Theoretical study on metal-oxygen bonds in vanadate anions <?A3B2 pi6?> [V <italic> <sub>n</sub> </italic>O<italic> <sub>m</sub> </

Polyoxovanadates (POVs) are widely used in various fields, making it crucial to understand the electronic properties for their optimal applications. In this study, the electronic structures of fully-oxidized vanadate anions [V<italic> _n </italic>O<italic> _m </italic>]^3‒/4‒(<italic>n</italic> = 1 – 5, <italic>m</italic> = 4, 7, 9, 12, 14), including [VO₄]^3‒, [V₂O₇]^4‒, [V₃O₉]^3‒, [V₄O₁₂]^4‒, and [V₅O₁₄]^3‒, were investigated using density functional theory (DFT) calculations. A comprehensive analysis was conducted on the bond lengths, Wiberg bond index (WBI), bond critical points (BCPs), and covalent composition of these vanadates. The interaction between V―O_t and V―O_b in studied [V<italic> _n </italic>O<italic> _m </italic>]^3‒/4‒can be viewed as the combination of covalent bond and ionic bond. With an increase in the number of vanadium atoms, the V―O bond lengths decrease, while the covalent composition of V―O bonds increase. In addition, the covalent components of V―O_t are larger than those of corresponding V―O_b. The analysis on charge density indicates that the charge density of cluster decreases as the size of the clusters increases, resulting in a corresponding increase in stability. This study enhances the understanding of the electronic properties of POVs, and the trends indentified are expected to provide valuable information for applications of POVs.