Abstract Two modifications of Te2MoO7 oxide have been prepared by different synthetic methods. The crystal structure and composition have been studied by X-ray diffraction analysis and X-ray microanalysis. The phase of α-Te2MoO7 has been synthesized by solid-state reaction from ammonium salts and characterized by monoclinic structure with P21/c. The β-Te2MoO7 compound has been formed in hydrothermal conditions and has amorphous nature. The thermal behavior of β-Te2MoO7 modification is characterized by the phase transition into α-form, however after melting the amorphous state has restored. The electron structure has been investigated experimentally by X-ray photoelectron spectroscopy and UV-vis diffusion reflectance spectra and theoretically by approximation using atomic electronegativity. Despite the same composition, the band gap of β-Te2MoO7 corresponds to visible light, whereas α-Te2MoO7 adsorbs light in UV region. The both modifications are able to generate superoxide radicals in vacuum or air and hydroxyl radicals in water under irradiation. The HPLC-MS analysis has shown the quite deep decomposition of dye and antibiotics by α-Te2MoO7, whereas amorphous phase almost does not lead to any oxidation.