AIO3·H6TeO6 (A = NH4+, Rb+): Two telluric acid and iodate Co-crystalline compounds with second harmonic generation response

Two co-crystalline compounds containing telluric acid and iodate, namely AIO 3 ·H 6 TeO 6 (A ​= ​Rb + , NH 4 + ), were investigated as potential nonlinear optical materials. They crystallize into isostructural and consist of isolated [IO 3 ] group and [H 6 TeO 6 ] molecule linked by hydrogen bonds and charge interactions of Rb + /NH 4 + . They show phase-matching second harmonic generation responses with moderate intensity of 1.2 ​× ​KDP (Rb + ) and 1.1 ​× ​KDP (NH 4 + ). They also possess large optical band gaps over 4.25 ​eV and can be easily grown from aqueous solutions. The local dipole moment calculations based on the structures of AIO 3 ·H 6 TeO 6 (A ​= ​K + , Rb + , NH 4 + ) series of compounds indicate that the change of A + cation in their structural frame causes a slight change in the arrangement directions of [IO 3 ] and [Te(OH) 6 ] groups, and further induces their SHG responses of different intensities at the macroscopic level.