Synthesis, crystal structure, optical property and theoretical studies of a noncentrosymmetric telluromolybdate CoTeMoO6

Polycrystalline CoTeMoO6 has been synthesized, and CoTeMoO6 crystals have been grown by spontaneous crystallization. Band structure, density of states, charge density, electronic structures and optical properties of CoTeMoO6 crystal were calculated by using a first-principles method for the first time. Optical and nonlinear optical properties of CoTeMoO6 crystal were measured. Structure and charge density analyses indicate that cleavage maybe exist in CoTeMoO6 crystal. The experiment results of optical properties show that a strong absorption band exhibits at 458-692 nm in the visible region. The absorption band plays an important role in the coloration of CoTeMoO6 crystal. The SHG responses of CoTeMoO6 with a 1.06 μm laser is much weaker than that of KDP, which can be ascribed to the absorption band caused by spin-allowed d-d transitions of Co2+ ions. Thus CoTeMoO6 crystal is not suited to be used as nonlinear optical material in the Vis-NIR region.