Mei-Jun Zou, Dong-Ling Liu, Xiao-Liang Zhou, Yi-Nan Zhang, You‐Zhao Lan, Jian‐Wen Cheng
A new noncentrosymmetric mixed alkaline metal borate-formate, Na 2 KB 6 O 10 (HCOO) ( 1 ), has been successfully synthesized under surfactant-thermal conditions. Compound 1 features a three-dimensional B–O framework constructed from [B 6 O 13 ] 8– building units, with two distinct sets of nine-membered-ring channels extending along different crystallographic directions, in which Na +, K +, and HCOO – ions are located for charge balance. It exhibits a broad transparency window in the ultraviolet (UV) region, and its second harmonic generation response is determined to be 1.4 times that of KH 2 PO 4 with phase-matching behavior. This mixed alkaline metal borate-formate is demonstrated to be a promising UV-transparent nonlinear optical crystal.