The first lead fluorooxoborate PbB5O8F: achieving the coexistence of large birefringence and deep-ultraviolet cut-off edge.

Herein, the first lead fluorooxoborate PbB5O8F has been structurally designed following a strategy of fluorine introduction into borates. PbB5O8F presents the first case of possessing the [B5O10F]6- fundamental building block. More importantly, PbB5O8F fully achieves the coexistence of large birefringence and deep-ultraviolet cut-off edge. This short cut-off edge sets a new record among lead borates.