A NEW SAMARIUM NITRIDE SULFIDE - SM4N2S3

The oxidation of samarium with sulfur in the presence of SmCl3 and NaN3 as nitrogen source (molar ratio: 12:9:4:2, evacuated silica vessel, some NaCl as flux, 850 degrees C, 7 d) yields Sm4N2S3 as lath-shaped, dark red single crystals. The by-products (NaCl and NaSm2Cl6 are rinsed with water from the crude product. The crystal structure of Sm4N2S3 (monoclinic, C2/m (no. 12), Z = 2, a = 1318.04(12), b = 391.57(2), c = 1031.76(9) pm, beta = 130.874(6)degrees, R = 0.036, R(w) = 0.031) contains two crystallographically different Sm3+, both in sixfold coordination of the anions. Besides distorted octahedra [(Sm1)N3S3] and [(Sm2)NS5], tetrahedra [(N3-)(Sm3+)(4)] connected via two cis-oriented edges to form chains (1)(i)nfinity[N(Sm1)(3/3)(Sm2)(1/1)](3+) build up the main structural feature. These are arranged in the fashion of a closest packing of rods and held together by two crystallographically different S2- anions which take care for charge neutrality and three-dimensional interconnection.