Synthesis of new Ln4(Al2O6F2)O2 (Ln = Sm, Eu, Gd) phases with a cuspidine-related structure

Morán-Ruiz, A.; Wain-Martin, A.; Orera, A.; Sanjuán, M.L.; Larrañaga, A.; Slater, P.R.; Arriortua, M.

doi:10.1107/S205225251801744X

research papers

IUCrJ

Volume 6| Part 1| January 2019| Pages 128-135

ISSN: 2052-2525

https://doi.org/10.1107/S205225251801744X

CHEMISTRY | CRYSTENG

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Synthesis of new Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Eu, Gd) phases with a cuspidine-related structure

Aroa Morán-Ruiz,^a ^* Aritza Wain-Martin,^a Alodia Orera,^b María Luisa Sanjuán,^b Aitor Larrañaga,^a Peter R. Slater ^c and Maribel Arriortua ^a,^d ^*

^aUniversidad del País Vasco (UPV/EHU), Facultad de Ciencia y Tecnología, Barrio Sarriena S/N, Leioa, Vizcaya 48940, Spain, ^bInstituto de Ciencia de Materiales de Aragón (CSIC - Universidad de Zaragoza), C/ Pedro Cerbuna 12, Zaragoza 50009, Spain, ^cUniversity of Birmingham, School of Chemistry, Birmingham B15 2TT, UK, and ^dBCMaterials (Basque Centre for Materials, Applications and Nanostructures), Bld. Martina Casiano, 3rd. Floor, UPV/EHU Science Park, Barrio Sarriena S/N, Leioa, Vizcaya 48940, Spain
^*Correspondence e-mail: aroa.moran@ehu.eus, maribel.arriortua@ehu.eus

Edited by C.-Y. Su, Sun Yat-Sen University, China (Received 28 August 2018; accepted 10 December 2018)

The first fluorination of the cuspidine-related phases of Ln₄(Al₂O₇□)O₂ (where Ln = Sm, Eu, Gd) is reported. A low-temperature reaction with poly(vinylidene difluoride) lead to the fluorine being substituted in place of oxygen and inserted into the vacant position between the dialuminate groups. X-ray photoelectron spectroscopy shows the presence of the F 1s photoelectron together with an increase in Al 2p and rare-earth 4d binding energies supporting F incorporation. Energy-dispersive X-ray spectroscopy analyses are consistent with the formula Ln₄(Al₂O₆F₂)O₂, confirming that substitution of one oxygen by two fluoride atoms has been achieved. Rietveld refinements show an expansion in the cell upon fluorination and confirm that the incorporation of fluoride in the Ln₄(Al₂O₇□)O₂ structure results in changes in Al coordination from four to five. Thus, the isolated tetrahedral dialuminate Al₂O₇ groups are converted to chains of distorted square-based pyramids. These structural results are also discussed based on Raman spectra.

Keywords: cuspidine-type rare-earth aluminates; fluorination; X-ray diffraction; poly(vinylidene difluoride); Raman spectroscopy.

CCDC references: 1886577; 1886578

1. Introduction

Minerals belonging to the cuspidine group have the general stoichiometry M₄(Si₂O₇)X₂ (M = divalent cation; X = OH, F, O), with Ca₄(Si₂O₇)(OH,F)₂ being the archetype compound. The cuspidine structure can be described as built up of chains of edge-sharing MO₇/MO₈ polyhedra running parallel to the a axis (in the P2₁/c space group); the tetrahedral disilicate groups (Si₂O₇) interconnect with these ribbons through the vertices. The structural formula of cuspidine is better described as Ca₄(Si₂O₇□)(OH,F)₂ to directly show the vacant position between the disilicate groups. The filling of that position may convert the isolated pyrogroups into infinite chains of distorted trigonal bipyramids (Martín-Sedeño et al., 2004 ).

Other systems also adopt this structural type, including the Ln₄(Al/Ga)₂O₉ (Ln = rare-earth) type phases, which have attracted attention because of their ionic conductivity and thermal stability (Ghosh, 2015 ; Zhou et al., 2014 ; Martín-Sedeño et al., 2006 ; Morán-Ruiz et al., 2018 ). In more recent years, the preparation and characterization of inorganic oxyfluorides have attracted significant interest. Thus, low-temperature fluorination methods can alter chemistry of the precursor oxide in different ways by charge compensation effects (Clemens & Slater, 2013 ). In particular, polymer reagents such as poly(vinylidine fluoride) and poly(tetrafluoroethylene) have been proven to be successful low-temperature fluorinating reagents, following the early work by Slater (2002 ) which illustrates the use of PVDF to prepare Ca₂CuO₂F₂ and Sr₂TiO₃F₂. Since then, a wide range of perovskite and related phases have been successfully fluorinated using this polymer route (Clemens et al., 2014 ; Hancock et al., 2012 ; Berry et al., 2008 ; Heap et al., 2007 ), and the method has been shown to be equally applicable to the fluorination of thin films (Kawahara et al., 2017 ; Katayama et al., 2016 ; Moon et al., 2015 ). This earlier research has mainly focused on the fluorination of transition-metal containing materials, and so here we investigate the potential use for the fluorination of oxide systems that do not contain transition metals. In particular, given the recent studies on oxide ion/proton conductivity in La₄(Ga_2−xTi_xO_7+x/2)O₂, which illustrate the ability of the cuspidine structure to accommodate extra anions (Martín-Sedeño et al., 2005 ), this would appear to be an ideal structure to examine the possible incorporation of fluoride. We have therefore investigated the fluorination of Ln₄(Al₂O₇□)O₂ to give new Ln₄Al₂O_9−xF_2x (Ln = Sm, Eu, Gd) (0 ≤ x ≤ 1) phases. Here we report the results of these first low-temperature fluorination reactions of a range of rare-earth aluminate cuspidine-related phases. The introduction of fluorine (2 F⁻ replacing O²⁻) was achieved through a reaction with poly(vinylidene fluoride) (PVDF) as the fluorinating agent. We investigate the success and effects of fluorination on the starting structure by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ²⁷Al solid-state nuclear magnetic resonance (NMR), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The thermal stability of these samples after fluorination was evaluated in air through thermogravimetric analysis (TGA).

2. Experimental

2.1. Powder preparation

Starting precursor oxides of Ln₄(Al₂O₇□)O₂ (Ln = Sm, Eu, Gd) were prepared by the glycine nitrate combustion route using the appropriate quantities of metals and combustible substance as previously reported by Morán-Ruiz et al. (2018). The introduction of fluorine (2 F⁻ replacing O⁷⁻) into the Ln₄(Al₂O₇□)O₂ structure was achieved through a low-temperature (400°C) reaction with PVDF (Slater, 2002) as the fluorinating agent. Thus, fluorination was achieved by mixing the rare-earth aluminate phase with PVDF in a 1:1 mol ratio (precursor oxide: CH₂CF₂ monomer unit) and heating (80°C h⁻¹) the mixture at 400°C for 12 h in air.

Since poly(tetrafluoroethylene) (PTFE) has also been shown to be a very good fluorinating reagent, we investigated the possibility of fluorination of Eu₄(Al₂O₇□)O₂ with PTFE under the same conditions. This gave similar results to the reaction with PVDF, with an observed expansion in the unit cell consistent with F incorporation.

2.2. Characterization techniques

X-ray powder diffraction patterns were recorded with a Philips X'Pert-Pro diffractometer using graphite-monochromated Cu Kα_1,2 radiation (λ₁ = 1.5406 Å; λ₂ = 1.5443 Å). The compounds were scanned between 15 and 90° (2θ) in 0.026° steps, counting 380 s per step. In addition, a Bruker D8 Advance Vårio diffractometer, equipped with a primary monochromator and a solid SolX detector, with energy discrimination optimized for such radiation (Cu Kα₁, λ₁ = 1.5406 Å), were also used to improve the quality of the XRD data for structure refinement. The overall measuring time was ∼120 h per pattern to have good statistics over the 2θ angular range of 5–100° with a 0.02° step size. The fitting of the measured and calculated pattern structure refinement was carried out using the program FullProf (Rodríguez-Carvajal, 2011 ). Moreover, Atoms62 software (Shape Software, 2005 ) was also used to illustrate the structure.

X-ray photoelectron spectroscopy (XPS) measurements were performed using an XPS spectrometer (SPECS). All XPS spectra were acquired using a monochromatic X-ray source producing Al Kα radiation (hν = 1486.6 eV) and recorded using a Specs Phoibos 150 analyser. An initial analysis of the elements present in the sample was carried out (wide scan: step energy 1 eV, dwell time 0.1 s, pass energy 80 eV) and individual high-resolution spectra were obtained (detail scan: step energy 0.1 eV, dwell time 0.1 s, pass energy 30 eV) with an electron take-off angle of 90°. The binding energies (BEs) were calibrated using the C 1s peak (BE = 284.6 eV) as an internal standard. The spectra were fitted by CasaXPS 2.3.16 software, modelling the properly weighted sum of Gaussian and Lorentzian component curves, after background subtraction according to Shirley.

The ²⁷Al solid-state NMR spectra were recorded on a Bruker Avance III, at 9.4 T under magic angle (MAS) at 14 kHz using a Bruker probe head 4 mm MAS DVT X/Y/H. The ²⁷Al MAS NMR were recorded at 104.27 MHz using a single-pulse sequence with a 4 µs rf pulse (π/2); the relaxation delay was 0.5 s and a total of 20 000 scans were accumulated. The ²⁷Al chemical shifts were calibrated indirectly with Al(NO₃)₃.

For Raman scattering measurements a DILOR XY spectrometer with a CCD detector and 2 cm⁻¹ of spectral resolution was used. The 514.5 nm line of an Ar⁺-ion laser was used as the excitation source, and the power output was kept below 20 mW after verifying that no changes were induced in the samples. A 50× microscope objective lens was used both for excitation and dispersed light collection. Some spectra were also collected in a WITEC Alpha 300M+ spectrometer working with 633 nm excitation. For each material, at least 3–4 representative spectra of different sample zones were recorded.

Thermogravimetric analyses were performed for all compositions on a TA Instruments SDT 2960 simultaneous DSC–TGA balance. The temperature was varied from room temperature up to 900°C at a heating rate of 3°C min⁻¹ in air.

Compositional analysis was performed using an analytical scanning electron microscope (SEM, JEOL JSM-7000 F) with an electron microanalysis probe EDX (Oxford Pentafet energy dispersive X-ray analyzer). Samples were coated with a coal graphite layer (10 nm) deposited by evaporation (Quorum Q150T Sputter Coater) to provide electrical conductivity. Back-scattered electrons were measured at a 20 kV accelerating voltage and 5 × 10⁻⁹ A current. A measurement time of 100 s per point was established for data acquisition. EDX system calibration was performed by measuring the beam current on Ln₄(Al₂O₇□)O₂ and AlF₃ as standards, to allow quantitative elemental analyses. The data processing was performed using Oxford Inca software. The characteristic emission lines used for the analysis were Kα for Al and F, and Mα for Sm, Eu and Gd. The morphologies of the powders were observed using secondary electrons at an accelerating voltage of 20 kV, a current of 1.1 × 10⁻¹¹ A and a working distance of 9 mm. These samples were metallized by gold sputtering for better image definition.

3. Results and discussion

The X-ray powder diffraction patterns recorded from Ln₄(Al₂O₇□)O₂ (Ln = Sm, Eu, Gd) and their new fluorinated derivatives are shown in Fig. 1. The XRD patterns show that all the samples consist of a single phase without impurities. Moreover, the fluorination induces a shift in peak position to lower angles corresponding to an increase in unit-cell sizes as the total anion content increases.

Figure 1
X-ray powder diffraction patterns recorded from materials of composition Ln₄(Al₂O₇□)O₂ (Ln = Sm, Eu, Gd) and their fluorinated derivatives.

The volumes recorded from the pure oxides and their fluorinated derivatives are graphically represented in Fig. 2. From the data in the graphic it can be seen that the fluorination leads to a significant increase in unit-cell parameters. The volume difference between the starting oxide and fluorinated oxides becomes more noticeable as the rare earth size decreases. Moreover, the cell parameters change in good agreement with the variation of the ionic radii of the rare-earth cations, with the largest cell volume observed for the Sm system and the smallest for the Gd system (Morán-Ruiz et al., 2018) [Gd³⁺ (coordination number VII): 1.00 Å; Gd³⁺ (VIII): 1.05 Å; Eu³⁺ (VII): 1.01 Å; Eu³⁺ (VIII): 1.07 Å; Sm³⁺ (VII): 1.02 Å; Sm³⁺ (VIII): 1.08 Å].

Figure 2
The volume changes between the pure oxides and their fluorinated derivatives.

Representative SEM micrographs of the powder samples (as prepared and after fluorination at 400°C) are shown in Fig. 3. As observed, no significant differences can be seen in the morphology or the average particle size of the different samples in these images. All samples are composed of agglomerated sub-micrometre particles.

Figure 3
Micrographs of Sm₄(Al₂O₆F₂)O₂, Eu₄(Al₂O₆F₂)O₂ and Gd₄(Al₂O₆F₂)O₂ phases prepared using a low-temperature fluorination route.

The chemical compositions of the obtained fluorinated oxides were analysed using SEM–EDX. The measured values of the elements were checked on different points to obtain the average composition. The atomic percentage concentrations of detected elements are listed in Table 1. For comparison, data were also collected for Eu₄(Al₂O₇□)O₂ fluorinated with half the molar equivalents of PVDF, in order to illustrate that F content can be controlled by the amount of polymer added.

Table 1
Chemical compositions (at.%) of fluorinated oxides obtained under various synthetic conditions

The use of plasma-cleaning could reduce the fluorine content near to 12.5 at.%.

Sample	Ln†	Al	F
Sm₄(Al₂O_7−xF_2x)O₂	24.0 (2)	12.2 (2)	13.4 (3)
Eu₄(Al₂O_7−xF_2x)O₂	25.0 (4)	12.2 (3)	13.1 (1)
Gd₄(Al₂O_7−xF_2x)O₂	25.6 (2)	12.6 (3)	13.6 (2)
Eu₄(Al₂O_7−xF_2x)O₂‡	23.2 (1)	12.0 (2)	6.9 (1)
Eu₄(Al₂O_7−xF_2x)O₂§	22.7 (2)	11.5 (1)	12.7 (2)
Eu₄(Al₂O_7−xF_2x)O₂¶	23.0 (1)	11.5 (1)	12.3 (1)
Theoretical Ln₄(Al₂O₆F₂)O₂	25	12.5	12.5

†Ln = Sm, Eu, Gd.
‡Fluorination reaction using ½ PVDF [equivalent to 1 F (x = 0.5) incorporation].
§Fluorination reaction using poly(tetrafluoroethylene) (PTFE).
¶Fluorination reaction using ½ PTFE.

These results indicate that the substitution of two fluorine atoms for one oxygen is satisfactorily achieved to obtain new Ln₄Al₂O₈F₂ (Ln = Sm, Eu, Gd) compositions. Examination of the fluorination with higher levels of PVDF led to no further increase in cell volume, illustrating the maximum F content had been reached. From these results it can be concluded that these cuspidine phases permit a maximum of two fluorine atoms per formula.

The samples were heated in a thermogravimetric analyzer in air at 900°C. The thermograms of all oxyfluorides are shown in Fig. 4. A decrease in mass with increasing temperature occurs between 550 and 900°C, which is associated with the loss of fluorine content due to the reaction with moisture in the air, leading to loss of HF and replacement by oxygen to reform the simple oxide system.

Figure 4
Thermogravimetric analysis of new Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Eu, Gd) phases.

For all compositions, a gravimetric mass loss of ∼3% is observed. From these results the (O/F)_z relation is calculated (Table 2).

Table 2
Fluorine content loss calculated from the gravimetric mass loss (550–900°C)

Sample	x
Sm₄(Al₂O_7−xF_2x)O₂	0.52
Eu₄(Al₂O_7−xF_2x)O₂	0.93
Gd₄(Al₂O_7−xF_2x)O₂	0.72

From the TGA data it can be concluded that the mass loss is not complete due to the low kinetic decomposition of these compounds. Preliminary studies show that the stabilization of the mass requires a long heating time (∼6 h) at 1000°C (see supporting information, Fig. S1). In order to obtain the total fluorine content remaining in each sample after treatment at 900°C, the residues were analyzed by EDX. The atomic percentage concentrations of detected elements are summarized in Table 3. The obtained data coincide with the calculated fluorine content loss.

Table 3
Chemical compositions (at.%) of the TGA residues of fluorinated oxides

Residue	Ln† (at.%)	Al (at.%)	F (at.%)
Sm₄(Al₂O_7−xF_2x)O₂	24.8 (3)	12.6 (3)	6.6 (3)
Eu₄(Al₂O_7−xF_2x)O₂	26.9 (1)	12.7 (1)	1.0 (1)
Gd₄(Al₂O_7−xF_2x)O₂	27.4 (3)	11.5 (3)	2.8 (6)

†Ln = Sm, Eu, Gd.

The success of the fluorination of rare-earth aluminates is also confirmed by XPS. A clear peak is observed in the analysed areas of the fluorinated oxides using a wide scan up to 1380 eV, attributable to an F 1s photoelectron (Fig. 5).

Figure 5
As an example, XPS survey spectra of the surface composition Sm₄(Al₂O₇□)O₂ and their new fluorinated derivative.

The resultant peak BEs before and after fluorination are presented in Table 4. In particular, we observe that fluorine incorporation induces an increase of the BEs of Al 2p and Ln 4d due to fluorine having a higher electronegativity than oxide.

Table 4
XPS analysis results of detected elements for the surface of the obtained Ln₄(Al₂O_7−xF_2x)O₂ compositions

Sample	Ln 4d† (BE, eV)	Al 2p (BE, eV)	F 1s (BE, eV)
Sm₄(Al₂O₇)O₂	131.7	73.1	–
Sm₄(Al₂O_7−xF_2x)O₂	133.1	74.3	685.0
Eu₄(Al₂O₇)O₂	135.5	73.1	–
Eu₄(Al₂O_7−xF_2x)O₂	137.0	74.3	686.5
Gd₄(Al₂O₇)O₂	141.9	73.1	–
Gd₄(Al₂O_7−xF_2x)O₂	142.8	74.3	685.3

†Ln = Sm, Eu, Gd.

This indicates greater electron transfer to fluorine, causing a decrease in the electron density at the cation and resulting in higher binding energy of the electrons from the core level of the cation (Dae-Min et al., 2011 ). These peak-position shifts are observed in the high-resolution spectra of the Al 2p and Ln 4d spectral regions (Fig. 6).

Figure 6
As an example, Al 2p spectral regions of the surface of Sm₄(Al₂O₇□)O₂ and their new fluorinated derivative showing a shift to higher binding energy upon fluorination.

The ²⁷Al NMR spectra of the fluorinated samples and Ln₄(Al₂O₇)O₂ (Ln = Sm, Eu, Gd) are provided as supporting information (Fig. S2). It seems that the shape of the Ln₄(Al₂O₆F₂)O₂ spectra changes compared with the Ln₄(Al₂O₇)O₂ spectra, which could be due to a modification of the coordination environment of Al³⁺ in the fluorinated derivatives. However, the obtained ²⁷Al NMR data are not conclusive due to the paramagnetism of Sm, Eu and Gd rare-earth metals.

Full structural refinements of XRD data for Sm₄Al₂O_9−xF_2x and Eu₄Al₂O_9−xF_2x were carried out in the space group P2₁/c by using the Sm₄(Al₂O₇)O₂ and Eu₄(Al₂O₇)O₂ structures as starting models, respectively. Refined cell and positional parameters, obtained bond distances and angles, and the bond valences are summarized in Tables S1–S11. The Rietveld fittings of the X-ray data are displayed in Fig. 7.

Figure 7
Rietveld refinement for new Sm₄(Al₂O₆F₂)O₂ and Eu₄(Al₂O₆F₂)O₂ cuspidine-related materials.

After the convergence of the overall parameters, the occupation of the bridge oxygen site O(5) was replaced by F(1) (Kendrick et al., 2008 ) and an extra fluorine position, F(2) (Martín-Sedeño et al., 2006), was added in the vacant anion site between two Al₂O₇ units, in order to account for the increase in anion content, and then refined. In both refinements, bond-length constraints were applied. The quality factors of the refinements are given in Table 5. It should be noted that distinguishing O and F by either X-ray or neutron diffraction is very difficult because of the nearly identical scattering factors. Therefore, the respective positions are commonly inferred by bond valence sum (BVS) calculations from the determined bond distances. In this respect, neutron diffraction data would lead to more accurate O/F positions and hence bond distances. However, Gd, Sm and Eu all show very strong neutron absorption, which makes such studies impractical. Therefore we have used BVS calculations based on the structures determined from the X-ray diffraction data. These calculations are in agreement with the assignment of the F positions proposed, which is further supported by the Raman results (see later). In addition, the BVS values that are calculated for the F(1) and F(2) sites, assuming O is present, show a critical deficit of valence charge in the oxygen atoms. These results add further weight to the conclusion that F occupies these sites.

Table 5
The quality of refinements performed on new fluorinated oxides

Samples	Sm₄Al₂O_9−xF_2x	Eu₄Al₂O_9−xF_2x
χ²	3.7	5.7
R_Bragg	12.8	11.7
R_f	10.6	9.2
R_p	10.9	10.2
R_wp	13.6	12.8
R_exp	7.06	5.39

The introduction of fluorine leads to the conversion of isolated M₂O₇□ groups into infinite chains of distorted square-based pyramids along the a axis, as observed for La₄(Ti₂O₈)O₂.

It is interesting to compare the present results with those of Si cuspidines of the M₄(Si₂O₇)F₂ type (Achary et al., 2017 ), where the Si₂O₇ units are preserved and fluorine occupies the O(8) and O(9) sites instead of filling the anionic vacancies and substituting for bridge oxygen ions along the AlO₄ chains. The different behaviour can be attributed to the larger size of Al cations compared with Si, and its higher ability to accommodate coordination numbers greater than four.

In summary, the structures of Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Eu) are monoclinic (P2₁/c) with two sites for fluorine between the aluminate groups. Thus, as observed from Figs. 8 and 9, the aluminium coordination changes from four to five. Because of low crystallinity, the Gd₄(Al₂O_7−xF₂)O₂ diffractogram produces a poor signal, which limits its Rietveld refinement. This lower crystallinity is probably related to the fact that Gd is the smallest rare-earth metal and also the large volume change upon fluorination, which may have reduced the particle size/crystallinity. Considering Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Eu) as representative structures of the obtained Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Gd) compositions, similar results could be expected for the gadolinium sample.

Figure 8
As an example, a polyhedral view of the Eu₄(Al₂O₇□)O₂ and Eu₄(Al₂O₆F₂)O₂ phases obtained from the Rietveld refinement structural data using Atoms62 software.

Figure 9
As an example, a simplified representation of the new Eu₄(Al₂O₆F₂)O₂ phase structure obtained from the Rietveld refinement structural data using Atoms62 software.

These structural assumptions have been further discussed based on Raman results. Raman spectra are shown in Fig. 10 for samples Ln₄(Al₂O₇□)O₂ (bottom set) and Ln₄(Al₂O_7−xF_2x)O₂ (top set) (Ln = Sm, Eu, Gd). The relatively low intensity of all the spectra could be a priori attributed to the method of synthesis, where a low preparation temperature was used and thus low crystallinity was expected. The Raman spectra of the starting Ln₄(Al₂O₇□)O₂ materials are quite similar, since they are structurally akin, and are in good agreement with the bibliography (Hasdinor-Bin-Hassan, 2010 ). An evaluation of the whole spectra is beyond the scope of this work due to the complexity of the structure, so only the high-frequency region will be treated in detail. The as-prepared samples show four well defined bands between 700 and 800 cm⁻¹ that can be unambiguously ascribed to Al—O stretching modes, since these have shorter bond distances than Ln—O. In the cuspidine structure, the existence of pyroaluminate units of [Al₂O₇] type suggests that it is appropriate to separate the expected modes into internal pyrogroup modes and lattice modes, although the covalent degree of the Al—O bond is lower than that of Si—O or P—O bonds in [Si₂O₇] or [P₂O₇] groups. Moreover, since these units are disconnected within the structure, correlation effects can be dismissed.

Figure 10
Raman spectra of the pristine Ln₄(Al₂O₇□)O₂ and Ln₄(Al₂O₆F₂)O₂ samples. Bottom to top: Ln = Sm, Eu, Gd.

Following this approach, and taking into consideration the crystallographic results, the [Al₂O₇] units can be considered as consisting of two AlO₃ pyramids connected by a bridging oxygen O′ [O(5) in Tables S2 and S3] in the form O₃—Al—O′—Al—O_3. Within this model, the expected modes can be divided into vibrational modes of the AlO₃ pyramids and those of the Al—O′—Al bridge.

A regular pyramid with C3v symmetry would give two stretching modes in the region of study, one A₁ mode and one E mode, consisting mainly of the vibration of the three oxygens of the pyramid along the Al−O bonds. However, since Al is located in a 4e site with very low local symmetry (C1), the pyramids must be considered as irregular, giving three A modes. On the other hand, the Al—O′—Al bridge is expected to give two stretching modes: one symmetric mode coming mainly from the vibration of Al atoms and one antisymmetric mode involving Al and O vibrations. The energy of the former will obviously depend on the cation and is found between 520–560 cm⁻¹ in the case of [Ge₂O₇] (Saez-Puche et al., 1992 ; Hanuza et al., 2011 ) and [Ga₂O₇] (Kaminskii et al., 2014 ) and 620–700 cm⁻¹ for [Si₂O₇] (Achary et al., 2017; Lecleach & Gillet, 1990 ), [P₂O₇] and [S₂O₇] (Kazuo, 2009 ). In our case, the Al vibration was expected to be around 600 cm⁻¹ and could be tentatively ascribed to the intense band at 590 cm⁻¹. Therefore, the only mode from the bridge in the high frequency region would be the antisymmetric mode. Although some authors have considered in analogous systems that the O′ is located in an inversion centre, thus yielding a Raman forbidden or very weak antisymmetric mode (Saez-Puche et al., 1992), the approximation needs the angle of X—O′—X to be close to 180° and both X—O′ distances to be alike. These assumptions seem to be far from our case, where the X—O′—X angle is around 140°.

Since only four modes are observed in the high-frequency region of the Ln₄(Al₂O₇□)O₂ sample, the model that best fits our data is that of two irregular but similar pyramids, which would give three stretching modes, connected by an Al—O′—Al bridge whose antisymmetric mode would supply the required fourth mode.

The model of the isolated [Al₂O₇] units is not valid anymore for the fluorinated samples, where F is proposed to be located in the interstitial positions between these units as well as substituting for the O′ in the bridge. Thus, AlO₃F₂ quasi-square pyramids sharing F vertices form infinite chains along the a axis (see Fig. 10). By applying the point group C2v symmetry operations to the constituent atoms of the pyramid (two F and two O atoms in the base and one apical O_ap), five stretching modes are expected in the high frequency region, considering that all the pyramids are equivalent: three A₁ (Al + O_ap, F, O), one B₁ (Al + F) and one B₂ (Al + O). This number of modes is in good agreement with what we observe in the spectra of the fluorinated samples, where five modes are found in the 650–820 cm⁻¹ region. The agreement with the experimental observation suggests that correlation effects, if present, result in almost degenerate modes that remain unresolved because of the spectral broadening. Regarding the symmetrical mode of the Al—O′—Al bridge in the pristine samples, its position shifts from 590 to 570 cm⁻¹ upon fluorination, which would agree with the substitution of the O′ bridge by F, supporting the assumption from the structural studies that F is located in this site.

Therefore, the Raman measurements are consistent with the crystallographic model proposed for fluorinated Ln₄(Al₂O₆F₂)O₂ cuspidines.

4. Conclusions

In summary, new Ln₄(Al₂O₆F₂)O₂ (Ln = Sm, Eu, Gd) phases with a cuspidine-related structure have been synthesized using a low-temperature fluorination route, a technique that uses Ln₄(Al₂O₇)O₂ as the oxide precursor and poly(vinylidene difluoride) as the fluorination agent. The results illustrate the versatility of this fluorination route for the synthesis of new oxide–fluoride systems. The Raman measurements are consistent with the crystallographic model proposed for new fluorinated Ln₄(Al₂O₆F₂)O₂ cuspidines: the incorporation of fluorine in the Ln₄(Al₂O₇□)O₂ structure results in Al coordination changes from four to five, which allows the conversion of isolated Al₂O₇□ groups into infinite chains of distorted square-based pyramids.

Supporting information

CCDC references: 1886577; 1886578

Crystal structure: contains datablocks global, eu4al2o8f2, sm4al2o8f2. DOI: https://doi.org/10.1107/S205225251801744X/yc5017sup1.cif

Structure factors: contains datablock eu4al2o8f2. DOI: https://doi.org/10.1107/S205225251801744X/yc5017eu4al2o8f2sup2.hkl

Structure factors: contains datablock sm4al2o8f2. DOI: https://doi.org/10.1107/S205225251801744X/yc5017sm4al2o8f2sup3.hkl

Supporting tables and figures. DOI: https://doi.org/10.1107/S205225251801744X/yc5017sup4.pdf

Computing details top

For both structures, program(s) used to refine structure: FULLPROF.

(eu4al2o8f2) top

Crystal data top

Al₂F₂O₈Eu₄	V = 862.68 (16) Å³
M_r = 827.84	Z = 4
Monoclinic, P2₁/c	D_x = 6.374 Mg m⁻³
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.540600 Å
a = 7.5885 (7) Å	T = 298 K
b = 10.8399 (12) Å	white
c = 11.0776 (13) Å	Specimen preparation: Prepared at 298 K
β = 108.788 (7)°

Data collection top

Xpert diffractometer	Detector resolution: 3.2 pixels mm^-1
Radiation source: X-ray tube	Scan method: continuous
Secondary monochromator	2θ_min = 10.000°, 2θ_max = 150.000°, 2θ_step = 0.020°

Refinement top

R_p = 10.232	7001 data points
R_wp = 12.918	6 parameters
R_exp = 5.399	34 restraints
R_Bragg = 11.883

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Eu1	0.53356	0.08498	0.79792	0.00000*
Eu2	0.02522	0.07587	0.82360	0.00000*
Eu3	0.33230	0.13132	0.41464	0.00000*
Eu4	0.83669	0.13033	0.42419	0.00000*
Al1	0.19363	0.20461	0.12699	0.00000*
Al2	0.69054	0.17756	0.13506	0.00000*
O1	0.78446	0.22994	0.75901	0.00000*
O2	0.24553	0.20276	0.77268	0.00000*
O3	0.19058	0.03573	0.13622	0.00000*
O4	0.07338	0.22831	0.97636	0.00000*
F1	0.41440	0.22370	0.10700	0.00000*
O6	0.66238	0.21371	0.98081	0.00000*
O7	0.68230	0.01240	0.16030	0.00000*
O8	0.07398	−0.00508	0.37831	0.00000*
O9	0.53190	0.02012	0.39613	0.00000*
F2	0.05064	0.76062	0.35705	0.00000*	0.99000

Geometric parameters (Å, º) top

Eu1—O1	2.6093 (2)	O3—O8	3.1144 (3)
Eu1—O2	2.4682 (2)	O3—O9	3.1974 (4)
Eu1—O3ⁱ	2.3755 (2)	O3—F2^xi	3.0638 (2)
Eu1—F1ⁱⁱ	2.8914 (2)	O4—Eu2	2.3086 (2)
Eu1—O6	2.3941 (2)	O4—Eu3ⁱⁱ	2.7402 (2)
Eu1—O7ⁱ	2.1213 (1)	O4—Eu4^xiii	2.2890 (2)
Eu1—O9ⁱ	2.3405 (2)	O4—Al1^xiv	1.6439 (2)
Eu2—O1ⁱⁱⁱ	2.4077 (2)	O4—O1ⁱⁱⁱ	2.6840 (3)
Eu2—O2	2.3691 (2)	O4—O2	2.9619 (3)
Eu2—O3^iv	2.1938 (1)	O4—O3^xiv	2.6964 (2)
Eu2—O4	2.3086 (2)	O4—F1^xiv	2.5261 (3)
Eu2—O7ⁱ	2.3703 (2)	O4—O6ⁱⁱⁱ	3.1391 (3)
Eu2—O8^iv	2.2524 (2)	O4—O8ⁱⁱ	3.1915 (3)
Eu2—F2^v	2.5953 (2)	O4—F2^xv	2.3522 (2)
Eu3—Al1	3.1197 (4)	F1—Eu1^vi	2.8914 (2)
Eu3—O2^vi	2.3398 (2)	F1—Eu3^vi	2.5581 (2)
Eu3—O3	3.0994 (3)	F1—Al1	1.7713 (1)
Eu3—O4^vi	2.7402 (2)	F1—Al2	2.0781 (2)
Eu3—F1ⁱⁱ	2.5581 (2)	F1—O1^vi	2.8157 (3)
Eu3—O6^vi	2.9070 (2)	F1—O2^vi	2.6760 (2)
Eu3—O8	2.3840 (2)	F1—O3	2.7378 (2)
Eu3—O9	1.9973 (1)	F1—O4^x	2.5261 (3)
Eu3—O9ⁱ	2.5999 (2)	F1—O6^x	2.6835 (2)
Eu4—Al2	3.0761 (4)	F1—O7	2.9924 (2)
Eu4—O1^vi	2.3092 (2)	O6—Eu1	2.3941 (2)
Eu4—O4^vii	2.2890 (2)	O6—Eu3ⁱⁱ	2.9070 (2)
Eu4—O6^vi	2.3528 (2)	O6—Eu4ⁱⁱ	2.3528 (2)
Eu4—O7	3.0572 (3)	O6—Al2^xiv	1.6982 (2)
Eu4—O8^viii	2.4991 (2)	O6—O1	2.8970 (3)
Eu4—O8ⁱ	2.4766 (2)	O6—O1ⁱⁱ	2.9816 (4)
Eu4—O9	2.5319 (2)	O6—O4^viii	3.1391 (3)
Eu4—F2^ix	2.5819 (3)	O6—F1^xiv	2.6835 (2)
Al1—Eu3	3.1197 (4)	O6—O7^xiv	2.9231 (2)
Al1—O2^vi	1.8327 (2)	O6—O9ⁱⁱ	3.0963 (3)
Al1—O3	1.8341 (2)	O6—F2^xvi	2.3891 (3)
Al1—O4^x	1.6439 (2)	O7—Eu1ⁱ	2.1213 (1)
Al1—F1	1.7713 (1)	O7—Eu2ⁱ	2.3703 (2)
Al1—F2^xi	2.0117 (2)	O7—Eu4	3.0572 (3)
Al2—Eu4	3.0761 (4)	O7—Al2	1.8162 (2)
Al2—O1^vi	1.6638 (1)	O7—O1^vi	3.0086 (3)
Al2—F1	2.0781 (2)	O7—O2ⁱ	2.4554 (2)
Al2—O6^x	1.6982 (2)	O7—F1	2.9924 (2)
Al2—O7	1.8162 (2)	O7—O6^x	2.9231 (2)
Al2—F2^xii	2.1366 (2)	O7—O8^viii	3.1748 (3)
O1—Eu1	2.6093 (2)	O7—O9	3.1710 (3)
O1—Eu2^viii	2.4077 (2)	O8—Eu2^iv	2.2524 (2)
O1—Eu4ⁱⁱ	2.3092 (2)	O8—Eu3	2.3840 (2)
O1—Al2ⁱⁱ	1.6638 (1)	O8—Eu4ⁱⁱⁱ	2.4991 (2)
O1—O3ⁱ	3.0879 (3)	O8—Eu4ⁱ	2.4766 (2)
O1—O4^viii	2.6840 (3)	O8—O3	3.1144 (3)
O1—F1ⁱⁱ	2.8157 (3)	O8—O4^vi	3.1915 (3)
O1—O6	2.8970 (3)	O8—O7ⁱⁱⁱ	3.1748 (3)
O1—O6^vi	2.9816 (4)	O8—F2^xvii	2.5514 (3)
O1—O7ⁱⁱ	3.0086 (3)	O9—Eu1ⁱ	2.3405 (2)
O1—F2^ix	2.0653 (2)	O9—Eu3	1.9973 (1)
O2—Eu1	2.4682 (2)	O9—Eu3ⁱ	2.5999 (2)
O2—Eu2	2.3691 (2)	O9—Eu4	2.5319 (2)
O2—Eu3ⁱⁱ	2.3398 (2)	O9—O3	3.1974 (4)
O2—Al1ⁱⁱ	1.8327 (2)	O9—O6^vi	3.0963 (3)
O2—O3ⁱⁱ	3.1763 (3)	O9—O7	3.1710 (3)
O2—O4	2.9619 (3)	O9—O9ⁱ	2.5374 (3)
O2—F1ⁱⁱ	2.6760 (2)	F2—Eu2^v	2.5953 (2)
O2—O7ⁱ	2.4554 (2)	F2—Eu4^ix	2.5819 (3)
O2—F2^v	2.2789 (2)	F2—Al1^xviii	2.0117 (2)
O3—Eu1ⁱ	2.3755 (2)	F2—Al2^xix	2.1366 (2)
O3—Eu2^iv	2.1938 (1)	F2—O1^ix	2.0653 (2)
O3—Eu3	3.0994 (3)	F2—O2^v	2.2789 (2)
O3—Al1	1.8341 (2)	F2—O3^xviii	3.0638 (2)
O3—O1ⁱ	3.0879 (3)	F2—O4^xx	2.3522 (2)
O3—O2^vi	3.1763 (3)	F2—O6^xxi	2.3891 (3)
O3—O4^x	2.6964 (2)	F2—O8^xxii	2.5514 (3)
O3—F1	2.7378 (2)

O1—Eu1—O2	109.660 (15)	Eu2—O4—O1ⁱⁱⁱ	57.072 (9)
O1—Eu1—O3ⁱ	76.392 (10)	Eu2—O4—O2	51.626 (8)
O1—Eu1—F1ⁱⁱ	61.325 (9)	Eu2—O4—O3^xiv	82.421 (14)
O1—Eu1—O6	70.610 (10)	Eu2—O4—F1^xiv	107.271 (16)
O1—Eu1—O7ⁱ	172.523 (17)	Eu2—O4—O6ⁱⁱⁱ	92.975 (12)
O1—Eu1—O9ⁱ	95.264 (12)	Eu2—O4—O8ⁱⁱ	116.15 (2)
O2—Eu1—O3ⁱ	168.629 (19)	Eu2—O4—F2^xv	132.284 (19)
O2—Eu1—F1ⁱⁱ	59.282 (8)	Eu3ⁱⁱ—O4—Eu4^xiii	97.623 (13)
O2—Eu1—O6	84.243 (13)	Eu3ⁱⁱ—O4—Al1^xiv	97.576 (14)
O2—Eu1—O7ⁱ	64.167 (9)	Eu3ⁱⁱ—O4—O1ⁱⁱⁱ	102.516 (15)
O2—Eu1—O9ⁱ	103.268 (12)	Eu3ⁱⁱ—O4—O2	48.259 (7)
O3ⁱ—Eu1—F1ⁱⁱ	131.058 (17)	Eu3ⁱⁱ—O4—O3^xiv	118.845 (14)
O3ⁱ—Eu1—O6	88.963 (11)	Eu3ⁱⁱ—O4—F1^xiv	57.951 (9)
O3ⁱ—Eu1—O7ⁱ	108.960 (16)	Eu3ⁱⁱ—O4—O6ⁱⁱⁱ	145.874 (18)
O3ⁱ—Eu1—O9ⁱ	85.372 (14)	Eu3ⁱⁱ—O4—O8ⁱⁱ	46.630 (7)
F1ⁱⁱ—Eu1—O6	98.465 (18)	Eu3ⁱⁱ—O4—F2^xv	127.829 (16)
F1ⁱⁱ—Eu1—O7ⁱ	115.783 (14)	Eu4^xiii—O4—Al1^xiv	119.658 (17)
F1ⁱⁱ—Eu1—O9ⁱ	75.727 (12)	Eu4^xiii—O4—O1ⁱⁱⁱ	54.638 (9)
O6—Eu1—O7ⁱ	103.824 (13)	Eu4^xiii—O4—O2	111.901 (13)
O6—Eu1—O9ⁱ	165.69 (2)	Eu4^xiii—O4—O3^xiv	138.601 (17)
O7ⁱ—Eu1—O9ⁱ	90.446 (13)	Eu4^xiii—O4—F1^xiv	137.19 (2)
O1ⁱⁱⁱ—Eu2—O2	93.017 (13)	Eu4^xiii—O4—O6ⁱⁱⁱ	48.311 (7)
O1ⁱⁱⁱ—Eu2—O3^iv	84.159 (12)	Eu4^xiii—O4—O8ⁱⁱ	51.077 (8)
O1ⁱⁱⁱ—Eu2—O4	69.339 (11)	Eu4^xiii—O4—F2^xv	67.586 (10)
O1ⁱⁱⁱ—Eu2—O7ⁱ	154.807 (18)	Al1^xiv—O4—O1ⁱⁱⁱ	159.66 (3)
O1ⁱⁱⁱ—Eu2—O8^iv	87.835 (11)	Al1^xiv—O4—O2	121.45 (2)
O1ⁱⁱⁱ—Eu2—F2^v	48.585 (7)	Al1^xiv—O4—O6ⁱⁱⁱ	101.871 (19)
O2—Eu2—O3^iv	176.953 (16)	Al1^xiv—O4—O8ⁱⁱ	115.545 (18)
O2—Eu2—O4	78.562 (11)	Al1^xiv—O4—F2^xv	57.210 (10)
O2—Eu2—O7ⁱ	62.407 (9)	O1ⁱⁱⁱ—O4—O2	75.553 (12)
O2—Eu2—O8^iv	89.833 (12)	O1ⁱⁱⁱ—O4—O3^xiv	126.56 (2)
O2—Eu2—F2^v	54.421 (8)	O1ⁱⁱⁱ—O4—F1^xiv	154.71 (3)
O3^iv—Eu2—O4	101.436 (13)	O1ⁱⁱⁱ—O4—O6ⁱⁱⁱ	59.053 (10)
O3^iv—Eu2—O7ⁱ	120.277 (17)	O1ⁱⁱⁱ—O4—O8ⁱⁱ	77.220 (11)
O3^iv—Eu2—O8^iv	88.916 (14)	O1ⁱⁱⁱ—O4—F2^xv	106.57 (2)
O3^iv—Eu2—F2^v	122.571 (15)	O2—O4—O3^xiv	107.146 (16)
O4—Eu2—O7ⁱ	108.087 (12)	O2—O4—F1^xiv	79.209 (14)
O4—Eu2—O8^iv	153.52 (2)	O2—O4—O6ⁱⁱⁱ	133.746 (18)
O4—Eu2—F2^v	91.135 (16)	O2—O4—O8ⁱⁱ	77.251 (11)
O7ⁱ—Eu2—O8^iv	86.710 (14)	O2—O4—F2^xv	176.09 (2)
O7ⁱ—Eu2—F2^v	107.667 (13)	O3^xiv—O4—F1^xiv	63.133 (9)
O8^iv—Eu2—F2^v	63.045 (11)	O3^xiv—O4—O6ⁱⁱⁱ	94.007 (13)
Al1—Eu3—O4^vi	94.609 (15)	O3^xiv—O4—O8ⁱⁱ	156.21 (2)
Al1—Eu3—F1ⁱⁱ	127.30 (2)	O3^xiv—O4—F2^xv	74.377 (10)
Al1—Eu3—O6^vi	95.174 (16)	F1^xiv—O4—O6ⁱⁱⁱ	146.07 (2)
Al1—Eu3—O8	89.829 (12)	F1^xiv—O4—O8ⁱⁱ	95.744 (13)
Al1—Eu3—O9	93.802 (14)	F1^xiv—O4—F2^xv	98.534 (14)
Al1—Eu3—O9ⁱ	154.16 (2)	O6ⁱⁱⁱ—O4—O8ⁱⁱ	99.385 (12)
O2^vi—Eu3—O3	69.868 (11)	O6ⁱⁱⁱ—O4—F2^xv	49.048 (9)
O2^vi—Eu3—O4^vi	70.832 (10)	O8ⁱⁱ—O4—F2^xv	99.893 (13)
O2^vi—Eu3—F1ⁱⁱ	91.601 (16)	Eu1^vi—F1—Eu3^vi	95.943 (17)
O2^vi—Eu3—O6^vi	76.018 (12)	Eu1^vi—F1—Al1	94.469 (13)
O2^vi—Eu3—O8	108.981 (14)	Eu1^vi—F1—Al2	90.028 (11)
O2^vi—Eu3—O9	116.967 (15)	Eu1^vi—F1—O1^vi	54.395 (8)
O2^vi—Eu3—O9ⁱ	168.50 (2)	Eu1^vi—F1—O2^vi	52.459 (8)
O3—Eu3—O4^vi	112.772 (15)	Eu1^vi—F1—O3	120.473 (16)
O3—Eu3—F1ⁱⁱ	161.39 (2)	Eu1^vi—F1—O4^x	115.227 (17)
O3—Eu3—O6^vi	116.025 (16)	Eu1^vi—F1—O6^x	107.662 (14)
O3—Eu3—O8	67.772 (11)	Eu1^vi—F1—O7	111.848 (16)
O3—Eu3—O9	74.195 (13)	Eu3^vi—F1—Al1	100.924 (13)
O3—Eu3—O9ⁱ	120.77 (2)	Eu3^vi—F1—Al2	103.639 (14)
O4^vi—Eu3—F1ⁱⁱ	56.827 (8)	Eu3^vi—F1—O1^vi	108.479 (18)
O4^vi—Eu3—O6^vi	104.184 (14)	Eu3^vi—F1—O2^vi	110.265 (18)
O4^vi—Eu3—O8	76.696 (11)	Eu3^vi—F1—O3	124.181 (15)
O4^vi—Eu3—O9	171.554 (17)	Eu3^vi—F1—O4^x	65.222 (9)
O4^vi—Eu3—O9ⁱ	106.219 (13)	Eu3^vi—F1—O6^x	67.317 (9)
F1ⁱⁱ—Eu3—O6^vi	58.400 (8)	Eu3^vi—F1—O7	127.037 (16)
F1ⁱⁱ—Eu3—O8	119.219 (15)	Al1—F1—Al2	154.42 (2)
F1ⁱⁱ—Eu3—O9	117.840 (14)	Al1—F1—O1^vi	138.36 (2)
F1ⁱⁱ—Eu3—O9ⁱ	77.838 (12)	Al1—F1—O6^x	155.58 (2)
O6^vi—Eu3—O8	174.815 (18)	Al1—F1—O7	119.717 (16)
O6^vi—Eu3—O9	75.777 (11)	Al2—F1—O2^vi	130.668 (16)
O6^vi—Eu3—O9ⁱ	94.357 (12)	Al2—F1—O3	115.930 (15)
O8—Eu3—O9	102.581 (14)	Al2—F1—O4^x	152.63 (2)
O8—Eu3—O9ⁱ	80.520 (12)	O1^vi—F1—O2^vi	98.182 (14)
O9—Eu3—O9ⁱ	65.477 (10)	O1^vi—F1—O3	126.822 (16)
Al2—Eu4—O4^vii	98.159 (17)	O1^vi—F1—O4^x	168.36 (3)
Al2—Eu4—O6^vi	96.480 (16)	O1^vi—F1—O6^x	65.613 (11)
Al2—Eu4—O8^viii	85.859 (12)	O1^vi—F1—O7	62.308 (9)
Al2—Eu4—O8ⁱ	156.26 (3)	O2^vi—F1—O3	71.836 (10)
Al2—Eu4—O9	86.672 (12)	O2^vi—F1—O4^x	76.027 (13)
Al2—Eu4—F2^ix	143.17 (3)	O2^vi—F1—O6^x	160.11 (2)
O1^vi—Eu4—O4^vii	71.423 (11)	O2^vi—F1—O7	122.524 (14)
O1^vi—Eu4—O6^vi	76.831 (11)	O3—F1—O4^x	61.470 (9)
O1^vi—Eu4—O7	66.513 (10)	O3—F1—O6^x	126.682 (15)
O1^vi—Eu4—O8^viii	100.090 (13)	O3—F1—O7	79.334 (11)
O1^vi—Eu4—O8ⁱ	171.05 (2)	O4^x—F1—O6^x	117.595 (17)
O1^vi—Eu4—O9	107.179 (12)	O4^x—F1—O7	129.323 (18)
O1^vi—Eu4—F2^ix	111.34 (2)	O6^x—F1—O7	61.711 (8)
O4^vii—Eu4—O6^vi	85.093 (11)	Eu1—O6—Eu3ⁱⁱ	92.270 (12)
O4^vii—Eu4—O7	123.315 (17)	Eu1—O6—Eu4ⁱⁱ	107.734 (14)
O4^vii—Eu4—O8^viii	83.478 (12)	Eu1—O6—Al2^xiv	127.00 (2)
O4^vii—Eu4—O8ⁱ	100.057 (12)	Eu1—O6—O1	58.171 (9)
O4^vii—Eu4—O9	163.413 (18)	Eu1—O6—O1ⁱⁱ	154.20 (3)
O4^vii—Eu4—F2^ix	57.372 (9)	Eu1—O6—O4^viii	98.804 (14)
O6^vi—Eu4—O7	118.696 (16)	Eu1—O6—F1^xiv	107.496 (16)
O6^vi—Eu4—O8^viii	168.549 (16)	Eu1—O6—O7^xiv	93.329 (16)
O6^vi—Eu4—O8ⁱ	100.124 (13)	Eu1—O6—O9ⁱⁱ	106.450 (17)
O6^vi—Eu4—O9	78.580 (11)	Eu1—O6—F2^xvi	141.74 (2)
O6^vi—Eu4—F2^ix	57.688 (9)	Eu3ⁱⁱ—O6—Eu4ⁱⁱ	91.736 (13)
O7—Eu4—O8^viii	68.852 (11)	Eu3ⁱⁱ—O6—Al2^xiv	101.891 (15)
O7—Eu4—O8ⁱ	121.81 (2)	Eu3ⁱⁱ—O6—O1	103.650 (13)
O7—Eu4—O9	68.389 (11)	Eu3ⁱⁱ—O6—O1ⁱⁱ	95.618 (16)
O7—Eu4—F2^ix	176.37 (3)	Eu3ⁱⁱ—O6—O4^viii	138.303 (19)
O8^viii—Eu4—O8ⁱ	81.230 (12)	Eu3ⁱⁱ—O6—F1^xiv	54.282 (8)
O8^viii—Eu4—O9	112.793 (16)	Eu3ⁱⁱ—O6—O7^xiv	117.033 (15)
O8^viii—Eu4—F2^ix	114.667 (14)	Eu3ⁱⁱ—O6—F2^xvi	124.70 (2)
O8ⁱ—Eu4—O9	80.162 (13)	Eu4ⁱⁱ—O6—Al2^xiv	122.323 (16)
O8ⁱ—Eu4—F2^ix	60.536 (10)	Eu4ⁱⁱ—O6—O1	50.909 (8)
O9—Eu4—F2^ix	110.153 (15)	Eu4ⁱⁱ—O6—O1ⁱⁱ	96.554 (16)
Eu3—Al1—O2^vi	48.233 (10)	Eu4ⁱⁱ—O6—O4^viii	46.595 (7)
Eu3—Al1—O3	72.244 (14)	Eu4ⁱⁱ—O6—F1^xiv	131.196 (16)
Eu3—Al1—O4^x	166.16 (3)	Eu4ⁱⁱ—O6—O7^xiv	143.843 (17)
Eu3—Al1—F1	97.815 (17)	Eu4ⁱⁱ—O6—O9ⁱⁱ	53.275 (8)
Eu3—Al1—F2^xi	90.248 (15)	Eu4ⁱⁱ—O6—F2^xvi	65.976 (10)
O2^vi—Al1—O3	120.051 (18)	Al2^xiv—O6—O1	153.70 (3)
O2^vi—Al1—O4^x	134.42 (2)	Al2^xiv—O6—O4^viii	102.930 (16)
O2^vi—Al1—F1	95.879 (13)	Al2^xiv—O6—F1^xiv	50.748 (10)
O2^vi—Al1—F2^xi	72.543 (11)	Al2^xiv—O6—O9ⁱⁱ	116.373 (18)
O3—Al1—O4^x	101.522 (15)	Al2^xiv—O6—F2^xvi	60.251 (10)
O3—Al1—F1	98.801 (13)	O1—O6—O1ⁱⁱ	141.85 (3)
O3—Al1—F2^xi	105.534 (14)	O1—O6—O4^viii	52.618 (9)
O4^x—Al1—F1	95.337 (16)	O1—O6—F1^xiv	155.34 (2)
O4^x—Al1—F2^xi	79.401 (12)	O1—O6—O7^xiv	131.425 (19)
F1—Al1—F2^xi	155.66 (2)	O1—O6—O9ⁱⁱ	81.075 (10)
Eu4—Al2—O1^vi	47.629 (10)	O1—O6—F2^xvi	99.303 (19)
Eu4—Al2—F1	101.762 (18)	O1ⁱⁱ—O6—O4^viii	91.511 (14)
Eu4—Al2—O6^x	166.51 (3)	O1ⁱⁱ—O6—F1^xiv	59.328 (10)
Eu4—Al2—O7	72.205 (14)	O1ⁱⁱ—O6—O7^xiv	61.255 (10)
Eu4—Al2—F2^xii	90.523 (14)	O1ⁱⁱ—O6—O9ⁱⁱ	94.866 (15)
O1^vi—Al2—F1	96.990 (15)	O4^viii—O6—F1^xiv	150.82 (2)
O1^vi—Al2—O6^x	124.96 (2)	O4^viii—O6—O7^xiv	102.377 (12)
O1^vi—Al2—O7	119.594 (18)	O4^viii—O6—O9ⁱⁱ	99.826 (13)
O1^vi—Al2—F2^xii	64.437 (9)	O4^viii—O6—F2^xvi	48.038 (9)
F1—Al2—O6^x	89.995 (13)	F1^xiv—O6—O7^xiv	64.349 (8)
F1—Al2—O7	100.208 (13)	F1^xiv—O6—O9ⁱⁱ	84.879 (11)
F1—Al2—F2^xii	140.72 (2)	F1^xiv—O6—F2^xvi	102.834 (15)
O6^x—Al2—O7	112.517 (16)	O7^xiv—O6—O9ⁱⁱ	147.48 (2)
O6^x—Al2—F2^xii	76.116 (12)	O7^xiv—O6—F2^xvi	79.198 (11)
O7—Al2—F2^xii	119.069 (15)	O9ⁱⁱ—O6—F2^xvi	98.891 (14)
Eu1—O1—Eu2^viii	93.291 (13)	Eu1ⁱ—O7—Eu2ⁱ	123.561 (17)
Eu1—O1—Eu4ⁱⁱ	102.255 (13)	Eu1ⁱ—O7—Eu4	94.847 (13)
Eu1—O1—Al2ⁱⁱ	110.967 (14)	Eu1ⁱ—O7—Al2	126.256 (16)
Eu1—O1—O3ⁱ	48.391 (8)	Eu1ⁱ—O7—O1^vi	120.620 (17)
Eu1—O1—O4^viii	106.053 (15)	Eu1ⁱ—O7—O2ⁱ	64.790 (9)
Eu1—O1—F1ⁱⁱ	64.280 (9)	Eu1ⁱ—O7—F1	84.300 (13)
Eu1—O1—O6	51.219 (8)	Eu1ⁱ—O7—O6^x	130.202 (15)
Eu1—O1—O6^vi	107.084 (15)	Eu1ⁱ—O7—O8^viii	113.818 (19)
Eu1—O1—O7ⁱⁱ	120.184 (17)	Eu1ⁱ—O7—O9	47.567 (8)
Eu1—O1—F2^ix	138.876 (16)	Eu2ⁱ—O7—Eu4	92.044 (12)
Eu2^viii—O1—Eu4ⁱⁱ	107.418 (14)	Eu2ⁱ—O7—Al2	109.371 (15)
Eu2^viii—O1—Al2ⁱⁱ	138.213 (18)	Eu2ⁱ—O7—O1^vi	102.825 (15)
Eu2^viii—O1—O4^viii	53.589 (9)	Eu2ⁱ—O7—O2ⁱ	58.772 (8)
Eu2^viii—O1—F1ⁱⁱ	144.76 (2)	Eu2ⁱ—O7—F1	152.128 (17)
Eu2^viii—O1—O6	97.190 (12)	Eu2ⁱ—O7—O6^x	101.220 (13)
Eu2^viii—O1—O6^vi	113.747 (17)	Eu2ⁱ—O7—O8^viii	45.098 (9)
Eu2^viii—O1—O7ⁱⁱ	146.51 (2)	Eu2ⁱ—O7—O9	121.696 (16)
Eu2^viii—O1—F2^ix	70.456 (9)	Eu4—O7—Al2	73.347 (15)
Eu4ⁱⁱ—O1—Al2ⁱⁱ	100.208 (18)	Eu4—O7—O2ⁱ	97.389 (14)
Eu4ⁱⁱ—O1—O3ⁱ	109.866 (19)	Eu4—O7—F1	83.995 (13)
Eu4ⁱⁱ—O1—O4^viii	53.938 (9)	Eu4—O7—O6^x	104.963 (19)
Eu4ⁱⁱ—O1—F1ⁱⁱ	103.911 (17)	Eu4—O7—O8^viii	47.236 (9)
Eu4ⁱⁱ—O1—O6	52.260 (8)	Eu4—O7—O9	47.929 (9)
Eu4ⁱⁱ—O1—O6^vi	126.98 (2)	Al2—O7—O2ⁱ	165.35 (3)
Eu4ⁱⁱ—O1—O7ⁱⁱ	68.743 (11)	Al2—O7—O8^viii	96.073 (15)
Eu4ⁱⁱ—O1—F2^ix	118.489 (17)	Al2—O7—O9	98.059 (15)
Al2ⁱⁱ—O1—O3ⁱ	146.13 (2)	O1^vi—O7—O2ⁱ	139.96 (2)
Al2ⁱⁱ—O1—O4^viii	138.88 (3)	O1^vi—O7—F1	55.964 (9)
Al2ⁱⁱ—O1—F1ⁱⁱ	47.100 (9)	O1^vi—O7—O6^x	60.331 (10)
Al2ⁱⁱ—O1—O6	124.58 (2)	O1^vi—O7—O8^viii	73.170 (11)
Al2ⁱⁱ—O1—F2^ix	68.949 (9)	O1^vi—O7—O9	78.173 (10)
O3ⁱ—O1—O4^viii	73.930 (11)	O2ⁱ—O7—F1	149.08 (2)
O3ⁱ—O1—F1ⁱⁱ	108.655 (14)	O2ⁱ—O7—O6^x	150.74 (2)
O3ⁱ—O1—O6	67.805 (10)	O2ⁱ—O7—O8^viii	69.527 (10)
O3ⁱ—O1—O6^vi	122.724 (17)	O2ⁱ—O7—O9	83.129 (11)
O3ⁱ—O1—O7ⁱⁱ	168.48 (2)	F1—O7—O6^x	53.940 (8)
O3ⁱ—O1—F2^ix	107.702 (14)	F1—O7—O8^viii	127.296 (18)
O4^viii—O1—F1ⁱⁱ	155.07 (3)	F1—O7—O9	74.956 (10)
O4^viii—O1—O6	68.329 (11)	O6^x—O7—O8^viii	113.122 (17)
O4^viii—O1—O6^vi	145.15 (3)	O6^x—O7—O9	125.959 (19)
O4^viii—O1—O7ⁱⁱ	111.874 (16)	O8^viii—O7—O9	82.650 (12)
O4^viii—O1—F2^ix	94.308 (18)	Eu2^iv—O8—Eu3	111.874 (15)
F1ⁱⁱ—O1—O6	89.329 (16)	Eu2^iv—O8—Eu4ⁱⁱⁱ	111.701 (14)
F1ⁱⁱ—O1—O6^vi	55.058 (10)	Eu2^iv—O8—Eu4ⁱ	126.83 (2)
F1ⁱⁱ—O1—O7ⁱⁱ	61.728 (9)	Eu2^iv—O8—O4^vi	128.426 (18)
F1ⁱⁱ—O1—F2^ix	107.842 (17)	Eu2^iv—O8—O7ⁱⁱⁱ	48.193 (10)
O6—O1—O6^vi	144.22 (3)	Eu2^iv—O8—F2^xvii	65.056 (11)
O6—O1—O7ⁱⁱ	104.435 (14)	Eu3—O8—Eu4ⁱⁱⁱ	102.030 (14)
O6—O1—F2^ix	162.62 (2)	Eu3—O8—Eu4ⁱ	102.394 (12)
O6^vi—O1—O7ⁱⁱ	58.415 (10)	Eu3—O8—O3	67.108 (11)
O6^vi—O1—F2^ix	52.791 (10)	Eu3—O8—O4^vi	56.674 (8)
O7ⁱⁱ—O1—F2^ix	82.219 (11)	Eu3—O8—O7ⁱⁱⁱ	127.50 (2)
Eu1—O2—Eu2	109.863 (15)	Eu3—O8—F2^xvii	131.444 (19)
Eu1—O2—Eu3ⁱⁱ	105.917 (13)	Eu4ⁱⁱⁱ—O8—Eu4ⁱ	98.770 (12)
Eu1—O2—Al1ⁱⁱ	108.329 (14)	Eu4ⁱⁱⁱ—O8—O3	120.983 (17)
Eu1—O2—O3ⁱⁱ	119.426 (16)	Eu4ⁱⁱⁱ—O8—O4^vi	45.446 (7)
Eu1—O2—O4	123.630 (15)	Eu4ⁱⁱⁱ—O8—O7ⁱⁱⁱ	63.911 (10)
Eu1—O2—F1ⁱⁱ	68.259 (9)	Eu4ⁱⁱⁱ—O8—F2^xvii	124.775 (18)
Eu1—O2—O7ⁱ	51.042 (8)	Eu4ⁱ—O8—O3	139.97 (2)
Eu1—O2—F2^v	144.99 (2)	Eu4ⁱ—O8—O4^vi	104.161 (17)
Eu2—O2—Eu3ⁱⁱ	110.713 (14)	Eu4ⁱ—O8—O7ⁱⁱⁱ	128.87 (2)
Eu2—O2—Al1ⁱⁱ	124.042 (15)	Eu4ⁱ—O8—F2^xvii	61.775 (10)
Eu2—O2—O3ⁱⁱ	129.564 (17)	O3—O8—O4^vi	101.035 (14)
Eu2—O2—O4	49.813 (8)	O3—O8—O7ⁱⁱⁱ	78.023 (12)
Eu2—O2—F1ⁱⁱ	150.087 (16)	O3—O8—F2^xvii	95.307 (13)
Eu2—O2—O7ⁱ	58.821 (8)	O4^vi—O8—O7ⁱⁱⁱ	95.688 (14)
Eu2—O2—F2^v	67.854 (9)	O4^vi—O8—F2^xvii	163.65 (3)
Eu3ⁱⁱ—O2—Al1ⁱⁱ	96.019 (17)	O7ⁱⁱⁱ—O8—F2^xvii	88.230 (13)
Eu3ⁱⁱ—O2—O3ⁱⁱ	66.373 (11)	Eu1ⁱ—O9—Eu3	116.386 (14)
Eu3ⁱⁱ—O2—O4	60.909 (8)	Eu1ⁱ—O9—Eu3ⁱ	110.18 (2)
Eu3ⁱⁱ—O2—F1ⁱⁱ	97.973 (15)	Eu1ⁱ—O9—Eu4	104.935 (14)
Eu3ⁱⁱ—O2—O7ⁱ	122.67 (2)	Eu1ⁱ—O9—O3	47.775 (9)
Eu3ⁱⁱ—O2—F2^v	107.268 (17)	Eu1ⁱ—O9—O6^vi	133.191 (18)
Al1ⁱⁱ—O2—O4	126.67 (2)	Eu1ⁱ—O9—O9ⁱ	134.69 (2)
Al1ⁱⁱ—O2—O7ⁱ	138.630 (19)	Eu3—O9—Eu3ⁱ	114.523 (14)
Al1ⁱⁱ—O2—F2^v	57.360 (9)	Eu3—O9—Eu4	113.304 (16)
O3ⁱⁱ—O2—O4	104.867 (14)	Eu3—O9—O3	68.860 (12)
O3ⁱⁱ—O2—F1ⁱⁱ	54.984 (8)	Eu3—O9—O6^vi	65.518 (9)
O3ⁱⁱ—O2—O7ⁱ	166.89 (2)	Eu3—O9—O7	125.914 (17)
O3ⁱⁱ—O2—F2^v	65.970 (10)	Eu3—O9—O9ⁱ	68.784 (10)
O4—O2—F1ⁱⁱ	157.03 (2)	Eu3ⁱ—O9—Eu4	95.149 (11)
O4—O2—O7ⁱ	88.202 (11)	Eu3ⁱ—O9—O3	139.04 (2)
O4—O2—F2^v	82.920 (15)	Eu3ⁱ—O9—O6^vi	109.820 (18)
F1ⁱⁱ—O2—O7ⁱ	112.389 (14)	Eu3ⁱ—O9—O7	119.55 (2)
F1ⁱⁱ—O2—F2^v	96.226 (14)	Eu3ⁱ—O9—O9ⁱ	45.738 (8)
O7ⁱ—O2—F2^v	115.770 (15)	Eu4—O9—O3	121.91 (2)
Eu1ⁱ—O3—Eu2^iv	105.992 (15)	Eu4—O9—O6^vi	48.145 (8)
Eu1ⁱ—O3—Eu3	83.656 (11)	Eu4—O9—O7	63.682 (10)
Eu1ⁱ—O3—Al1	122.768 (17)	Eu4—O9—O9ⁱ	113.789 (14)
Eu1ⁱ—O3—O1ⁱ	55.216 (8)	O3—O9—O6^vi	108.105 (16)
Eu1ⁱ—O3—O2^vi	112.198 (16)	O3—O9—O7	70.223 (11)
Eu1ⁱ—O3—O4^x	134.412 (17)	O3—O9—O9ⁱ	119.34 (2)
Eu1ⁱ—O3—F1	85.835 (13)	O6^vi—O9—O7	96.279 (13)
Eu1ⁱ—O3—O8	97.118 (13)	O6^vi—O9—O9ⁱ	91.217 (13)
Eu1ⁱ—O3—O9	46.853 (9)	O7—O9—O9ⁱ	165.26 (2)
Eu1ⁱ—O3—F2^xi	154.840 (18)	Eu2^v—F2—Eu4^ix	109.59 (2)
Eu2^iv—O3—Eu3	91.427 (13)	Eu2^v—F2—Al1^xviii	106.981 (13)
Eu2^iv—O3—Al1	125.829 (17)	Eu2^v—F2—Al2^xix	106.979 (13)
Eu2^iv—O3—O1ⁱ	50.868 (8)	Eu2^v—F2—O1^ix	60.959 (8)
Eu2^iv—O3—O2^vi	112.814 (17)	Eu2^v—F2—O2^v	57.725 (8)
Eu2^iv—O3—O4^x	116.763 (15)	Eu2^v—F2—O3^xviii	125.189 (16)
Eu2^iv—O3—F1	165.115 (17)	Eu2^v—F2—O4^xx	131.393 (19)
Eu2^iv—O3—O8	46.312 (8)	Eu2^v—F2—O6^xxi	130.329 (19)
Eu2^iv—O3—O9	103.253 (17)	Eu2^v—F2—O8^xxii	51.899 (9)
Eu2^iv—O3—F2^xi	86.730 (14)	Eu4^ix—F2—Al1^xviii	95.259 (13)
Eu3—O3—Al1	73.454 (15)	Eu4^ix—F2—Al2^xix	97.607 (12)
Eu3—O3—O1ⁱ	88.748 (13)	Eu4^ix—F2—O1^ix	118.54 (2)
Eu3—O3—O4^x	109.27 (2)	Eu4^ix—F2—O2^v	118.25 (2)
Eu3—O3—F1	80.746 (13)	Eu4^ix—F2—O3^xviii	111.179 (15)
Eu3—O3—O8	45.120 (9)	Eu4^ix—F2—O4^xx	55.042 (9)
Eu3—O3—F2^xi	74.236 (11)	Eu4^ix—F2—O6^xxi	56.337 (9)
Al1—O3—O1ⁱ	162.08 (3)	Eu4^ix—F2—O8^xxii	57.689 (10)
Al1—O3—O8	101.656 (15)	Al1^xviii—F2—Al2^xix	136.895 (19)
Al1—O3—O9	94.699 (16)	Al1^xviii—F2—O1^ix	146.080 (18)
O1ⁱ—O3—O2^vi	132.12 (2)	Al1^xviii—F2—O2^v	50.097 (9)
O1ⁱ—O3—O4^x	159.43 (2)	Al1^xviii—F2—O6^xxi	120.82 (2)
O1ⁱ—O3—F1	140.65 (2)	Al1^xviii—F2—O8^xxii	109.320 (15)
O1ⁱ—O3—O8	62.861 (9)	Al2^xix—F2—O1^ix	46.614 (7)
O1ⁱ—O3—O9	71.237 (11)	Al2^xix—F2—O2^v	143.71 (2)
O1ⁱ—O3—F2^xi	134.25 (2)	Al2^xix—F2—O3^xviii	102.254 (13)
O2^vi—O3—O4^x	65.580 (11)	Al2^xix—F2—O4^xx	119.997 (16)
O2^vi—O3—F1	53.180 (8)	Al2^xix—F2—O8^xxii	112.340 (16)
O2^vi—O3—O8	75.355 (11)	O1^ix—F2—O2^v	105.724 (16)
O2^vi—O3—O9	71.008 (11)	O1^ix—F2—O3^xviii	122.758 (14)
O4^x—O3—F1	55.396 (8)	O1^ix—F2—O4^xx	166.29 (2)
O4^x—O3—O8	123.400 (18)	O1^ix—F2—O6^xxi	83.697 (15)
O4^x—O3—O9	129.24 (2)	O1^ix—F2—O8^xxii	88.291 (12)
O4^x—O3—F2^xi	47.677 (7)	O2^v—F2—O3^xviii	71.237 (11)
F1—O3—O8	124.521 (15)	O2^v—F2—O4^xx	87.602 (15)
F1—O3—O9	78.017 (11)	O2^v—F2—O6^xxi	170.47 (3)
F1—O3—F2^xi	78.986 (10)	O2^v—F2—O8^xxii	84.829 (12)
O8—O3—O9	65.763 (11)	O3^xviii—F2—O4^xx	57.946 (8)
O8—O3—F2^xi	75.786 (10)	O3^xviii—F2—O6^xxi	102.676 (14)
O9—O3—F2^xi	109.709 (15)	O3^xviii—F2—O8^xxii	144.49 (2)
Eu2—O4—Eu3ⁱⁱ	99.877 (13)	O4^xx—F2—O6^xxi	82.913 (12)
Eu2—O4—Eu4^xiii	111.593 (14)	O4^xx—F2—O8^xxii	96.270 (13)
Eu2—O4—Al1^xiv	122.50 (2)	O6^xxi—F2—O8^xxii	97.071 (14)

Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z+1/2; (iii) x−1, y, z; (iv) −x, −y, −z+1; (v) −x, −y+1, −z+1; (vi) x, −y+1/2, z−1/2; (vii) x+1, −y+1/2, z−1/2; (viii) x+1, y, z; (ix) −x+1, −y+1, −z+1; (x) x, y, z−1; (xi) −x, y−1/2, −z+1/2; (xii) −x+1, y−1/2, −z+1/2; (xiii) x−1, −y+1/2, z+1/2; (xiv) x, y, z+1; (xv) −x, y−1/2, −z+3/2; (xvi) −x+1, y−1/2, −z+3/2; (xvii) x, y−1, z; (xviii) −x, y+1/2, −z+1/2; (xix) −x+1, y+1/2, −z+1/2; (xx) −x, y+1/2, −z+3/2; (xxi) −x+1, y+1/2, −z+3/2; (xxii) x, y+1, z.

(sm4al2o8f2) top

Crystal data top

Al₂F₂O₈Sm₄	V = 870.84 (17) Å³
M_r = 821.40	Z = 4
Monoclinic, P2₁/c	D_x = 6.265 Mg m⁻³
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.540600 Å
a = 7.6188 (8) Å	T = 298 K
b = 10.8705 (12) Å	white
c = 11.1077 (13) Å	Specimen preparation: Prepared at 298 K
β = 108.805 (8)°

Data collection top

Xpert diffractometer	Detector resolution: 3.2 pixels mm^-1
Radiation source: X-ray tube	Scan method: continuous
Secondary monochromator	2θ_min = 10.000°, 2θ_max = 150.000°, 2θ_step = 0.020°

Refinement top

R_p = 10.897	7001 data points
R_wp = 13.630	6 parameters
R_exp = 7.040	36 restraints
R_Bragg = 13.074

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Sm1	0.53040	0.08760	0.78990	0.00000*
Sm2	0.02700	0.07590	0.82430	0.00000*
Sm3	0.33260	0.13100	0.41400	0.00000*
Sm4	0.83890	0.13240	0.42840	0.00000*
Al1	0.19910	0.18370	0.13380	0.00000*
Al2	0.68210	0.18320	0.12120	0.00000*
O1	0.79010	0.23810	0.75230	0.00000*
O2	0.24410	0.20950	0.76760	0.00000*
O3	0.19410	0.01660	0.15620	0.00000*
O4	0.08530	0.23020	0.97910	0.00000*
F1	0.41410	0.22370	0.10700	0.00000*
O6	0.63950	0.22220	0.96710	0.00000*
O7	0.68220	0.01240	0.16020	0.00000*
O8	0.07210	−0.0044	0.40880	0.00000*
O9	0.53610	0.02170	0.40040	0.00000*
F2	0.05210	0.77110	0.34160	0.00000*	0.99000

Geometric parameters (Å, º) top

Sm1—O1	2.7016 (2)	O3—O2^vi	3.1996 (3)
Sm1—O2	2.4954 (2)	O3—O4^x	2.9828 (2)
Sm1—O3ⁱ	2.2885 (2)	O3—F1	2.9609 (2)
Sm1—F1ⁱⁱ	2.8213 (2)	O3—O9	3.0973 (4)
Sm1—O6	2.3772 (2)	O4—Sm2	2.3399 (2)
Sm1—O7ⁱ	2.1659 (2)	O4—Sm3ⁱⁱ	2.6885 (2)
Sm1—O9ⁱ	2.3337 (2)	O4—Sm4^xiii	2.3218 (2)
Sm2—O1ⁱⁱⁱ	2.4649 (2)	O4—Al1^xiv	1.7319 (2)
Sm2—O2	2.4317 (2)	O4—O1ⁱⁱⁱ	2.7856 (4)
Sm2—O3^iv	2.0324 (2)	O4—O2	2.9776 (3)
Sm2—O4	2.3399 (2)	O4—O2ⁱⁱ	3.1086 (4)
Sm2—O7ⁱ	2.3693 (2)	O4—O3^xiv	2.9828 (2)
Sm2—O8^iv	2.5725 (3)	O4—F1^xiv	2.4504 (3)
Sm2—F2^v	2.4102 (2)	O4—O8ⁱⁱ	3.0747 (3)
Sm3—Al1	3.0015 (4)	O4—F2^xv	2.5699 (2)
Sm3—O2^vi	2.3234 (2)	F1—Sm1^vi	2.8213 (2)
Sm3—O3	2.9853 (3)	F1—Sm3^vi	2.5725 (2)
Sm3—O4^vi	2.6885 (2)	F1—Al1	1.8098 (2)
Sm3—F1ⁱⁱ	2.5725 (2)	F1—Al2	2.0445 (2)
Sm3—O6^vi	2.7336 (2)	F1—O1^vi	2.8289 (3)
Sm3—O8	2.4566 (2)	F1—O2^vi	2.6223 (2)
Sm3—O9	1.9973 (1)	F1—O3	2.9609 (2)
Sm3—O9ⁱ	2.5839 (2)	F1—O4^x	2.4504 (3)
Sm4—O1^vi	2.3404 (2)	F1—O6^x	2.6617 (2)
Sm4—O4^vii	2.3218 (2)	F1—O7	3.0032 (2)
Sm4—O6^vi	2.3264 (2)	O6—Sm1	2.3772 (2)
Sm4—O7	3.1159 (3)	O6—Sm3ⁱⁱ	2.7336 (2)
Sm4—O8^viii	2.3801 (2)	O6—Sm4ⁱⁱ	2.3264 (2)
Sm4—O8ⁱ	2.2080 (2)	O6—Al2^xiv	1.6902 (2)
Sm4—O9	2.5307 (2)	O6—O1	2.9672 (3)
Sm4—F2^ix	2.6361 (3)	O6—O1ⁱⁱ	3.0323 (4)
Al1—Sm3	3.0015 (4)	O6—O2	3.1146 (4)
Al1—O2^vi	1.8291 (2)	O6—F1^xiv	2.6617 (2)
Al1—O3	1.8355 (2)	O6—O7^xiv	3.0754 (3)
Al1—O4^x	1.7319 (2)	O6—O9ⁱⁱ	2.9229 (3)
Al1—F1	1.8098 (2)	O6—F2^xvi	2.6645 (3)
Al1—F2^xi	2.2310 (2)	O7—Sm1ⁱ	2.1659 (2)
Al2—O1^vi	1.6604 (2)	O7—Sm2ⁱ	2.3693 (2)
Al2—F1	2.0445 (2)	O7—Sm4	3.1159 (3)
Al2—O6^x	1.6902 (2)	O7—Al2	1.9065 (2)
Al2—O7	1.9065 (2)	O7—O1^vi	2.9217 (3)
Al2—F2^xii	2.1553 (2)	O7—O2ⁱ	2.5469 (3)
O1—Sm1	2.7016 (2)	O7—F1	3.0032 (2)
O1—Sm2^viii	2.4649 (2)	O7—O6^x	3.0754 (3)
O1—Sm4ⁱⁱ	2.3404 (2)	O8—Sm2^iv	2.5725 (3)
O1—Al2ⁱⁱ	1.6604 (2)	O8—Sm3	2.4566 (2)
O1—O3ⁱ	2.9384 (3)	O8—Sm4ⁱⁱⁱ	2.3801 (2)
O1—O4^viii	2.7856 (4)	O8—Sm4ⁱ	2.2080 (2)
O1—F1ⁱⁱ	2.8289 (3)	O8—O4^vi	3.0747 (3)
O1—O6	2.9672 (3)	O8—O8^iv	2.5992 (3)
O1—O6^vi	3.0323 (4)	O8—O9ⁱ	3.0592 (4)
O1—O7ⁱⁱ	2.9217 (3)	O8—F2^xvii	2.5422 (3)
O1—F2^ix	1.8308 (2)	O9—Sm1ⁱ	2.3337 (2)
O2—Sm1	2.4954 (2)	O9—Sm3	1.9973 (1)
O2—Sm2	2.4317 (2)	O9—Sm3ⁱ	2.5839 (2)
O2—Sm3ⁱⁱ	2.3234 (2)	O9—Sm4	2.5307 (2)
O2—Al1ⁱⁱ	1.8291 (2)	O9—O3	3.0973 (4)
O2—O3ⁱⁱ	3.1996 (3)	O9—O6^vi	2.9229 (3)
O2—O4	2.9776 (3)	O9—O8ⁱ	3.0592 (4)
O2—O4^vi	3.1086 (4)	O9—O9ⁱ	2.4911 (3)
O2—F1ⁱⁱ	2.6223 (2)	F2—Sm2^v	2.4102 (2)
O2—O6	3.1146 (4)	F2—Sm4^ix	2.6361 (3)
O2—O7ⁱ	2.5469 (3)	F2—Al1^xviii	2.2310 (2)
O2—F2^v	2.2008 (3)	F2—Al2^xix	2.1553 (2)
O3—Sm1ⁱ	2.2885 (2)	F2—O1^ix	1.8308 (2)
O3—Sm2^iv	2.0324 (2)	F2—O2^v	2.2008 (3)
O3—Sm3	2.9853 (3)	F2—O4^xx	2.5698 (2)
O3—Al1	1.8355 (2)	F2—O6^xxi	2.6645 (3)
O3—O1ⁱ	2.9384 (3)	F2—O8^xxii	2.5422 (3)

O1—Sm1—O2	108.869 (17)	O4^x—O3—F1	48.692 (8)
O1—Sm1—O3ⁱ	71.609 (10)	O4^x—O3—O9	122.69 (2)
O1—Sm1—F1ⁱⁱ	61.579 (10)	F1—O3—O9	77.383 (12)
O1—Sm1—O6	71.170 (10)	Sm2—O4—Sm3ⁱⁱ	100.844 (13)
O1—Sm1—O7ⁱ	171.443 (18)	Sm2—O4—Sm4^xiii	109.621 (14)
O1—Sm1—O9ⁱ	97.139 (13)	Sm2—O4—Al1^xiv	115.83 (2)
O2—Sm1—O3ⁱ	170.93 (2)	Sm2—O4—O1ⁱⁱⁱ	56.690 (10)
O2—Sm1—F1ⁱⁱ	58.725 (8)	Sm2—O4—O2	52.785 (8)
O2—Sm1—O6	79.426 (13)	Sm2—O4—O2ⁱⁱ	145.83 (2)
O2—Sm1—O7ⁱ	65.798 (9)	Sm2—O4—O3^xiv	82.715 (14)
O2—Sm1—O9ⁱ	104.646 (13)	Sm2—O4—F1^xiv	108.773 (18)
O3ⁱ—Sm1—F1ⁱⁱ	126.651 (17)	Sm2—O4—O8ⁱⁱ	121.69 (2)
O3ⁱ—Sm1—O6	92.385 (12)	Sm2—O4—F2^xv	131.704 (19)
O3ⁱ—Sm1—O7ⁱ	112.528 (18)	Sm3ⁱⁱ—O4—Sm4^xiii	98.956 (15)
O3ⁱ—Sm1—O9ⁱ	84.145 (15)	Sm3ⁱⁱ—O4—Al1^xiv	105.103 (14)
F1ⁱⁱ—Sm1—O6	95.368 (17)	Sm3ⁱⁱ—O4—O1ⁱⁱⁱ	99.845 (16)
F1ⁱⁱ—Sm1—O7ⁱ	117.516 (15)	Sm3ⁱⁱ—O4—O2	48.084 (8)
F1ⁱⁱ—Sm1—O9ⁱ	77.985 (12)	Sm3ⁱⁱ—O4—O2ⁱⁱ	94.894 (16)
O6—Sm1—O7ⁱ	100.822 (13)	Sm3ⁱⁱ—O4—O3^xiv	122.984 (15)
O6—Sm1—O9ⁱ	168.30 (2)	Sm3ⁱⁱ—O4—F1^xiv	59.867 (10)
O7ⁱ—Sm1—O9ⁱ	90.822 (14)	Sm3ⁱⁱ—O4—O8ⁱⁱ	49.910 (8)
O1ⁱⁱⁱ—Sm2—O2	88.671 (13)	Sm3ⁱⁱ—O4—F2^xv	127.389 (18)
O1ⁱⁱⁱ—Sm2—O3^iv	80.974 (12)	Sm4^xiii—O4—Al1^xiv	122.375 (18)
O1ⁱⁱⁱ—Sm2—O4	70.813 (12)	Sm4^xiii—O4—O1ⁱⁱⁱ	53.617 (10)
O1ⁱⁱⁱ—Sm2—O7ⁱ	152.024 (19)	Sm4^xiii—O4—O2	111.078 (15)
O1ⁱⁱⁱ—Sm2—O8^iv	86.727 (11)	Sm4^xiii—O4—O2ⁱⁱ	97.468 (18)
O2—Sm2—O3^iv	168.347 (18)	Sm4^xiii—O4—O3^xiv	133.775 (18)
O2—Sm2—O4	77.195 (11)	Sm4^xiii—O4—F1^xiv	139.00 (2)
O2—Sm2—O7ⁱ	64.061 (9)	Sm4^xiii—O4—O8ⁱⁱ	49.989 (8)
O2—Sm2—O8^iv	85.597 (12)	Sm4^xiii—O4—F2^xv	64.987 (10)
O2—Sm2—F2^v	54.068 (9)	Al1^xiv—O4—O1ⁱⁱⁱ	155.00 (3)
O3^iv—Sm2—O4	104.114 (14)	Al1^xiv—O4—O2	124.05 (2)
O3^iv—Sm2—O7ⁱ	125.42 (2)	Al1^xiv—O4—F1^xiv	47.551 (10)
O3^iv—Sm2—O8^iv	88.473 (14)	Al1^xiv—O4—O8ⁱⁱ	119.990 (19)
O3^iv—Sm2—F2^v	114.288 (14)	Al1^xiv—O4—F2^xv	58.686 (10)
O4—Sm2—O7ⁱ	106.586 (13)	O1ⁱⁱⁱ—O4—O2	72.767 (13)
O4—Sm2—O8^iv	151.74 (2)	O1ⁱⁱⁱ—O4—O2ⁱⁱ	149.13 (3)
O4—Sm2—F2^v	90.495 (16)	O1ⁱⁱⁱ—O4—O3^xiv	126.31 (2)
O7ⁱ—Sm2—O8^iv	85.120 (16)	O1ⁱⁱⁱ—O4—F1^xiv	154.39 (3)
O7ⁱ—Sm2—F2^v	109.427 (15)	O1ⁱⁱⁱ—O4—O8ⁱⁱ	77.857 (12)
O8^iv—Sm2—F2^v	61.252 (10)	O1ⁱⁱⁱ—O4—F2^xv	106.48 (2)
Al1—Sm3—O4^vi	98.000 (16)	O2—O4—O2ⁱⁱ	135.01 (2)
Al1—Sm3—F1ⁱⁱ	131.07 (2)	O2—O4—O3^xiv	111.365 (17)
Al1—Sm3—O6^vi	95.319 (17)	O2—O4—F1^xiv	81.709 (16)
Al1—Sm3—O8	95.096 (13)	O2—O4—O8ⁱⁱ	82.023 (11)
Al1—Sm3—O9	92.691 (15)	O2—O4—F2^xv	174.36 (2)
Al1—Sm3—O9ⁱ	149.84 (2)	O2ⁱⁱ—O4—O3^xiv	63.333 (10)
O2^vi—Sm3—O3	72.927 (11)	O2ⁱⁱ—O4—F1^xiv	54.757 (11)
O2^vi—Sm3—O4^vi	72.483 (10)	O2ⁱⁱ—O4—O8ⁱⁱ	91.570 (15)
O2^vi—Sm3—F1ⁱⁱ	93.595 (17)	O3^xiv—O4—F1^xiv	65.187 (10)
O2^vi—Sm3—O6^vi	75.549 (13)	O3^xiv—O4—O8ⁱⁱ	154.36 (2)
O2^vi—Sm3—O8	112.375 (14)	O3^xiv—O4—F2^xv	73.716 (10)
O2^vi—Sm3—O9	116.628 (15)	F1^xiv—O4—O8ⁱⁱ	96.825 (14)
O2^vi—Sm3—O9ⁱ	171.18 (2)	F1^xiv—O4—F2^xv	98.706 (16)
O3—Sm3—O4^vi	115.476 (15)	O8ⁱⁱ—O4—F2^xv	92.347 (12)
O3—Sm3—F1ⁱⁱ	166.13 (2)	Sm1^vi—F1—Sm3^vi	95.111 (17)
O3—Sm3—O6^vi	117.609 (17)	Sm1^vi—F1—Al1	98.457 (14)
O3—Sm3—O8	72.228 (11)	Sm1^vi—F1—Al2	91.546 (12)
O3—Sm3—O9	73.896 (14)	Sm1^vi—F1—O1^vi	57.128 (9)
O3—Sm3—O9ⁱ	115.08 (2)	Sm1^vi—F1—O2^vi	54.419 (8)
O4^vi—Sm3—F1ⁱⁱ	55.466 (9)	Sm1^vi—F1—O3	119.011 (16)
O4^vi—Sm3—O6^vi	103.840 (16)	Sm1^vi—F1—O4^x	114.936 (19)
O4^vi—Sm3—O8	73.241 (11)	Sm1^vi—F1—O6^x	108.234 (15)
O4^vi—Sm3—O9	169.296 (18)	Sm1^vi—F1—O7	112.246 (16)
O4^vi—Sm3—O9ⁱ	105.699 (14)	Sm3^vi—F1—Al1	107.245 (14)
F1ⁱⁱ—Sm3—O6^vi	60.124 (9)	Sm3^vi—F1—Al2	99.397 (15)
F1ⁱⁱ—Sm3—O8	111.322 (15)	Sm3^vi—F1—O1^vi	108.26 (2)
F1ⁱⁱ—Sm3—O9	116.330 (14)	Sm3^vi—F1—O2^vi	110.941 (18)
F1ⁱⁱ—Sm3—O9ⁱ	78.590 (12)	Sm3^vi—F1—O3	128.441 (16)
O6^vi—Sm3—O8	169.49 (2)	Sm3^vi—F1—O4^x	64.667 (10)
O6^vi—Sm3—O9	74.499 (11)	Sm3^vi—F1—O6^x	62.940 (9)
O6^vi—Sm3—O9ⁱ	96.813 (12)	Sm3^vi—F1—O7	126.850 (17)
O8—Sm3—O9	106.425 (17)	Al1—F1—Al2	150.45 (2)
O8—Sm3—O9ⁱ	74.688 (12)	Al1—F1—O1^vi	138.18 (2)
O9—Sm3—O9ⁱ	64.398 (10)	Al1—F1—O6^x	152.02 (2)
O1^vi—Sm4—O4^vii	73.379 (12)	Al1—F1—O7	112.218 (17)
O1^vi—Sm4—O6^vi	78.960 (11)	Al2—F1—O2^vi	135.000 (19)
O1^vi—Sm4—O7	62.873 (10)	Al2—F1—O3	115.640 (16)
O1^vi—Sm4—O8^viii	102.799 (13)	Al2—F1—O4^x	149.30 (3)
O1^vi—Sm4—O8ⁱ	170.99 (2)	O1^vi—F1—O2^vi	101.690 (17)
O1^vi—Sm4—O9	106.881 (13)	O1^vi—F1—O3	122.391 (17)
O1^vi—Sm4—F2^ix	119.09 (2)	O1^vi—F1—O4^x	169.90 (3)
O4^vii—Sm4—O6^vi	92.477 (14)	O1^vi—F1—O6^x	66.966 (12)
O4^vii—Sm4—O7	122.132 (18)	O1^vi—F1—O7	60.039 (10)
O4^vii—Sm4—O8^viii	81.667 (12)	O2^vi—F1—O3	69.627 (10)
O4^vii—Sm4—O8ⁱ	101.298 (13)	O2^vi—F1—O4^x	75.500 (14)
O4^vii—Sm4—O9	165.81 (2)	O2^vi—F1—O6^x	162.17 (2)
O4^vii—Sm4—F2^ix	62.059 (10)	O2^vi—F1—O7	122.119 (15)
O6^vi—Sm4—O7	112.913 (15)	O3—F1—O4^x	66.120 (10)
O6^vi—Sm4—O8^viii	173.025 (18)	O3—F1—O6^x	127.825 (16)
O6^vi—Sm4—O8ⁱ	108.859 (14)	O3—F1—O7	76.805 (11)
O6^vi—Sm4—O9	73.862 (11)	O4^x—F1—O6^x	113.147 (19)
O6^vi—Sm4—F2^ix	64.598 (11)	O4^x—F1—O7	129.76 (2)
O7—Sm4—O8^viii	73.634 (13)	O6^x—F1—O7	65.436 (9)
O7—Sm4—O8ⁱ	116.17 (2)	Sm1—O6—Sm3ⁱⁱ	97.712 (12)
O7—Sm4—O9	68.301 (11)	Sm1—O6—Sm4ⁱⁱ	109.880 (14)
O7—Sm4—F2^ix	175.63 (3)	Sm1—O6—Al2^xiv	125.86 (2)
O8^viii—Sm4—O8ⁱ	68.897 (10)	Sm1—O6—O1	59.516 (9)
O8^viii—Sm4—O9	111.682 (18)	Sm1—O6—O1ⁱⁱ	150.02 (3)
O8^viii—Sm4—F2^ix	109.028 (14)	Sm1—O6—O2	51.959 (10)
O8ⁱ—Sm4—O9	80.103 (14)	Sm1—O6—F1^xiv	111.590 (17)
O8ⁱ—Sm4—F2^ix	62.575 (10)	Sm1—O6—O7^xiv	92.933 (16)
O9—Sm4—F2^ix	107.352 (16)	Sm1—O6—O9ⁱⁱ	112.496 (18)
Sm3—Al1—O2^vi	50.690 (10)	Sm1—O6—F2^xvi	140.01 (2)
Sm3—Al1—O3	71.666 (14)	Sm3ⁱⁱ—O6—Sm4ⁱⁱ	97.332 (15)
Sm3—Al1—O4^x	168.09 (3)	Sm3ⁱⁱ—O6—Al2^xiv	103.686 (16)
Sm3—Al1—F1	101.203 (18)	Sm3ⁱⁱ—O6—O1	108.547 (15)
Sm3—Al1—F2^xi	88.373 (15)	Sm3ⁱⁱ—O6—O1ⁱⁱ	98.721 (18)
O2^vi—Al1—O3	121.644 (19)	Sm3ⁱⁱ—O6—O2	46.251 (9)
O2^vi—Al1—O4^x	121.58 (2)	Sm3ⁱⁱ—O6—F1^xiv	56.936 (9)
O2^vi—Al1—F1	92.214 (13)	Sm3ⁱⁱ—O6—O7^xiv	118.309 (16)
O2^vi—Al1—F2^xi	64.767 (11)	Sm3ⁱⁱ—O6—F2^xvi	121.92 (2)
O3—Al1—O4^x	113.435 (16)	Sm4ⁱⁱ—O6—Al2^xiv	115.715 (15)
O3—Al1—F1	108.633 (14)	Sm4ⁱⁱ—O6—O1	50.729 (8)
O3—Al1—F2^xi	110.410 (15)	Sm4ⁱⁱ—O6—O1ⁱⁱ	92.673 (15)
O4^x—Al1—F1	87.527 (16)	Sm4ⁱⁱ—O6—O2	115.983 (19)
O4^x—Al1—F2^xi	79.769 (13)	Sm4ⁱⁱ—O6—F1^xiv	133.344 (17)
F1—Al1—F2^xi	140.85 (2)	Sm4ⁱⁱ—O6—O7^xiv	134.761 (17)
O1^vi—Al2—F1	99.030 (18)	Sm4ⁱⁱ—O6—O9ⁱⁱ	56.272 (9)
O1^vi—Al2—O6^x	129.64 (2)	Sm4ⁱⁱ—O6—F2^xvi	63.340 (11)
O1^vi—Al2—O7	109.798 (17)	Al2^xiv—O6—O1	146.22 (3)
O1^vi—Al2—F2^xii	55.533 (9)	Al2^xiv—O6—O2	122.37 (3)
F1—Al2—O6^x	90.394 (14)	Al2^xiv—O6—F1^xiv	50.186 (10)
F1—Al2—O7	98.886 (14)	Al2^xiv—O6—O9ⁱⁱ	116.339 (18)
F1—Al2—F2^xii	140.59 (2)	Al2^xiv—O6—F2^xvi	53.866 (11)
O6^x—Al2—O7	117.404 (16)	O1—O6—O1ⁱⁱ	135.86 (2)
O6^x—Al2—F2^xii	86.835 (16)	O1—O6—O2	88.080 (15)
O7—Al2—F2^xii	117.172 (16)	O1—O6—F1^xiv	163.46 (2)
Sm1—O1—Sm2^viii	90.735 (14)	O1—O6—O7^xiv	128.509 (18)
Sm1—O1—Sm4ⁱⁱ	99.323 (13)	O1—O6—O9ⁱⁱ	83.292 (11)
Sm1—O1—Al2ⁱⁱ	105.486 (14)	O1—O6—F2^xvi	99.177 (19)
Sm1—O1—O3ⁱ	47.648 (8)	O1ⁱⁱ—O6—O2	134.67 (3)
Sm1—O1—O4^viii	105.045 (17)	O1ⁱⁱ—O6—F1^xiv	59.154 (11)
Sm1—O1—F1ⁱⁱ	61.294 (9)	O1ⁱⁱ—O6—O7^xiv	57.151 (10)
Sm1—O1—O6	49.314 (8)	O1ⁱⁱ—O6—O9ⁱⁱ	96.290 (15)
Sm1—O1—O6^vi	101.440 (15)	O2—O6—F1^xiv	75.970 (14)
Sm1—O1—O7ⁱⁱ	118.611 (17)	O2—O6—O7^xiv	108.902 (18)
Sm1—O1—F2^ix	134.682 (18)	O2—O6—O9ⁱⁱ	75.051 (12)
Sm2^viii—O1—Sm4ⁱⁱ	104.872 (14)	O2—O6—F2^xvi	168.03 (3)
Sm2^viii—O1—Al2ⁱⁱ	139.214 (19)	F1^xiv—O6—O7^xiv	62.643 (9)
Sm2^viii—O1—O4^viii	52.498 (9)	F1^xiv—O6—O9ⁱⁱ	88.295 (12)
Sm2^viii—O1—F1ⁱⁱ	142.28 (2)	F1^xiv—O6—F2^xvi	95.867 (16)
Sm2^viii—O1—O6	97.466 (13)	O7^xiv—O6—O9ⁱⁱ	147.39 (2)
Sm2^viii—O1—O6^vi	115.574 (19)	O7^xiv—O6—F2^xvi	73.973 (11)
Sm2^viii—O1—O7ⁱⁱ	150.65 (2)	O9ⁱⁱ—O6—F2^xvi	96.227 (15)
Sm2^viii—O1—F2^ix	66.367 (9)	Sm1ⁱ—O7—Sm2ⁱ	122.479 (19)
Sm4ⁱⁱ—O1—Al2ⁱⁱ	108.87 (2)	Sm1ⁱ—O7—Sm4	93.044 (14)
Sm4ⁱⁱ—O1—O3ⁱ	107.452 (18)	Sm1ⁱ—O7—Al2	126.967 (16)
Sm4ⁱⁱ—O1—O4^viii	53.004 (10)	Sm1ⁱ—O7—O1^vi	121.703 (17)
Sm4ⁱⁱ—O1—F1ⁱⁱ	104.322 (19)	Sm1ⁱ—O7—O2ⁱ	63.336 (9)
Sm4ⁱⁱ—O1—O6	50.311 (8)	Sm1ⁱ—O7—F1	85.234 (13)
Sm4ⁱⁱ—O1—O6^vi	133.81 (3)	Sm1ⁱ—O7—O6^x	129.121 (16)
Sm4ⁱⁱ—O1—O7ⁱⁱ	71.654 (11)	Sm2ⁱ—O7—Sm4	92.236 (13)
Sm4ⁱⁱ—O1—F2^ix	123.535 (18)	Sm2ⁱ—O7—Al2	110.055 (15)
Al2ⁱⁱ—O1—O3ⁱ	137.93 (2)	Sm2ⁱ—O7—O1^vi	101.517 (15)
Al2ⁱⁱ—O1—O4^viii	146.76 (3)	Sm2ⁱ—O7—O2ⁱ	59.159 (9)
Al2ⁱⁱ—O1—F1ⁱⁱ	45.542 (10)	Sm2ⁱ—O7—F1	152.240 (19)
Al2ⁱⁱ—O1—O6	121.63 (2)	Sm2ⁱ—O7—O6^x	103.729 (14)
Al2ⁱⁱ—O1—F2^ix	76.071 (11)	Sm4—O7—Al2	77.379 (15)
O3ⁱ—O1—O4^viii	74.159 (11)	Sm4—O7—O1^vi	45.473 (9)
O3ⁱ—O1—F1ⁱⁱ	104.874 (15)	Sm4—O7—O2ⁱ	96.766 (14)
O3ⁱ—O1—O6	69.533 (10)	Sm4—O7—F1	83.951 (14)
O3ⁱ—O1—O6^vi	117.063 (17)	Sm4—O7—O6^x	106.150 (19)
O3ⁱ—O1—O7ⁱⁱ	166.25 (2)	Al2—O7—O2ⁱ	167.91 (3)
O3ⁱ—O1—F2^ix	100.625 (14)	O1^vi—O7—O2ⁱ	139.49 (2)
O4^viii—O1—F1ⁱⁱ	153.43 (3)	O1^vi—O7—F1	57.020 (9)
O4^viii—O1—O6	71.322 (12)	O1^vi—O7—O6^x	60.683 (10)
O4^viii—O1—O6^vi	150.75 (3)	O2ⁱ—O7—F1	148.57 (2)
O4^viii—O1—O7ⁱⁱ	113.535 (17)	O2ⁱ—O7—O6^x	152.25 (2)
O4^viii—O1—F2^ix	91.519 (18)	F1—O7—O6^x	51.921 (8)
F1ⁱⁱ—O1—O6	83.360 (15)	Sm2^iv—O8—Sm3	100.222 (15)
F1ⁱⁱ—O1—O6^vi	53.880 (11)	Sm2^iv—O8—Sm4ⁱⁱⁱ	107.174 (14)
F1ⁱⁱ—O1—O7ⁱⁱ	62.941 (10)	Sm2^iv—O8—Sm4ⁱ	123.16 (2)
F1ⁱⁱ—O1—F2^ix	114.40 (2)	Sm2^iv—O8—O4^vi	121.565 (17)
O6—O1—O6^vi	137.24 (2)	Sm2^iv—O8—O8^iv	137.31 (2)
O6—O1—O7ⁱⁱ	101.393 (14)	Sm2^iv—O8—O9ⁱ	125.66 (2)
O6—O1—F2^ix	161.83 (2)	Sm2^iv—O8—F2^xvii	56.225 (10)
O6^vi—O1—O7ⁱⁱ	62.165 (10)	Sm3—O8—Sm4ⁱⁱⁱ	104.167 (16)
O6^vi—O1—F2^ix	60.621 (12)	Sm3—O8—Sm4ⁱ	109.015 (13)
O7ⁱⁱ—O1—F2^ix	90.776 (13)	Sm3—O8—O4^vi	56.850 (8)
Sm1—O2—Sm2	107.634 (16)	Sm3—O8—O8^iv	120.059 (16)
Sm1—O2—Sm3ⁱⁱ	106.238 (13)	Sm3—O8—O9ⁱ	54.552 (9)
Sm1—O2—Al1ⁱⁱ	110.280 (15)	Sm3—O8—F2^xvii	123.612 (18)
Sm1—O2—O3ⁱⁱ	121.590 (17)	Sm4ⁱⁱⁱ—O8—Sm4ⁱ	111.103 (14)
Sm1—O2—O4	121.756 (17)	Sm4ⁱⁱⁱ—O8—O4^vi	48.344 (8)
Sm1—O2—O4^vi	104.572 (17)	Sm4ⁱⁱⁱ—O8—O8^iv	52.422 (8)
Sm1—O2—F1ⁱⁱ	66.856 (9)	Sm4ⁱⁱⁱ—O8—O9ⁱ	124.44 (2)
Sm1—O2—O6	48.615 (9)	Sm4ⁱⁱⁱ—O8—F2^xvii	130.601 (18)
Sm1—O2—O7ⁱ	50.866 (8)	Sm4ⁱ—O8—O4^vi	115.254 (19)
Sm1—O2—F2^v	144.47 (2)	Sm4ⁱ—O8—O8^iv	58.681 (9)
Sm2—O2—Sm3ⁱⁱ	109.425 (14)	Sm4ⁱ—O8—O9ⁱ	54.579 (10)
Sm2—O2—Al1ⁱⁱ	128.647 (15)	Sm4ⁱ—O8—F2^xvii	66.986 (11)
Sm2—O2—O3ⁱⁱ	130.526 (18)	O4^vi—O8—O8^iv	75.747 (11)
Sm2—O2—O4	50.021 (8)	O4^vi—O8—O9ⁱ	86.498 (13)
Sm2—O2—O4^vi	108.768 (16)	O4^vi—O8—F2^xvii	177.63 (3)
Sm2—O2—F1ⁱⁱ	150.216 (18)	O8^iv—O8—O9ⁱ	91.459 (15)
Sm2—O2—O6	115.140 (19)	O8^iv—O8—F2^xvii	105.296 (14)
Sm2—O2—O7ⁱ	56.779 (9)	O9ⁱ—O8—F2^xvii	95.575 (15)
Sm2—O2—F2^v	62.468 (10)	Sm1ⁱ—O9—Sm3	115.100 (14)
Sm3ⁱⁱ—O2—Al1ⁱⁱ	91.784 (16)	Sm1ⁱ—O9—Sm3ⁱ	108.11 (2)
Sm3ⁱⁱ—O2—O3ⁱⁱ	63.113 (10)	Sm1ⁱ—O9—Sm4	106.055 (15)
Sm3ⁱⁱ—O2—O4	59.432 (9)	Sm1ⁱ—O9—O3	47.307 (10)
Sm3ⁱⁱ—O2—O4^vi	119.53 (2)	Sm1ⁱ—O9—O6^vi	132.578 (18)
Sm3ⁱⁱ—O2—F1ⁱⁱ	100.017 (16)	Sm1ⁱ—O9—O8ⁱ	118.34 (2)
Sm3ⁱⁱ—O2—O6	58.200 (10)	Sm1ⁱ—O9—O9ⁱ	131.49 (2)
Sm3ⁱⁱ—O2—O7ⁱ	120.11 (2)	Sm3—O9—Sm3ⁱ	115.602 (15)
Sm3ⁱⁱ—O2—F2^v	109.202 (18)	Sm3—O9—Sm4	114.013 (19)
Al1ⁱⁱ—O2—O4	125.15 (2)	Sm3—O9—O3	67.820 (12)
Al1ⁱⁱ—O2—O6	115.78 (2)	Sm3—O9—O6^vi	64.317 (9)
Al1ⁱⁱ—O2—O7ⁱ	145.24 (2)	Sm3—O9—O8ⁱ	126.30 (2)
Al1ⁱⁱ—O2—F2^v	66.487 (10)	Sm3—O9—O9ⁱ	69.295 (10)
O3ⁱⁱ—O2—O4	101.935 (14)	Sm3ⁱ—O9—Sm4	95.986 (12)
O3ⁱⁱ—O2—O4^vi	56.416 (10)	Sm3ⁱ—O9—O3	133.41 (2)
O3ⁱⁱ—O2—F1ⁱⁱ	60.170 (9)	Sm3ⁱ—O9—O6^vi	113.968 (18)
O3ⁱⁱ—O2—O6	101.606 (15)	Sm3ⁱ—O9—O8ⁱ	50.760 (9)
O3ⁱⁱ—O2—O7ⁱ	171.81 (2)	Sm3ⁱ—O9—O9ⁱ	46.308 (8)
O3ⁱⁱ—O2—F2^v	74.013 (12)	Sm4—O9—O3	126.32 (2)
O4—O2—O4^vi	132.48 (2)	Sm4—O9—O6^vi	49.866 (8)
O4—O2—F1ⁱⁱ	158.62 (2)	Sm4—O9—O8ⁱ	45.318 (9)
O4—O2—O6	88.917 (15)	Sm4—O9—O9ⁱ	115.750 (15)
O4—O2—O7ⁱ	85.845 (11)	O3—O9—O6^vi	108.720 (17)
O4—O2—F2^v	79.768 (15)	O3—O9—O8ⁱ	164.39 (3)
O4^vi—O2—F1ⁱⁱ	49.743 (10)	O3—O9—O9ⁱ	114.22 (2)
O4^vi—O2—O6	133.62 (3)	O6^vi—O9—O8ⁱ	76.106 (12)
O4^vi—O2—O7ⁱ	119.825 (18)	O6^vi—O9—O9ⁱ	94.237 (13)
O4^vi—O2—F2^v	54.721 (11)	O8ⁱ—O9—O9ⁱ	79.546 (14)
F1ⁱⁱ—O2—O6	83.984 (16)	Sm2^v—F2—Sm4^ix	112.92 (2)
F1ⁱⁱ—O2—O7ⁱ	111.676 (14)	Sm2^v—F2—Al1^xviii	111.997 (13)
F1ⁱⁱ—O2—F2^v	104.010 (16)	Sm2^v—F2—Al2^xix	116.131 (16)
O6—O2—O7ⁱ	75.726 (12)	Sm2^v—F2—O1^ix	69.536 (10)
O6—O2—F2^v	166.56 (3)	Sm2^v—F2—O2^v	63.465 (10)
O7ⁱ—O2—F2^v	110.311 (16)	Sm2^v—F2—O4^xx	130.390 (19)
Sm1ⁱ—O3—Sm2^iv	116.683 (19)	Sm2^v—F2—O6^xxi	133.34 (2)
Sm1ⁱ—O3—Sm3	86.815 (12)	Sm2^v—F2—O8^xxii	62.523 (10)
Sm1ⁱ—O3—Al1	117.900 (17)	Sm4^ix—F2—Al1^xviii	93.753 (14)
Sm1ⁱ—O3—O1ⁱ	60.743 (9)	Sm4^ix—F2—Al2^xix	90.437 (12)
Sm1ⁱ—O3—O2^vi	112.000 (17)	Sm4^ix—F2—O1^ix	120.95 (2)
Sm1ⁱ—O3—O4^x	126.464 (17)	Sm4^ix—F2—O2^v	116.28 (2)
Sm1ⁱ—O3—F1	84.179 (13)	Sm4^ix—F2—O4^xx	52.954 (9)
Sm1ⁱ—O3—O9	48.549 (10)	Sm4^ix—F2—O6^xxi	52.062 (10)
Sm2^iv—O3—Sm3	98.783 (15)	Sm4^ix—F2—O8^xxii	50.439 (9)
Sm2^iv—O3—Al1	123.930 (17)	Al1^xviii—F2—Al2^xix	125.30 (2)
Sm2^iv—O3—O1ⁱ	55.939 (9)	Al1^xviii—F2—O1^ix	142.50 (2)
Sm2^iv—O3—O2^vi	114.747 (18)	Al1^xviii—F2—O2^v	48.747 (9)
Sm2^iv—O3—O4^x	113.062 (15)	Al1^xviii—F2—O6^xxi	112.84 (2)
Sm2^iv—O3—F1	159.032 (18)	Al1^xviii—F2—O8^xxii	110.209 (16)
Sm2^iv—O3—O9	114.06 (2)	Al2^xix—F2—O1^ix	48.396 (8)
Sm3—O3—Al1	72.627 (14)	Al2^xix—F2—O2^v	151.80 (2)
Sm3—O3—O1ⁱ	95.643 (15)	Al2^xix—F2—O4^xx	111.531 (16)
Sm3—O3—O4^x	104.211 (19)	Al2^xix—F2—O8^xxii	113.930 (16)
Sm3—O3—F1	79.294 (12)	O1^ix—F2—O2^v	115.86 (2)
Al1—O3—O1ⁱ	168.25 (3)	O1^ix—F2—O4^xx	159.79 (2)
Al1—O3—O9	93.017 (17)	O1^ix—F2—O6^xxi	82.601 (16)
O1ⁱ—O3—O2^vi	139.16 (2)	O1^ix—F2—O8^xxii	103.386 (14)
O1ⁱ—O3—O4^x	158.95 (2)	O2^v—F2—O4^xx	80.923 (15)
O1ⁱ—O3—F1	144.86 (2)	O2^v—F2—O6^xxi	160.49 (3)
O1ⁱ—O3—O9	77.576 (12)	O2^v—F2—O8^xxii	91.352 (13)
O2^vi—O3—O4^x	60.251 (10)	O4^xx—F2—O6^xxi	79.760 (13)
O2^vi—O3—F1	50.203 (8)	O4^xx—F2—O8^xxii	86.524 (12)
O2^vi—O3—O9	71.517 (11)	O6^xxi—F2—O8^xxii	90.193 (13)

Funding information

This research was funded by the Ministerio de Economía, Industria y Competitividad (MAT2016-76739-R) (AEI/FEDER, UE), and Departamento de Educación of the Basque Government (IT-630–13). The authors thank SGIker of UPV/EHU for technical and personnel support. A. Morán-Ruiz thanks UPV/EHU for funding.

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IUCrJ

Volume 6| Part 1| January 2019| Pages 128-135

ISSN: 2052-2525

https://doi.org/10.1107/S205225251801744X

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