Crystal structure and spectroscopic properties of AVO2SO4 (A = K, Rb) compounds

The crystal structure of alkali-metal dioxovanadium(V) sulfates AVO2SO4, where A is K or Rb, has been determined based on a combination of neutron and X-ray diffraction data. The compounds are isostructural and have an orthorhombic lattice (space group P212121, Z = 4) with unit cell parameters a = 11.1004(2) and 10.8193(1) A; b = 8.2626(2) and 8.9042(1) A; c = 5.4772(1) and 5.5722(1) A, respectively. The structures are of the chain type. Zigzag chains are formed by vertex-sharing VO6 octahedra. Sulfate groups SO4 link neighboring chains and form a spatial framework with cavities accommodating alkali-metal atoms with CN = 9 (K) and 8 (Rb). IR and Raman spectroscopy data are reported.