Valence electron structure analysis of property differences between MoO₂ and NiMo compounds

Valence electron structures of NiMo and MoO₂ compounds in a MoO₂-strengthened γ/NiMo alloy were analyzed by a bond length difference method on the basis of Yu's Empirical electron theory of solids and molecules. Relationships between hardness, strength and melting point differences of the two compounds and their respective valence electron structure were investigated. The differences were confirmed by measurement results. The ratio of total covalent electron number to valence electron number on all of the bonds in valence electron structures could be used to compare strength of NiMo and MoO₂. Length of the strongest bond in the valence electron structure could be used to measure melting point of NiMo and MoO₂. However, covalent electron pair number of the strongest bond in the valence electron structure could not be viewed as the sole standard for comparing hardness of the two compounds.