Inorganic Chemistry, Vol.40, No.2, 272-276, 2001
Hydrothermal synthesis, thermal, and magnetic data on new alkaline vanadium phosphsate M-y(VO)(9+x)(PO4)(4x)(HPO4)(12-4x) with M = Cs+ (y=5.29, x=1) and M = NH4+, Rb+ (y similar to 5, x similar to 1)
Brownish platelet crystals of M-y(VO)(9+x)(PO4)(4x)(HPO4)(12-4x) (M = Cs+, NH4+ and Rb+) were prepared hydrothermally. The structure of Cs-similar to5(VO)(10)(PO4)(4)(HPO4)(8) was solved from single-crystal X-ray diffraction data in the centrosymmetric monoclinic space group C2/c (No. 15) a = 21.1951(8) Angstrom, b = 12.2051(4) Angstrom, c = 20.6230(8) Angstrom, beta = 109.742(2)degrees, Z = 4 (R-l(Fo) = 0.054, wR(2)(Fo(2)) = 0.123). The structure of Cs-similar to5(VO)(10)(PO4)(4)(HPO4)(8) is described and compared to that of K-2(VO)(3)(HPO4)(4) previously reported by Lii. For the three compounds, thermogravimetric data and susceptibility measurements were investigated and were found to be in agreement with the structural study.