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Twinned Caesium Cerium(IV) Pentafluoride Table 1 Selected Bond Lengths (A˚ )

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Twinned Caesium Cerium(IV) Pentafluoride Table 1 Selected Bond Lengths (A˚ ) inorganic compounds Acta Crystallographica Section E Structure Reports Refinement Online R[F 2 >2(F 2)] = 0.037 129 parameters 2 ˚ À3 ISSN 1600-5368 wR(F ) = 0.038 Ámax = 1.85 e A ˚ À3 S = 1.04 Ámin = À1.89 e A 6402 reflections Twinned caesium cerium(IV) pentafluoride Table 1 Selected bond lengths (A˚ ). a b Andrzej Grzechnik, * Christopher C. Underwood and Ce1—F3 2.133 (6) Cs1—F1iv 2.928 (8) Joseph W. Kolisb Ce1—F4 2.304 (5) Cs1—F2 3.152 (6) Ce1—F5 2.256 (6) Cs1—F2v 2.982 (6) i vi a Ce1—F5 2.311 (6) Cs1—F3 3.222 (7) Institute of Crystallography, RWTH Aachen University, Ja¨gerstr. 17-19, 52066 Ce1—F6 2.320 (5) Cs1—F3iii 3.229 (7) b Aachen, Germany, and Department of Chemistry, Clemson University, Clemson SC Ce1—F7 2.306 (6) Cs1—F5vi 3.099 (6) 29634, USA Ce1—F8 2.119 (7) Cs1—F8 3.095 (6) Correspondence e-mail: [email protected] Ce1—F9 2.487 (6) Cs1—F8vii 3.218 (6) Ce1—F9i 2.882 (7) Cs1—F9 2.982 (5) vi Received 28 January 2014; accepted 13 February 2014 Ce2—F1 2.123 (7) Cs2—F1 2.998 (6) Ce2—F2 2.128 (7) Cs2—F1viii 2.998 (7) Ce2—F4ii 2.329 (5) Cs2—F2ix 3.042 (8) Ce2—F6 2.395 (6) Cs2—F3vi 3.437 (6) Key indicators: single-crystal X-ray study; T = 295 K; mean (Ce–F) = 0.006 A˚; Ce2—F6iii 3.150 (7) Cs2—F3iii 2.981 (6) iii vi R factor = 0.037; wR factor = 0.038; data-to-parameter ratio = 49.6. Ce2—F7 2.322 (6) Cs2—F6 3.125 (6) Ce2—F9 2.304 (6) Cs2—F7vii 3.140 (6) Ce2—F10 2.242 (5) Cs2—F8 2.980 (7) Ce2—F10i 2.279 (6) Cs2—F10viii 3.162 (6) Single-crystals of CsCeF5 were synthesized hydrothermally. 3 1 3 1 3 1 Symmetry codes: (i) x; Ày þ 2; z À 2; (ii) x þ 1; Ày þ 2; z þ 2; (iii) x; Ày þ 2; z þ 2; (iv) The crystal under investigation was twinned by pseudo- 1 1 1 1 Àx þ 2; y À 2; Àz þ 2; (v) Àx þ 2; Ày þ 1; Àz þ 1; (vi) Àx þ 1; y À 2; Àz þ 2; (vii) c 3 1 merohedry with a twofold rotation around the axis as an Àx þ 1; Ày þ 1; Àz; (viii) x À 1; Ày þ 2; z À 2; (ix) x À 1; y; z. additional twinning operation. The crystal structure is built of layers of distorted edge- and corner-sharing CeF8 square- Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X- antiprisms. The Cs+ cations are located between the layers and AREA; data reduction: X-AREA; program(s) used to solve structure: exhibit coordination numbers of nine. Upon compression, SIR97 (Altomare et al., 1999); program(s) used to refine structure: JANA2006 (Petrˇı´cˇek et al., 2006); molecular graphics: DIAMOND CsCeF5 undergoes an irreversible phase transition at about 1 GPa. (Brandenburg, 2000); software used to prepare material for publi- cation: publCIF (Westrip, 2010). Related literature We thank Karen Friese for discussions. We also acknowl- For background to the applications of complex cerium(IV) edge the National Science Foundation grant No. DMR- and thorium fluorides, see: Friese et al. (2011); Grzechnik et al. 0907359 for financial support. (2007, 2008, 2013a,b); Rouse & Weller (2009); Underwood (2013); Underwood et al. (2012). For related structures, see: Supporting information for this paper is available from the IUCr Underwood et al. (2012). The ruby luminescence method electronic archives (Reference: FJ2660). (Mao et al., 1986) was used for pressure calibration. According to a recent review of twinning at high pressures (Friese & References Grzechnik, 2014), pseudo-merohedral twinning in general is not significantly affected on compression. Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Brandenburg, K. (2000). DIAMOND. Crystal Impact GbR, Bonn, Germany. Experimental Friese, K. & Grzechnik, A. (2014). Z. Kristallogr. DOI: 10.1515/zkri-2013-1662. Friese, K., Morgenroth, W., Posse, J. M. & Grzechnik, A. (2011). Dalton Trans. Crystal data 40, 1902–1910. ˚ 3 CsCeF5 V = 968.39 (9) A Grzechnik, A., Fechtelkord, M., Morgenroth, W., Posse, J. M. & Friese, K. Mr = 368 Z =8 (2007). J. Phys. Condens. Matter, 19, 266219 (11pp). J. Solid State Chem. Monoclinic, P21=c Mo K radiation Grzechnik, A., Morgenroth, W. & Friese, K. (2008). 181, a = 8.3125 (5) A˚ = 16.80 mmÀ1 971–975. b = 14.2434 (6) A˚ T = 295 K Grzechnik, A., Underwood, C. C., Kolis, J. W. & Friese, K. (2013a). J. Fluor. c = 8.4507 (5) A˚ 0.10 Â 0.08 Â 0.05 mm Chem. 150, 8–13. = 104.566 (5) Grzechnik, A., Underwood, C. C., Kolis, J. W. & Friese, K. (2013b). J. Fluor. Chem. 156, 124–129. Mao, H. K., Xu, J. & Bell, P. M. (1986). J. Geophys. Res. 91, 4673–4676. Data collection Petrˇı´cˇek, V., Dusˇek, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, STOE IPDS 2 diffractometer 55729 measured reflections Praha, Czech Republic. Absorption correction: numerical 6402 independent reflections Rouse, J. & Weller, M. T. (2009). Dalton Trans. 38, 10330–10337. (X-SHAPE; Stoe & Cie, 2002) 2543 reflections with I >3(I) Stoe & Cie (2002). X-AREA and X-SHAPE. Stoe & Cie, Darmstadt, Tmin = 0.207, Tmax = 0.406 Rint = 0.136 Germany. i12 Grzechnik et al. doi:10.1107/S1600536814003286 Acta Cryst. (2014). E70, i12–i13 inorganic compounds Underwood, C. C. (2013). PhD Thesis, Hydrothermal Chemistry, Crystal Underwood, C. C., Mann, M., McMillen, C. D., Musgraves, J. D. & Kolis, J. W. Structures, and Spectroscopy of Novel Fluorides and Borates, Clemson (2012). Solid State Sci. 14, 574–579. University, USA. Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Acta Cryst. (2014). E70, i12–i13 Grzechnik et al. CsCeF5 i13 supporting information supporting information Acta Cryst. (2014). E70, i12–i13 [doi:10.1107/S1600536814003286] Twinned caesium cerium(IV) pentafluoride Andrzej Grzechnik, Christopher C. Underwood and Joseph W. Kolis S1. Introduction Most of the work on structural inorganic chemistry of actinide fluorides has been primarily based on the materials that crystallize from molten alkali fluoride salts (Grzechnik et al., 2007; Grzechnik et al., 2008; Friese et al., 2011). Recently, several complex thorium fluorides have been synthesized (Underwood et al., 2012; Grzechnik et al., 2013a) and advances in the synthesis of cerium (IV) fluorides have been made (Rouse et al., 2009; Grzechnik et al., 2013b). The successful use of fluoride mineralizers in the hydrothermal crystal growth of alkali thorium fluorides suggests that additional investigations into inorganic cerium (IV) fluorides may be fruitful. The chemistry of monovalent metal cerium(IV) fluorides in hydrothermal fluids was examined by Underwood (2013) and it was found that it is considerably richer than anticipated. We are interested in the crystal structures and stabilities of cerium (IV) fluorides as they are thought to be isostructural with the actinide fluorides (Grzechnik et al., 2013b). In the recent study by Underwood et al. (2012), three new polymorphs of CsThF5 have been synthesized hydrothermally. The tetragonal phase (phase I, P4/nmm, Z = 2), consisting of sheets of ThF9 tricapped trigonal prisms separated by layers of Cs atoms, is a minor product in the hydrothermal conditions. Two monoclinic polymorphs (phases II and III) are synthesized at various conditions. The phase II (P21/c, Z = 4) is built of chains of corner-sharing ThF9 polyhedra, while the phase III (P21/c, Z = 8) is built of sheets of edge- and corner-sharing ThF9 polyhedra. The chain structure of the phase II converts into the sheet structure of the phase III at 500°C. In this study, we examine cesium cerium(IV) pentafluoride, CsCeF5, to see whether it is indeed isostructural with CsThF5. S2. Experimental A series of crystals mounted on glass pins was tested on a STOE IPDS 2 diffractometer and the best one was selected for the structure determination at ambient conditions and high-pressure single-crystal x-ray studies. High-pressure data were collected in the Ahsbahs-type diamond anvil cell at room temperature at 1.2, 3.1, and 5.0 GPa. A 0.250 mm hole was drilled into a stainless steel gasket preindented to a thickness of about 0.120 mm. A 4:1 mixture of methanol and ethanol was used as a pressure medium. The ruby luminescence method (Mao et al., 1986) was used for pressure calibration. The intensities were indexed and integrated with the software X-AREA (Stoe & Cie, 2002). Due to the pseudomerohedral twinning, some reflections in the lower θ range partly overlap. During the integration the orientation matrices of both twin individuals were used simultaneously. The overlap tolerance was set to 100%, so that all overlapped reflections were included. The faces of the crystal were optimized for each individual with the program X-SHAPE (Stoe & Cie, 2002) and an absorption correction was applied with the program Jana2006 (Petříček et al., 2006). Figures 1-3 were drawn using the program DIAMOND (Brandenburg, 2000). Acta Cryst. (2014). E70, i12–i13 sup-1 supporting information S2.1. Synthesis and crystallization All reagents for the synthesis of CsCeF5 were of analytical grade and used as purchased. The compound in this study was prepared hydrothermally as follows: 0.20 g CeF4 (Strem Chemical, 99.9%) was combined with five molar equivalents (0.703 g) of CsF (Alfa Aesar, 99.9%), placed into a Parr Instruments Teflon-lined autoclave and filled with 10.0 mL water.
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