Nitridocuprate(I): Quaternäre Phasen in den Systemen Li—Ca/Sr—Cu—N / Nitridocuprates(I): Quaternary Phases in the Systems Li—Ca/Sr—Cu—N

Abstract

The crystal structures of the intermediate phases in the quaternary systems Li–Ca/Sr–Cu–N are characterized by structural units containing substitutional positions (Li1-xCux) in two-fold and linear coordination by nitrogen. The bond-lengths (Li1-xCu1-x)–N are shortened with increasing Cu-content. SrLi2[(Li1-xCux)N]2: Isotype of Li4SrN2; 0 ≦ x ≦ 0.39 (I 41/amd; Z = 4; x = 0.39: a = 377.0(1) pm, c = 2736.8(6) pm). (Li0.61Cu0.39)–N: 188.5(3) pm. Sr[(Li1-xCux)N]: Isotype of Ba[NiN]; 0.33 ≦ x ≦ 0.52 (Pnma; Z = 12; x = 0.52: a = 900.1(3) pm, b = 1315.1(5) pm, c = 546.4(1) pm). (Li0.42Cu0.58)–N: 189.0(13) pm. Ca2{(Li1-xCux)(a)[(Li1-xCux)(b)N2]}: Isotype of Sr2{Li[CoN2]}; 0.03 ≦ x(a) ≦ 0.27, 0.72 ≦ x(b) ≦ 0.80 (P42/mnm; Z = 2; x(a) = 0.27/x(b) = 0.80: a = 529.3(1) pm, c = 663.1(2) pm). (Li0.73Cu0.27)(a)—N: 188.0(7) pm; (Li0.20Cu0.80)(b)–N: 186.2(7) pm. Based on the experimental results the bond-length CuI–N of two-fold (linear) coordinated Cu(I) in nitrido-compounds is estimated to be 184.5(5) pm.