Zum Mineral Johillerit verwandte Oxovanadate RbCd4V3O12 und TlCd4V3O12 / Oxovanadates RbCd4V3O12 and TlCd4V3 O12 Related to the Mineral Johillerite

Single crystals of I RbCd₄V₃O₁₂ and TlCd₄V₃O₁₂ II have been prepared by solid state reactions in closed iron tubes. The compounds crystallize closely related to the Johillerite structure in the space group C⁶₂ₕ- C2/c with I: a = 13.058(3); b - 13.528(3), c = 7 .0 6 0 (2)A , β = 114.88(2)°; II: a = 12.999(6), b = 13.527(7), c = 7.055(3) A , β = 114.88(4)°, Z = 4. Special features are the loss of Cu²⁺ in order to gain an additional Cd²⁺ position. The crystal structure is discussed with respect to related compounds of the Johillerite type.