Beiträge zum thermischen Verhalten und zur Kristallchemie wasserfreier Phosphate. XXXIX

Contributions on the Thermal Behaviour and Crystal Chemistry of Anhydrous Phosphates. XXXIX, Syntheses, Crystal Structures and Structural Systematics of Quaternary Vanadium(IV) Oxidephosphates M II V 2 O 2 (PO 4 ) 2 ( M II : Co, Ni, Cu) By vapour‐phase assisted solid state reactions single‐crystals of the oxidephosphates α‐CoV 2 O 2 (PO 4 ) 2 (green), β ‐NiV 2 O 2 (PO 4 ) 2 (yellow), and CuV 2 O 2 (PO 4 ) 2 (brown) suitable for structural investigations were grown ( α‐CoV 2 O 2 (PO 4 ) 2 : P 2 1 / c , Z = 2, a = 6.310(1), b = 7.275(1), c = 7.441(2) Å, β = 90.30(2)°, R 1 = 0.044, w R 2 = 0.083, 1515 independent reflections, 71 variables; β ‐NiV 2 O 2 (PO 4 ) 2 : P 2 1 / c , Z = 2, a = 7.4013, b = 7.2595, c = 7.4230Å, β = 121.56°, R 1 = 0.037, w R 2 = 0.084, 1117 independent reflections, 61 variables; CuV 2 O 2 (PO 4 ) 2 : Pbca , Z = 8, a = 7.352(1), b = 12.652(1), c = 14.504(2) Å, R 1 = 0.048, w R 2 = 0.067, 2886 independent reflections, 136 variables). β ‐CoV 2 O 2 (PO 4 ) 2 and α‐NiV 2 O 2 (PO 4 ) 2 were obtained as powders only. The α‐forms belong to the α‐Fe 2 O(PO 4 ) structure family, while the β ‐forms are isotypic to NiTi 2 O 2 (PO 4 ) 2 (Lipscombite/Lazulite structure family). The oxidephosphate structures are characterized by three‐dimensional networks of [PO 4 ] tetrahedra and [ M V 2 O 12 ] groups formed by face‐sharing of [ M II O 6 ] and [V IV O 6 ] octahedra.