Ba₂B₇O₁₂F with novel FBB [B₇O₁₆F] and deep-ultraviolet cut-off edge

A new member in the barium fluorooxoborate family, namely Ba₂B₇O₁₂F, was obtained by the high-temperature solution method in an open system under ambient pressure. The structure features a new fundamental building block [B₇O₁₆F], which interconnects with each other to form the anionic framework [B₇O₁₂F]_∞ with two different caves in which the cations reside. The experiment result indicates that Ba₂B₇O₁₂F possesses a deep-ultraviolet cut-off edge below 180 nm.