Structure cristalline du monophosphate lacunaire K Ti2 (PO4)3. Monophosphates lacunaires Nb Ge (PO4)3 et M+5Ti (PO4)3 pour M+5 = Sb, Nb, Ta

Abstract

A new phase of potassium titanium monophosphate KTi₂ (PO₄)₃ was prepared. This form is cubic with a = 9.77 Å, space group : P2₂3 and is isotypic with langbeinite. The substitution of K⁺ and Ti⁺⁴ by M⁺⁵ = Sb, Nb, Ta in the rhombohedral form of KTi₂ (PO₄)₃ leads to isotypic compounds : M⁺⁵Ti⁺⁴ KTi₂ (PO₄)₃.