The electronic energy band structures of pyroborate calcium

The title compound has been synthesized. On the basis of the determined sin gle - crystal structure data of this compound, the electronic structures ar e calculated using the INDO/S method with configuration interactions, follo wing combination with the sum - over - state method. The linear polarizabil ity of micro - species Ca2B2O5 is obtained, and the average refractive inde x is estimated for hulk Ca2B2O5. It is shown that the valence band has the contributions from the 2p orbitals of B and O atoms, while the low edge of conduction band has the main contributions from the Ca atoms, and the charg e transfers from the oxygen atomic orbital to calcium atomic orbital make t he significant contributions to the polarizability.