Electronic Structure of a New Ternary Chalcogenide: NbNiTe5

An attempt at analyzing the electronic structure and bonding in the metallic and paramagnetic compound NbNiTes has been made, using extended Huckel tight-binding calculations. The metallic behavior of this compound originates primarily from Te 5p states. Rather anisotropic conductivity is expected. It is difficult to>assign a definitive oxidation state to the elements in this compound, but we suggest that an oxidation formalism of (Nb3+)(Ni2+)(Te)(5)(5-) may be appropriate. This accounts for the numerous Te-Te contacts and electronegativity considerations but not for the magnetic measurements. The bonding between tellurium and transition-metal atoms is highly covalent; the compound can be considered as an intermetallic phase. The title compound and its Ta and Pd derivatives are compared, as well as some layerlike rare-earth-metal tellurides.