Neue Chalcogenophosphate: KBaPS4, KBaPSe4 und Ba3PO4PSe4 New Chalcogenophosphates: KBaPS4, KBaPSe4, and Ba3PO4PSe4

Colourless single crystals of KBaPS4 (a = 11.587(2), b = 6.700(1), c = 10.118(2) Å), and pale orange ones of KBaPSe4 (a = 11.972(2), b = 6.973(1), c = 10.388(2) Å) were obtained by reactions of Ba3(PS4)2 and Ba3(PSe4)2, respectively, with KCl (790 ◦C; 30 h). The isotypic compounds crystallize with a slightly modified TlEuPS4 type structure (Pnma, Z = 4); that is, the characteristic units are distorted discrete PX4 tetrahedra (X : S, Se) interconnected by K+ and Ba2+. However, due to the strong distortion of the trigonal X6 prisms along [001] the coordination numbers increase from 8 to 9 for the barium atoms and from 8 to 11 for the potassium atoms. Orange crystals of Ba3PO4PSe4 (a = 6.779(1), b = 7.108(1), c = 12.727(3) Å; α = 82.45(3)◦, β = 78.88(3)◦ , γ = 81.34(3)◦) resulted as a by-product of the synthesis of Ba3(PSe4)2. The compound crystallizes in a new type of structure (P1̄; Z = 2) and is the first chalcogenophosphate with discrete PO4 and PSe4 tetrahedra. The coordination polyhedra of the barium atoms are formed by both chalcogen atoms.