1, −y+1, −z+1; (xi) x+1/2, −y+1/2, −z+1/2; (xii) x+1/2, −y+1/2, z; (xiii) −x+1/2, y+1/2, z+1/2.
Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P7) top
Crystal data top
O4Pb2SnDx = 10.950 Mg m−3
Mr = 597.11Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, PnamCell parameters from 813 reflections
a = 9.0691 (6) Åθ = 1.6–17.8°
b = 6.3282 (6) ŵ = 12.52 mm−1
c = 6.3110 (2) ÅT = 293 K
V = 362.20 (4) Å3Cuboid, black
Z = 40.08 × 0.04 × 0.03 mm
F(000) = 984
Data collection top
Esperanto-CrysAlisPro-abstract goniometer imported esperanto images
diffractometer		813 independent reflections
Radiation source: synchrotron709 reflections with I > 3σ(I)
Synchrotron monochromatorRint = 0.017
ω scansθmax = 17.8°, θmin = 1.6°
Absorption correction: empirical (using intensity measurements)
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.		h = −17→16
Tmin = 0.007, Tmax = 0.015k = −9→8
1940 measured reflectionsl = −12→12
Refinement top
Refinement on FPrimary atom site location: heavy-atom method
R[F2 > 2σ(F2)] = 0.024Secondary atom site location: difference Fourier map
wR(F2) = 0.030Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 1.41(Δ/σ)max = 0.003
813 reflectionsΔρmax = 0.64 e Å−3
38 parametersΔρmin = −0.71 e Å−3
0 restraintsExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraintsExtinction coefficient: 330 (40)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pb10.329942 (19)0.04924 (4)−0.01000 (3)0.01364 (8)
Sn10.50515 (4)0.48897 (9)0.250.01117 (14)
O10.3188 (5)0.3174 (11)0.250.0130 (18)
O20.7045 (6)0.6259 (10)0.250.0141 (18)
O30.4172 (4)0.6707 (8)0.4877 (5)0.0128 (12)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.01235 (12)0.0159 (2)0.01263 (8)−0.00023 (4)0.00012 (4)0.00002 (6)
Sn10.0107 (2)0.0129 (4)0.00992 (13)−0.00042 (12)00
O10.014 (2)0.013 (4)0.0121 (14)−0.0022 (14)00
O20.014 (3)0.014 (4)0.0142 (16)−0.0011 (14)00
O30.0140 (17)0.012 (3)0.0122 (10)0.0023 (10)0.0014 (9)0.0012 (12)
Geometric parameters (Å, º) top
Pb1—Pb1i3.4825 (6)Pb1—O3vii2.369 (4)
Pb1—Pb1ii3.4825 (6)Sn1—Sn1viii3.1600 (2)
Pb1—Pb1iii3.1493 (5)Sn1—Sn1ix3.1600 (2)
Pb1—Pb1iv3.0293 (3)Sn1—O12.009 (5)
Pb1—Pb1v3.2817 (3)Sn1—O22.005 (6)
Pb1—Sn1i3.4168 (5)Sn1—O32.052 (4)
Pb1—Sn1vi3.3804 (5)Sn1—O3viii2.063 (4)
Pb1—O12.363 (5)Sn1—O3x2.063 (4)
Pb1—O2vi2.284 (4)Sn1—O3v2.052 (4)
Pb1i—Pb1—Pb1ii130.592 (8)Pb1xi—Sn1—O1133.98 (13)
Pb1i—Pb1—Pb1iii103.095 (9)Pb1xi—Sn1—O240.99 (12)
Pb1i—Pb1—Pb1iv92.077 (8)Pb1xi—Sn1—O391.37 (10)
Pb1i—Pb1—Pb1v87.923 (7)Pb1xi—Sn1—O3viii93.27 (10)
Pb1i—Pb1—Sn1i62.894 (10)Pb1xi—Sn1—O3x43.79 (11)
Pb1i—Pb1—Sn1vi63.553 (11)Pb1xi—Sn1—O3v137.21 (11)
Pb1i—Pb1—O1127.55 (12)Pb1xii—Sn1—Pb1xiii176.511 (14)
Pb1i—Pb1—O2vi47.60 (13)Pb1xii—Sn1—Sn1viii62.883 (8)
Pb1i—Pb1—O3vii84.32 (12)Pb1xii—Sn1—Sn1ix120.907 (12)
Pb1ii—Pb1—Pb1iii125.880 (9)Pb1xii—Sn1—O1133.98 (13)
Pb1ii—Pb1—Pb1iv92.077 (8)Pb1xii—Sn1—O240.99 (12)
Pb1ii—Pb1—Pb1v87.923 (7)Pb1xii—Sn1—O3137.21 (11)
Pb1ii—Pb1—Sn1i75.354 (11)Pb1xii—Sn1—O3viii43.79 (11)
Pb1ii—Pb1—Sn1vi71.614 (11)Pb1xii—Sn1—O3x93.27 (10)
Pb1ii—Pb1—O145.94 (11)Pb1xii—Sn1—O3v91.37 (10)
Pb1ii—Pb1—O2vi101.97 (15)Pb1xiii—Sn1—Sn1viii114.295 (12)
Pb1ii—Pb1—O3vii46.51 (12)Pb1xiii—Sn1—Sn1ix61.713 (8)
Pb1iii—Pb1—Pb1iv92.297 (7)Pb1xiii—Sn1—O146.53 (14)
Pb1iii—Pb1—Pb1v87.703 (6)Pb1xiii—Sn1—O2138.92 (13)
Pb1iii—Pb1—Sn1i150.085 (10)Pb1xiii—Sn1—O342.90 (11)
Pb1iii—Pb1—Sn1vi145.066 (10)Pb1xiii—Sn1—O3viii135.55 (11)
Pb1iii—Pb1—O198.98 (11)Pb1xiii—Sn1—O3x90.15 (10)
Pb1iii—Pb1—O2vi111.29 (13)Pb1xiii—Sn1—O3v85.17 (10)
Pb1iii—Pb1—O3vii172.25 (12)Sn1viii—Sn1—Sn1ix173.91 (2)
Pb1iv—Pb1—Pb1v180.0 (5)Sn1viii—Sn1—O189.943 (15)
Pb1iv—Pb1—Sn1i63.686 (6)Sn1viii—Sn1—O290.434 (14)
Pb1iv—Pb1—Sn1vi119.039 (7)Sn1viii—Sn1—O3133.94 (11)
Pb1iv—Pb1—O1133.99 (12)Sn1viii—Sn1—O3viii39.69 (12)
Pb1iv—Pb1—O2vi135.93 (11)Sn1viii—Sn1—O3x146.40 (12)
Pb1iv—Pb1—O3vii89.65 (8)Sn1viii—Sn1—O3v39.97 (11)
Pb1v—Pb1—Sn1i116.314 (7)Sn1ix—Sn1—O189.943 (15)
Pb1v—Pb1—Sn1vi60.961 (6)Sn1ix—Sn1—O290.434 (14)
Pb1v—Pb1—O146.01 (12)Sn1ix—Sn1—O339.97 (11)
Pb1v—Pb1—O2vi44.07 (11)Sn1ix—Sn1—O3viii146.40 (12)
Pb1v—Pb1—O3vii90.35 (8)Sn1ix—Sn1—O3x39.69 (12)
Sn1i—Pb1—Sn1vi55.404 (6)Sn1ix—Sn1—O3v133.94 (11)
Sn1i—Pb1—O1110.49 (11)O1—Sn1—O2172.9 (3)
Sn1i—Pb1—O2vi79.70 (11)O1—Sn1—O388.62 (17)
Sn1i—Pb1—O3vii36.12 (10)O1—Sn1—O3viii91.29 (16)
Sn1vi—Pb1—O171.15 (11)O1—Sn1—O3x91.29 (16)
Sn1vi—Pb1—O2vi35.16 (14)O1—Sn1—O3v88.62 (17)
Sn1vi—Pb1—O3vii37.06 (9)O2—Sn1—O396.22 (17)
O1—Pb1—O2vi80.11 (18)O2—Sn1—O3viii84.48 (15)
O1—Pb1—O3vii74.39 (15)O2—Sn1—O3x84.48 (15)
O2vi—Pb1—O3vii71.98 (17)O2—Sn1—O3v96.22 (17)
Pb1ii—Sn1—Pb1xi176.511 (14)O3—Sn1—O3viii173.64 (16)
Pb1ii—Sn1—Pb1xii124.596 (6)O3—Sn1—O3x79.66 (16)
Pb1ii—Sn1—Pb1xiii52.628 (8)O3—Sn1—O3v93.98 (16)
Pb1ii—Sn1—Sn1viii61.713 (8)O3viii—Sn1—O3x106.70 (17)
Pb1ii—Sn1—Sn1ix114.295 (12)O3viii—Sn1—O3v79.66 (16)
Pb1ii—Sn1—O146.53 (14)O3x—Sn1—O3v173.64 (16)
Pb1ii—Sn1—O2138.92 (13)Pb1—O1—Pb1v88.0 (2)
Pb1ii—Sn1—O385.17 (10)Pb1—O1—Sn1110.62 (16)
Pb1ii—Sn1—O3viii90.15 (10)Pb1v—O1—Sn1110.62 (16)
Pb1ii—Sn1—O3x135.55 (11)Pb1xi—O2—Pb1xii91.9 (2)
Pb1ii—Sn1—O3v42.90 (11)Pb1xi—O2—Sn1103.9 (2)
Pb1xi—Sn1—Pb1xii58.079 (8)Pb1xii—O2—Sn1103.9 (2)
Pb1xi—Sn1—Pb1xiii124.596 (6)Pb1xiii—O3—Sn1100.98 (17)
Pb1xi—Sn1—Sn1viii120.907 (12)Pb1xiii—O3—Sn1ix99.15 (16)
Pb1xi—Sn1—Sn1ix62.883 (8)Sn1—O3—Sn1ix100.3 (2)
Symmetry codes: (i) −x+1/2, y−1/2, −z; (ii) −x+1/2, y+1/2, −z; (iii) −x+1, −y, −z; (iv) x, y, −z−1/2; (v) x, y, −z+1/2; (vi) x−1/2, −y+1/2, −z+1/2; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1, −y+1, z−1/2; (ix) −x+1, −y+1, z+1/2; (x) −x+1, −y+1, −z+1; (xi) x+1/2, −y+1/2, −z+1/2; (xii) x+1/2, −y+1/2, z; (xiii) −x+1/2, y+1/2, z+1/2.
 

Acknowledgements

The `2n+1' Raman theorem in CASTEP was developed under grant EP/I030107/1. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III. Open access funding enabled and organized by Projekt DEAL.

Funding information

Funding for this research was provided by: Deutsche Forschungsgemeinschaft (grant No. Wi1232/44-1; grant No. Wi1232/41-1; grant No. Ba4020; grant No. FOR2125); Bundesministerium für Bildung und Forschung (grant No. 05K16RFB); Engineering and Physical Sciences Research Council (grant No. EP/I030107/1).

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Journal logoSTRUCTURAL SCIENCE
CRYSTAL ENGINEERING
MATERIALS
ISSN: 2052-5206
Volume 76| Part 6| December 2020| Pages 979-991
https://doi.org/10.1107/S205252062001238X
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