New hexachalcogeno-hypodiphosphates of the alkali metals: Synthesis, crystal structure and vibrational spectra of the hexathiodiphosphate(IV) hydrates K-4[P2S6] center dot 4 H2O, Rb-4[P2S6] center dot 6 H2O, and Cs-4[P2S6] center dot 6 H2O

摘要

The new hexathiodiphosphate(IV) hydrates K-4[p(2)S(6)] (.) 4 H2O (1), Rb-4[P2SI] (.) 6 H2O (2), and CS4[P2S6] (.) 6 H2O (3) were synthesized by soft chemistry reactions from aqueous solutions of Na-4[P2S6] (.) 6 H2O and the corresponding heavy alkali-metal hydroxides. Their crystal structures were determined by single crystal Xray diffraction. K-4[P2S6] (.) 4 H2O (1) crystallizes in the monoclinic space group P2(1) with a 803.7(1), b = 1129.2(1), c = 896.6(1) pm, beta = 94.09(1)degrees, Z = 2. Rb-4[P2S6] (.) 6 H2O (2) crystallizes in the monoclinic space group P2(1)/c with a = 909.4(2), b = 1276.6(2), c = 914.9(2) pm, beta = 114.34(2)degrees, Z = 2. CS4[P2S6] (.) 6 H2O (3) crystallizes in the triclinic space group P 1 with a = 742.9(2), b = 929.8(2), c = 936.8(2) pm, alpha = 95.65(2), beta = 112.87(2), gamma = 112.77(2)', Z = 1. The structures are built up by discrete [P2S6](4-) anions in staggered conformation, the corresponding alkali-metal cations and water molecules. O (...) S and O (...) O hydrogen bonds between the [P2S6](4-) anions and the water molecules consolidate the structures into a three-dimensional network. The different water-content compositions result by the corresponding alkali-metal coordination polyhedra and by the prefered number of water molecules in their coordination sphere, respectively The FT-Raman and FT-IR/FIR spectra of the title compounds have been recorded and interpreted, especially with respect to the [P2S6](4-) group. The thermogravimetric analysis showed that K-4[P2S6] (.) 4 H2O converted to K-4[P2S6] as it was heated at 100 degrees C.