Answers are grounded in this paper and cite their sources.
Microhardness of single crystals of V3Si and V3Ge as well as polycrystalline Nb3Ir, Nb3Au, and Nb3Sn have been measured. The relatively high ratio of hardness to elastic constant C44 supports the existence of strong covalency in A3B compounds of the A15 structure. Correlation with interatomic distance suggests covalent bonding (tight binding) in the A-A chains.
No takes yet. Share an insight, caveat, or question.
Chin et al. (1978) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: