BaB2O3F2: A Barium Fluorooxoborate with a Unique [B2O3F]− Layer and Short Cutoff Edge

Abstract Substitution of oxygen by fluorine in the borate group offers a materials platform from which intriguing structure and functionality may arise. Herein, we report a new fluorooxoborate, BaB 2 O 3 F 2 , synthesized by introducing the F atoms into the BaO–B 2 O 3 system. BaB 2 O 3 F 2 exhibits a unique oxyfluoride layer [B 2 O 3 F] − and a deep‐ultraviolet cutoff edge below 180 nm. The effect of the introduction of F atoms on the structure and optical property of the borate group has been investigated; this should be useful to further expand borate chemistry and materials.