Na7(SeO4)3(IO3) and K2(SeO4)[IO2(OH)]: two new iodate-selenates with short-wave UV cutoff edge and large birefringence†
Abstract
Herein, I5+ with stereochemically active lone pairs (SCALP) was introduced into the selenate system, and two novel iodate-selenates were successfully obtained, Na7(SeO4)3(IO3) and K2(SeO4)[IO2(OH)]. Innovatively, both the title compounds are potential short-wave ultraviolet (UV) birefringent materials that possess large optical band gaps (4.57 eV and 4.27 eV, respectively) and large birefringence (0.087@546 nm and 0.101@546 nm, respectively). Simultaneously, the powder second harmonic generation (SHG) measurement reveals that Na7(SeO4)3(IO3) exhibits SHG responses of 0.6 × KDP (KH2PO4) with type-I phase matching. Detailed structural analysis and theoretical calculations confirm the excellent optical performance originating from the cooperative effect of [SeO4] and [IO3]/[IO2(OH)] functional units. This work indicates that the iodate-selenate system offers additional candidates for designing short-wave UV optical materials.
- This article is part of the themed collection: Journal of Materials Chemistry C HOT Papers