Chains of [RE6] Octahedra Coupled by (NCN) Links in the Network Structure of RE2Cl(CN2)N. Synthesis and Structure of Two Novel Rare Earth Chloride Carbodiimide Nitrides with Structures Related to the RE2Cl3 Type

• Published in: Inorganic chemistry 2003-06, Vol.42 (11), p.3406-3411
• Main Authors: Srinivasan, Radhakrishnan, Ströbele, Markus, Meyer, H.-Jürgen
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic020685z

Solid state metathesis reactions between RECl3 (RE = La, Ce) and Li2CN2 at 800 °C have led to the discovery of the rare earth chloride carbodiimide nitrides La2Cl(CN2)N (1) and Ce2Cl(CN2)N (2), respectively. Single crystal X-ray diffraction analyses revealed that 1 and 2 crystallize isotypic in an orthorhombic system (Cmmm, Z = 4, a = 13.3914(8) Å, b = 9.6345(7) Å, c = 3.9568(2) Å for 1 and a = 13.340(1) Å, b = 9.5267(8) Å, c = 3.9402(5) Å for 2). The crystal structures of 1 and 2 contain linear chains of edge-sharing octahedra built from rare earth metal atoms. Similar to [M6X8] type clusters, the [RE6] octahedra are capped by eight nitrogen atoms above their faces, of which four are from N3- ions and the other four are from (CN2)2- ions. The chains are interconnected by bridging (CN2)2- to form a three-dimensional network with Cl- ions in linear channels. Compounds 1 and 2 are surprisingly stable toward air and water. They have been characterized by thermal analysis, infrared spectroscopy, and magnetic susceptibility studies.