CsBO(OH)2: a new hydroxyborate with the rare [BO(OH)2] group and a deep ultraviolet cutoff edge

Abstract

In this paper, we propose that the hydroxylation of the O atoms in the [BO₃] groups can regulate the parallel arrangement of the [BO₃] groups and simultaneously blueshift the ultraviolet (UV) cutoff edge, which is an effective strategy for designing deep-ultraviolet (DUV) birefringent materials. A new hydroxyborate CsBO(OH)₂ was innovatively obtained, which exhibits pseudolayers assembled by the rare [BO(OH)₂] groups interconnected via hydrogen bonds. CsBO(OH)₂ exhibits both large birefringence and a DUV cutoff edge, which indicates its potential for forming DUV birefringent crystals.