Na: A New Lanthanum Sodium Borate With Infinite 2d Layer 2 And Moderate Birefringence

A new rare earth borate Na2La2B10O19 was successfully synthesized by spontaneous crystallization in a high temperature solution. It crystallizes in the centrosymmetric (CS) space group C2/c with an infinite two-dimensional (2D) double layer which is composed of the fundamental building block (FBB) [B5O12](9-). The calculated birefringence of the compound is 0.06 @1064 nm which mainly originates from the contributions of the B-O anion group according to the first-principles study.