Die Kristallstrukturen der isotypen Verbindungen Ba₃[MoN₄] und Ba₃[WN₄] / The Crystal Structures of the Isotypic Compounds Ba₃[MoN₄] and Ba₃[WN₄]

The isotypic ternary compounds Ba 3 [MoN 4 ] and Ba 3 [WN 4 ] were prepared by reaction of the transition metals with barium (Ba 3 N 2 , resp.) under nitrogen. The crystal structures were determined by single crystal X-ray diffraction: Ba 3 [MoN 4 ] (Ba 3 [WN 4 ]): Pbca; Z = 8; a = 1083.9(3) pm (1091.8(3) pm), b = 1030.3(3) pm (1037.5(3) pm), c = 1202.9(3) pm (1209.2(4) pm). The structures contain isolated tetrahedral anions [MN 4 ] 6- (M = Mo, W) which are arranged in form of slightly distorted hexagonal layers and which are stacked along [010] with the sequence (···AB···). Two of the three Ba atoms are situated between, the third one is placed within the layers of [MN 4 ]-groups. In this way the structures can be derived from the Na 3 As structure type.