LaTeBO5: a new borotellurite with a large birefringence activated by the highly distorted [Te(iv)O4] group.

A new borotellurite, LaTeBO5, containing the highly distorted [Te(iv)O4] group has been synthesized. Interestingly, it exhibits a wide ultraviolet transmittance range and large birefringence (0.080@1064 nm). The response electron distribution anisotropy approximation and dipole moment calculation demonstrate that the synergistic effect of the highly asymmetric [Te(iv)O4] and BO3 groups is conducive to its large birefringence.