Electronic structure of ZnSb2O6 was investigated using the discrete variational (DV)-Xα method on the model cluster [Zn5Sb10O56] 52-. In the calculation, the band gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied MO (LUMO) was 3.80 eV. In the valence band, Sb-O and Zn-O bondings are considered to be not perfectly ionic but partially covalent because of the hybridization of O 2p orbitals with Sb 5sp and Zn 3d orbitals. Furthermore, ZnSb2O6 crystal is expected to have a large electron mobility because Sb 5s orbitals are dominant at the bottom of the conduction band. The calculated net charges are +1.48e for Zn, -1.20e for O and +3.02e for Sb. The bond overlap populations are calculated to be 0.09 and 0.29 for Zn-O and Sb-O bondings, respectively. These results show that Sb-O bonding is more covalent than Zn-O bonding in ZnSb2O6 crystal.
