Ba[CoN]: Ein niedervalentes Nitridocobaltat mit gewinkelten Ketten [CoN2/22−]

BaCoN]: A Low-Valency Nitridocobaltate with Angled Chains CoN_2/2^2?] BaCoN] is prepared by reaction of barium and cobalt (molar ratio Ba : Co = 1 : 2.5) in tantalum crucibles at 870°C with flowing nitrogen (1 atm) within a period of 96 h. After cooling down to room temperature (24°C/h) black single crystals of the ternary phase with a platy habit are obtained (orthorhombic, Pnma; a = 959.9(2) pm, b = 2 351.0(3) pm, c = 547.6(2) pm; Z = 20). The crystal structure of BaCoN] contains angled (planar) chains CoN_2/2^2?] which run along the 010]-direction (N? Co? N°]: 178.5(5), 179.6(6), 180.0; Co? N? Co°]: 82.9(6), 84.2(5), 177.1(8); Co? Npm]: 174.6(12), 177.2(12), 181.9(13), 184.3(13), 187.1(12)). Nitrogen is in an octahedral coordination (N Ba₄Co₂) and is arranged in a distorted cubic close packing. Barium occupies one half of the tetrahedral holes (Ba? Npm]: 274.8(16) ? 308.2(12)). The cis-positions of the Co-atoms at the nitrogen coordination-octahedra cause short Co? Co contacts within the chains CoN_2/2^2?]. Through this, Co₂-units (Co? Copm]: 247.8(4); bridged by nitrogen) and linear Co₃-groups (Co? Co pm]: 245.5(2); Co? Co? Co°]: 180.0; bridged by nitrogen) alternate along the chains. The crystal structure of BaCoN] is closely related to the BaNiN] type structure.