Rb2P2S6 – A New Alkali Thiophosphate: Crystal Structure and Vibrational Spectra of Rubidium Hexathiodiphosphate(V)

Single crystals of rubidium hexathiodiphosphate(V), Rb2P2S6, have been obtained and investigated by single crystal X-ray diffraction, and IR/FIR and Raman spectroscopy. The title compound crystallizes isotypically to the potassium, caesium and thallium analogues in the orthorhombic space group Immm (no. 71) with a = 8.485(3), b= 6.953(3), c =9.259(3 Å , and Z = 2, final R1= 0.0579 and wR2 = 0.0987. The crystal structure is characterized by discrete [P2S6]2− anions (edge-sharing double-tetrahedra) with D2h symmetry. Rubidium is coordinated by ten sulfur atoms forming a slightly distorted two-capped tetragonal prism with a coordination number CNRb 10. The FT-Raman and FT-IR/FIR spectra have been recorded and a factor group analysis was carried out.