Crystal structure, vibrational spectrum and thermal behavior of the ammonium hexathiohypodiphosphate dihydrate, (NH4)4P 2S6·2 H2O

Abstract

Single crystals of (NH4)4P2S 6·2H2O could be obtained and the crystal structure determined (monoclinic, P21/c with a = 6.931(1), b = 12.730(2), c = 17.446(2) Å, β = 96.87(1)°, V = 1528.2(4) Å3, Z = 4). The NH4+, and [P2S6] 4- ions and the water molecules are involved in an extended hydrogen-bonding network. The FT-Raman and FT-IR spectra have been recorded and the observed vibrational frequencies assigned to tetrahedral NH4+ and [P2S6]4- (D3d) ions as well as to H2O molecules. The thermogravimetric analysis has shown that (NH4)4P2S6·2 H2O starts to decompose at around 60°C (up to 170°C), but no distinct intermediates could be observed. © 2007 Verlag der Zeitschrift für Naturforschung.