Structure determination of Cs0.864Rb1.136SeO4 |
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Authors: | Jan Fábry Václav Petřiček Marta Šimečková Přemysl Vaněk |
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Institution: | 1. Inst. of Physics Czech Acad. Sci , Cukrovarnická 10, 162 00, Praha 6, Czech Republic;2. Inst. of Physics Czech Acad. Sci , Na Slovance 2, 180 40 Praha 8, Czech Republic |
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Abstract: | The present structure determination of Cs x Rb2-x SeO4 shows that the crystal belongs to the β - K2SO4 family, like the related compounds Cs2SeO4 and Rb2SeO4. In β - K2SO4 compounds the cations occupy two different sites; one of these sites, which is surrounded by 11 anionic atoms, is occupied preferentially by Cs, while the other one with 9 neighbours by Rb. A slight excess of Rb has been determined by X-ray structure analysis in a single crystal prepared at 292 K; its formula is Cs0.864(9)Rb1.136(9)SeO4. Crystals were grown by evaporation from equimolar water solutions of Cs2SeO4 and Rb2SeO4 at 292 and 301 K. No phase transition was detected by DSC in the range 103-323 K for either of the samples. Lattice parameters of different crystals isolated at various stages of crystallization indicate formation of crystals with a different proportion of Cs/Rb cations. The lattice parameters as well as their ratios differed significantly from those given by Endo et al., (1983). |
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Keywords: | Phase transitions β - K2SO4 compounds structure determination of Cs0 864Rb1 136SeO4 |
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