Electronic structure of ZrNi sub(4)P sub(2) and related compounds with ZrFe sub(4)Si sub(2)-type structure

Extended Huckel molecular orbital and tight-binding band structure calculations have been performed on ZrNi sub(4)P sub(2) and then applied through a rigid band model to related compounds with the same ZrFe sub(4)Si sub(2)-type structure. The electronic structure has been built up step by step, from fragments, in order to obtain a better understanding of the main interactions which govern the evolution of the lengths of the metal-metal bonds and the lattice cohesion. The role of the 3d metal electron count and that of the ligand matrix are displayed and discussed. The bonding character between the zirconium cation and the covalent system !NI sub(4)P sub(2)! is also studied in some detail.