Li4Cs3B7O14: synthesis, crystal structure, and optical properties.

A new noncentrosymmetric polyborate, Li(4)Cs(3)B(7)-O(14), has been synthesized using the conventional solid state reaction method. It crystallizes in the trigonal space group P3(1)21 (No. 152) with unit cell parameters of a = 6.9313(6) Å, c = 26.799(3) Å, and Z = 3. The new structure contains an infinite three-dimensional matrix that is built from B(7)O(14) building blocks rarely found in anhydrous borate compounds and LiO(n) (n = 4, 5), CsO(n) (n = 9, 10) polyhedra. The optical characterization of the compound indicates that the compound is phase matchable, and the UV cutoff edge is below 190 nm. IR spectroscopy, thermal analysis, and second-harmonic generation were also performed on the reported material.