Ab initio calculations of the electron density are fulfilled for bismuth vanadate polymorphs: β-Bi4V2O11 and γ-Bi4V2O11. A semiconductor-type spectrum is obtained for both phases. The calculated bandgap value decreases in the direction from the β to γ phase. Chemical bond analysis shows an increase in the strength of covalent interactions in the series of Bi-V, Bi-O, and V-O bonds. The V-O bond strength in β-Bi4V2O 11 is appreciably higher than in the γ phase. The relatively weak binding of oxygen in the tetragonal structure of γ-Bi 4V2O11 confirms the possibility of easier oxygen transport in the γ phase than in the β phase. The stability of the bismuth vanadate polymorphs and the oxygen-disorder features in the γ-Bi4V2O11 structure are discussed using the results of calculation of the total energies of the phases. Bond overlap population analysis explains the existence of the homogeneous range and the feasibility of doping β-Bi4V2O11 and γ-Bi4V2O11. The possibility of using four-and five-charged d cations as stabilizers of the crystal structure of bismuth vanadates is discussed.