NH4IO2F2 and (NH4)(3)(IO2F2)(3)center dot H2O: A Series of Ammonium-Containing Fluoroiodates with Wide Band Gaps

A series of ammonium-containing fluoroiodates, NH4IO2F2 and (NH4)(3)(IO2F2)(3)center dot H2O, with isolated [IO2F2] units have been fabricated by a fluorine-oxygen substitution strategy from NH4IO3. The two compounds crystallize in the orthorhombic system, but in different space groups, noncentrosymmetric Pca2(1) for NH4IO2F2 and centrosymmetric Pnma for (NH4)(3)(IO2F2)(3)center dot H2O, and show wide band gaps of 4.53 eV for (NH(4)IO(2)F2) and 4.55 eV for ((NH4)(3)(IO2F2)(3)center dot H2O. In addition, NH4IO2F2 exhibits a 1.2 x KDP second harmonic generation response, a short ultraviolet cutoff edge in iodates, and a good crystal growth habit. The crystal of NH4IO2F2 with a size of 11 x 5 x 2 mm(3) 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.

Automated summary

A series of ammonium-containing fluoroiodates were synthesized using a fluorine-oxygen substitution strategy, and their crystal structures and properties were investigated. The compounds exhibited wide band gaps and a good second harmonic generation response, contributing to the structural diversity of iodates and the design of new functional materials.