Semiconductor compounds with cubic pyrochlore structure A2B2O6O', obtained in a wide range of compositions in the Bi2O3–Na2O–Fe2O3–WO3system by the hydrothermal method (T = 200 °C, P ∼ 7 MPa, pH ∼ 5), were studied by powder XRD, EDX microanalysis, SEM, Mössbauer spectroscopy, diffuse reflectance spectroscopy, X-ray and ultraviolet photoelectron spectroscopy techniques.It was shown that metal atoms are distributed over structurally non-equivalent positions as follows: (Bi, Na, □)2(Fe, W)2O6O'δ(□ are cation vacancies). The static displacements of atoms from the “ideal” Wyckoff positions (Bi3+cations (16d→96g) and oxygen anions (8b→32e)) were detected in the A2O' sublattice.The band gap value (Eg) for the indirect allowed electronic transitions, as well as the energetic position of valence band maximum (EVBM) and conduction band minimum (ECBM) relative to the vacuum level, do not depend on the chemical composition of the obtained pyrochlores within the error limits and amount to ∼2.1 eV, −5.9 eV, and −3.8 eV, respectively. © 2025 Elsevier B.V., All rights reserved.