Quantum-chemical analysis of the chemical stability and cohesive properties of hexagonal TiB2, VB2, ZrB2 and NbB2

The cohesive properties and chemical stability of diborides MB₂ have been analysed using the results of full-potential LMTO calculations. A comparison of interatomic M–M, M–B and B–B interactions in MB₂ phases (M = Ti, V, Zr, Nb) shows that the changes in the cohesive properties are mainly controlled by the strength of the covalent M–B bonds.