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

Colourless single crystals of KBaPS (a = 11.587(2), b = 6.700(1), c = 10.118(2) Å ), and pale orange ones of KBaPSe (a = 11.972(2), b = 6.973(1), c = 10.388(2) Å ) were obtained by reactions of Ba (PS and Ba (PSe , respectively, with KCl (790 °C; 30 h). The isotypic compounds crystallize with a slightly modified TlEuPS type structure (Pnma, Z = 4); that is, the characteristic units are distorted discrete PX tetrahedra (X: S, Se) interconnected by K and Ba . However, due to the strong distortion of the trigonal X 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 Ba PO PSe (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 Ba (PSe . The compound crystallizes in a new type of structure (P1̅; Z = 2) and is the first chalcogenophosphate with discrete PO and PSe tetrahedra. The coordination polyhedra of the barium atoms are formed by both chalcogen atoms