research communications
Hydroflux synthesis and 3IO
of TlaTechnische Universität Dresden, Chair of Inorganic Chemistry II, Bergstrasse 66, 01069 Dresden, Germany, and bMax-Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
*Correspondence e-mail: michael.ruck@tu-dresden.de
Single-crystals of thallium(I) iodide oxide Tl3IO were obtained as by-product in a hydroflux synthesis at 473 K for 10 h. A potassium hydroxide hydroflux with a water-base molar ratio of 1.6 and the starting materials TlNO3, RhI3 and Ba(NO3)2 was used, resulting in a few black needle-shaped crystals. X-ray diffraction on a single-crystal revealed the hexagonal P63/mmc (No. 194) with lattice parameters a = 7.1512 (3) Å and c = 6.3639 (3) Å. Tl3IO crystallizes as hexagonal anti-perovskite (anti-BaNiO3 type) and is thus structurally related to the alkali-metal halide/auride oxides M3XO (M = K, Rb, Cs; X = Cl, Br, I, Au). The oxygen atoms center thallium octahedra. The [OTl6] octahedra share trans faces, forming a linear chain along [001]. Twelve thallium atoms surround each iodine atom in an [ITl12] anti-cuboctahedron. Thallium and iodine atoms together form a hexagonal close-sphere packing, in which every fourth octahedral void is occupied by oxygen.
Keywords: crystal structure; hydroflux synthesis; thallium; oxide iodide; single-crystal XRD.
CCDC reference: 2030857
1. Chemical context
The class of alkali-metal halide/auride oxides comprises several compounds with the general formula M3XO (M = K, Rb, Cs; X = Cl, Br, I, Au) (Sitta et al., 1991a,b; Feldmann & Jansen, 1995a,b,c; Sabrowsky et al., 1996), Li3BrO (Wortmann et al., 1989), Na3X′O (X′ = Cl, Br) (Sabrowsky et al., 1988; Hippler et al., 1990). These ternary oxides crystallize typically as anti-perovskites, i.e. in the cubic anti-CaTiO3 type. The cesium derivatives Cs3BrO, Cs3IO and Cs3AuO adopt hexagonal anti-perovskite structures (anti-BaNiO3 type), whereas the Cs3ClO crystallizes as anti-NH4CdCl3 type and thus does not form a perovskite structure. The of Rb3IO has both face and corner-sharing [ORb6] octahedra (anti-BaFeO3–x type). The adopted structure type depends on the size of the alkali-metal and halide/auride ions and their ratio. The stability range of the different perovskite phases can be estimated by using Goldschmidt's tolerance factor, where larger M and X ions tend to destabilize the cubic anti-perovskite structure resulting in the hexagonal polymorph (Babel, 1969; Feldmann & Jansen, 1995b).
For the synthesis of the title compound, the hydroflux method was used, which can be classified as intermediate between hydrothermal and et al., 2013). An approximately equimolar mixture of alkali-metal hydroxide (typically NaOH or KOH) and water is used as reaction medium (Albrecht et al., 2020a). Good solubility of oxides and hydroxides, highly crystalline reaction products suitable for single-crystal X-ray comparably low reaction temperatures and a pressureless setup are essential advantages of the hydroflux method. In this communication, we report on the synthesis and analysis of the thallium(I) iodide oxide Tl3IO.
synthesis (Chance2. Structural commentary
Single-crystal X-ray diffraction on a black needle revealed the composition Tl3IO and a hexagonal structure in the P63/mmc (no. 194) with lattice parameters a = 7.1512 (3) Å and c = 6.3639 (3) Å at 100 (1) K. Tl3IO crystallizes as hexagonal anti-perovskite (anti-BaNiO3 type; Fig. 1, Tables 1 and 2). The consists of three atoms, thallium (site symmetry mm2, 6h), iodine (m2, 2d) and oxygen (m., 2a). The oxygen atoms center thallium octahedra. The [OTl6] octahedra share trans faces, forming a linear chain along [001]. Twelve thallium atoms surround each iodine atom in a [ITl12] anti-cuboctahedron (triangular orthobicupola). Thallium and iodine atoms together form a hexagonal close-sphere packing, in which every fourth octahedral void is occupied by oxygen. Thus, also the thallium atom centers an anti-cuboctahedron, which has the composition [Tl(I4Tl8)].
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The [OTl6] octahedron is slightly elongated along the chain direction. The O—Tl bond length of 2.549 (1) Å is about 1% longer than in Tl2O, at 2.517 (1) Å (Sabrowsky, 1971). The Tl—O—Tl angles along the chain parallel to c are 94.8 (1)°. The shortest Tl⋯Tl distances in Tl3IO are with 3.449 (1) Å, very similar to those in thallium metal, which has Tl⋯Tl distances of 3.405 (1) and 3.455 (1) Å in its hexagonal sphere packing (Barrett, 1958). Accordingly, the [ITl12] anticuboctahedra are also stretched along [001], with Tl—I distances of 3.576 (1) Å and 3.833 (1) Å. Although thallium(I) has a larger ionic radius (1.70 Å for c.n. = 12; Shannon, 1976) than potassium (1.64 Å for c.n. = 12), the M—O, M⋯M and the average M—I distances in Tl3IO are smaller than in K3IO by 3.5%, 7.5% and 1%, respectively (Feldmann & Jansen, 1995b).
3. Synthesis and crystallization
Thallium(I) iodide oxide, Tl3IO, was synthesized in a potassium hydroxide hydroflux. The reaction was carried out in a PTFE-lined 50 mL Berghof type DAB-2 stainless steel autoclave starting from TlNO3 (0.38 mmol; abcr, 99.5%), RhI3 (0.06 mmol; abcr, 99%), and Ba(NO3)2 (0.19 mmol; VEB Laborchemie Apolda, 99%). Water and potassium hydroxide (86%, Fisher Scientific) in the molar ratio of 1.6:1.0 were added to these compounds. The sealed autoclave was heated at a heating rate of 2 K min−1 to 473 K and after 10 h cooled to room temperature at a rate of 0.1 K min−1. The reaction product after washing with water mainly consisted of thallium(I) iodide, thallium(III) oxide, barium carbonate and a brown powder of an unidentified rhodium-containing compound. A few black single crystals of Tl3IO with a needle-like morphology were found, which are sensitive to water and other protic solvents. In contact with water, the Tl3IO crystals immediately turn yellow, probably due to the formation of thallium(I) hydroxide and thallium(I) iodide, which are both yellow. Energy-dispersive on Tl3IO single-crystals revealed a disproportionately high oxygen content, indicating surface decomposition.
Several experiments failed to exchange rhodium(III) iodide with other iodine sources like potassium iodide, copper(I) iodide or silver(I) iodide. Likewise, experiments without barium nitrate were not successful. However, when both starting materials were used, Tl3IO was obtained reproducibly, also at reaction temperatures of 423 K or 523 K. Similarly, the hydrothermal synthesis of Na3[Tl(OH)6] starting from thallium(I) sulfate required heavy metal salts like bismuth nitrate (Giesselbach, 2002). The oxidation of thallium(I) to thallium(III) in this reaction was achieved by oxygen in alkaline solutions (Rich, 2007).
The alkali-metal oxide halides M3XO are reported to be very sensitive to traces of moisture or carbon dioxide due to their highly basic nature (Feldmann & Jansen, 1995b). Remarkably, Tl3IO crystallizes in the presence of water from the hydroflux. In other experiments, we synthesized a water sensitive oxohydroxoferrate (Albrecht et al., 2019) or an oxidation sensitive manganate(V) from hydroflux (Albrecht et al., 2020b). Obviously, the activity of water is dramatically reduced in these aqueous salt melts.
4. Refinement
Crystal data, data collection and structure .
details are summarized in Table 3Supporting information
CCDC reference: 2030857
https://doi.org/10.1107/S2056989020012359/pk2648sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020012359/pk2648Isup2.hkl
Data collection: APEX3 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).Tl3IO | Dx = 8.908 Mg m−3 |
Mr = 756.01 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, P63/mmc | Cell parameters from 8223 reflections |
a = 7.1512 (3) Å | θ = 3.2–46.5° |
c = 6.3639 (3) Å | µ = 90.87 mm−1 |
V = 281.85 (3) Å3 | T = 100 K |
Z = 2 | Needle, black |
F(000) = 608 | 0.09 × 0.05 × 0.03 mm |
Bruker APEXII CCD diffractometer | 442 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.049 |
Absorption correction: multi-scan (SADABS; Bruker, 2016) | θmax = 45.0°, θmin = 3.3° |
Tmin = 0.113, Tmax = 0.749 | h = −14→14 |
15853 measured reflections | k = −11→14 |
480 independent reflections | l = −11→12 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0193P)2] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.018 | (Δ/σ)max < 0.001 |
wR(F2) = 0.041 | Δρmax = 2.80 e Å−3 |
S = 1.29 | Δρmin = −2.01 e Å−3 |
480 reflections | Extinction correction: SHELXL-2016/6 (Sheldrick 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
10 parameters | Extinction coefficient: 0.0035 (2) |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
Tl | 0.16078 (2) | 0.32156 (2) | 0.250000 | 0.00465 (5) | |
I | 0.666667 | 0.333333 | 0.250000 | 0.00534 (7) | |
O | 0.000000 | 0.000000 | 0.000000 | 0.0068 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Tl | 0.00378 (6) | 0.00238 (6) | 0.00733 (9) | 0.00119 (3) | 0.000 | 0.000 |
I | 0.00418 (9) | 0.00418 (9) | 0.00765 (18) | 0.00209 (5) | 0.000 | 0.000 |
O | 0.0068 (10) | 0.0068 (10) | 0.0068 (19) | 0.0034 (5) | 0.000 | 0.000 |
Tl—Tli | 3.4494 (3) | Tl—Tlvi | 3.7538 (1) |
Tl—Tlii | 3.7538 (1) | Tl—Tlvii | 3.7018 (3) |
Tl—Tliii | 3.7538 (1) | Tl—Tlviii | 3.7018 (3) |
Tl—Tliv | 3.4494 (3) | Tl—O | 2.5490 (1) |
Tl—Tlv | 3.7538 (1) | Tl—Oix | 2.5490 (1) |
Tli—Tl—Tliv | 60.0 | O—Tl—Tlviii | 132.580 (2) |
Tliv—Tl—Tliii | 62.648 (2) | Oix—Tl—Tlviii | 132.580 (2) |
Tlvii—Tl—Tlvi | 90.0 | Oix—Tl—Tliv | 47.420 (2) |
Tli—Tl—Tlviii | 180.0 | Oix—Tl—Tli | 47.420 (2) |
Tlv—Tl—Tliii | 115.917 (5) | O—Tl—Tliii | 42.580 (2) |
Tliv—Tl—Tlviii | 120.0 | O—Tl—Tliv | 47.420 (2) |
Tlii—Tl—Tlv | 149.235 (3) | Oix—Tl—Tlvii | 132.580 (2) |
Tli—Tl—Tlvii | 120.0 | O—Tl—Tlvii | 132.580 (2) |
Tliii—Tl—Tlvi | 149.235 (3) | O—Tl—Tli | 47.420 (2) |
Tliv—Tl—Tlvii | 180.0 | O—Tl—Tlv | 108.774 (4) |
Tliv—Tl—Tlvi | 90.0 | O—Tl—Tlii | 42.580 (2) |
Tlviii—Tl—Tlvii | 60.0 | O—Tl—Tlvi | 108.774 (4) |
Tlv—Tl—Tlvi | 54.704 (4) | Oix—Tl—Tlvi | 42.580 (2) |
Tli—Tl—Tlii | 62.648 (2) | Oix—Tl—Tliii | 108.774 (4) |
Tli—Tl—Tliii | 90.0 | O—Tl—Oix | 77.242 (5) |
Tliv—Tl—Tlii | 90.0 | Tlx—O—Tli | 94.839 (4) |
Tlviii—Tl—Tliii | 90.0 | Tlx—O—Tliii | 85.161 (4) |
Tlviii—Tl—Tlii | 117.352 (2) | Tl—O—Tlx | 180.0 |
Tlii—Tl—Tliii | 54.704 (4) | Tliv—O—Tli | 85.161 (4) |
Tlvii—Tl—Tlii | 90.0 | Tl—O—Tlii | 94.840 (4) |
Tli—Tl—Tlvi | 62.648 (2) | Tliv—O—Tliii | 94.839 (4) |
Tli—Tl—Tlv | 90.0 | Tlx—O—Tlii | 85.160 (4) |
Tlviii—Tl—Tlvi | 117.352 (2) | Tlii—O—Tli | 94.839 (4) |
Tliv—Tl—Tlv | 62.648 (2) | Tl—O—Tliv | 85.160 (4) |
Tlii—Tl—Tlvi | 115.917 (5) | Tl—O—Tliii | 94.840 (4) |
Tlviii—Tl—Tlv | 90.0 | Tlx—O—Tliv | 94.840 (4) |
Tlvii—Tl—Tlv | 117.352 (2) | Tlii—O—Tliii | 85.161 (4) |
Tlvii—Tl—Tliii | 117.352 (2) | Tlii—O—Tliv | 180.0 |
Oix—Tl—Tlii | 108.774 (4) | Tli—O—Tliii | 180.0 |
Oix—Tl—Tlv | 42.580 (2) | Tl—O—Tli | 85.160 (4) |
Symmetry codes: (i) −y, x−y, z; (ii) x−y, x, −z; (iii) y, −x+y, −z; (iv) −x+y, −x, z; (v) y, −x+y, −z+1; (vi) x−y, x, −z+1; (vii) −x+y, −x+1, z; (viii) −y+1, x−y+1, z; (ix) −x, −y, z+1/2; (x) −x, −y, −z. |
Atom | Wyckoff symbol | x | y | z | Uiso/Ueq |
Tl | 6h | 0.1608 (1) | 0.3216 (1) | 1/4 | 47 (1) |
I | 2d | 2/3 | 1/3 | 1/4 | 53 (1) |
O | 2a | 0 | 0 | 0 | 68 (7) |
Atom | U11 | U22 | U33 | U23 | U12 | U13 |
Tl | 38 (1) | 24 (1) | 73 (1) | 0 | 0 | 12 (1) |
I | 42 (1) | 42 (1) | 77 (2) | 0 | 0 | 21 (1) |
O | 68 (10) | 68 (10) | 68 (19) | 0 | 0 | 34 (5) |
Funding information
This work was financially supported by the Deutsche Forschungsgemeinschaft (project-id: 438795198).
References
Albrecht, R., Doert, T. & Ruck, M. (2019). ChemistryOpen 8, 1399–1406. Web of Science CrossRef ICSD CAS PubMed Google Scholar
Albrecht, R., Doert, T. & Ruck, M. (2020a). Z. Anorg. Allg. Chem. In the press. https://doi.org/10.1002/zaac.202000031 Google Scholar
Albrecht, R., Doert, T. & Ruck, M. (2020b). Z. Anorg. Allg. Chem. In the press. https://doi.org/10.1002/zaac.202000065. Google Scholar
Babel, D. (1969). Z. Anorg. Allg. Chem. 369, 117–130. CrossRef ICSD CAS Web of Science Google Scholar
Barrett, C. S. (1958). Phys. Rev. 110, 1071–1072. CrossRef ICSD CAS Web of Science Google Scholar
Bruker (2016). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chance, W. M., Bugaris, D. E., Sefat, A. S. & zur Loye, H.-K. (2013). Inorg. Chem. 52, 11723–11733. Web of Science CrossRef CAS PubMed Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Feldmann, C. & Jansen, M. (1995a). Z. Anorg. Allg. Chem. 621, 201–206. CrossRef ICSD CAS Web of Science Google Scholar
Feldmann, C. & Jansen, M. (1995b). Z. Anorg. Allg. Chem. 621, 1907–1912. CrossRef ICSD CAS Web of Science Google Scholar
Feldmann, C. & Jansen, M. (1995c). Z. Naturforsch. Teil B, 50, 1415–1416. CrossRef CAS Google Scholar
Giesselbach, M. (2002). Neue komplexe Hydroxide, Oxidhydroxide und Oxide von schweren Hauptgruppenmetallen. PhD Thesis, Universität Köln, Germany. Google Scholar
Hippler, K., Sitta, S., Vogt, P. & Sabrowsky, H. (1990). Acta Cryst. C46, 736–738. CrossRef ICSD CAS Web of Science IUCr Journals Google Scholar
Rich, R. (2007). Inorganic Reactions in Water, p. 321. Berlin Heidelberg: Springer-Verlag. Google Scholar
Sabrowsky, H. (1971). Z. Anorg. Allg. Chem. 381, 266–279. CrossRef ICSD CAS Web of Science Google Scholar
Sabrowsky, H., Feldbaum-Möller, E., Fischer, K., Sitta, S., Vogt, P. & Winter, V. (1996). Z. Anorg. Allg. Chem. 622, 153–156. CrossRef ICSD CAS Web of Science Google Scholar
Sabrowsky, H., Paszkowski, K., Reddig, D. & Vogt, P. (1988). Z. Naturforsch. Teil B, 43, 238–239. CrossRef CAS Google Scholar
Shannon, R. D. (1976). Acta Cryst. A32, 751–767. CrossRef CAS IUCr Journals Web of Science Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sitta, S., Hippler, K., Vogt, P. & Sabrowsky, H. (1991a). Z. Anorg. Allg. Chem. 597, 197–200. CrossRef ICSD CAS Web of Science Google Scholar
Sitta, S., Hippler, K., Vogt, P. & Sabrowsky, H. (1991b). Z. Kristallogr. 196, 193–196. CrossRef ICSD CAS Web of Science Google Scholar
Wortmann, R., Sitta, S. & Sabrowsky, H. (1989). Z. Naturforsch. Teil B, 44, 1348–1350. CrossRef ICSD CAS Google Scholar
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