CdInO(BO3): An oxyborate birefringent material explored from d10 metal compounds

Birefringent crystals are particularly important in optical communication and laser industries. Herein, we report the synthesis, structures, optical properties, and theoretical analyses of an oxyborate birefringence material CdInO(BO 3 ). It has an interesting sandwich-like basic building unit (BBU) constructed by [CdO 4 ] 6− chains and [InO 4 ] 5− chains. CdInO(BO 3 ) possesses an experimental band gap of 3.65 eV and an ultraviolet (UV) cut-off edge about 295 nm. Moreover, it exhibits a large birefringence (0.136@1064 nm), which mainly originates from the parallel arrangement of the isolated [BO 3 ] groups. This discovery indicates that CdInO(BO 3 ) can be a promising birefringent material.