NHIOF and (NH)(IOF)·HO: A Series of Ammonium-Containing Fluoroiodates with Wide Band Gaps.

A series of ammonium-containing fluoroiodates, NHIOF and (NH)(IOF)·HO, with isolated [IOF] units have been fabricated by a fluorine-oxygen substitution strategy from NHIO. The two compounds crystallize in the orthorhombic system, but in different space groups, noncentrosymmetric 2 for NHIOF and centrosymmetric for (NH)(IOF)·HO, and show wide band gaps of 4.53 eV for (NHIOF) and 4.55 eV for ((NH)(IOF)·HO). In addition, NHIOF exhibits a 1.2 × KDP second harmonic generation response, a short ultraviolet cutoff edge in iodates, and a good crystal growth habit. The crystal of NHIOF with a size of 11 × 5 × 2 mm was obtained by the aqueous solution method. The results enrich the structural diversity of iodate and supply a greater understanding of the design of new functional materials based on the fluoroiodates.