The synthesis and structure of Ca2InN, a novel ternary indium nitride

Dark red metallic-looking needles of Ca2InN were synthesized in sealed niobium tubes from the elements in molten sodium with sodium azide as the nitrogen source. It crystallizes in the orthorhombic space group Cmcm (No.63), cell parameters a = 3.532(3) b = 20.204(16) Angstrom, c = 4.969(4) Angstrom and is isotypic to Ca2AuN. It is characterized by one dimensional zig-zag chains of indium and planes of Ca6N edge sharing octahedra. Extended Huckel calculations show the intra-chain bonding to be much more significant than the inter-chain interactions. Significant mixing of Ca and In orbitals leads to important interactions between the chains and the calcium nitride layers. (C) 2002 Elsevier Science B.V. All rights reserved.