Explorations of New SHG Materials in Mercury Iodate Sulfate System.

Through systematic experiments, two novel mercury iodate sulfates, namely, Hg 2 (IO 3 ) 2 (SO 4 )(H 2 O) and Hg 2 (IO 3 ) 2 (SO 4 ) were obtained. They crystallize in monoclinic space group C2 and C2/c, respectively. Hg 2 (IO 3 ) 2 (SO 4 )(H 2 O) exhibits the [Hg(IO 3 )] + polar cationic layer inherited from Hg(IO 3 ) 2 and the three-dimensional (3D) framework inherited from HgSO 4 . This enables Hg 2 (IO 3 ) 2 (SO 4 )(H 2 O) to generate a strong second harmonic generation (SHG) response of 6 times that of KH 2 PO 4 (KDP). The structure of Hg 2 (IO 3 ) 2 (SO 4 ) is very similar to that of Hg 2 (IO 3 ) 2 (SO 4 )(H 2 O), and they can be transformed into each other. Hg 2 (IO 3 ) 2 (SO 4 )(H 2 O) shows a large optical band gap of 3.98 eV and a high dehydration temperature of 250 °C. This study indicates that by reasonable design, the introduction of multiple functional groups into a compound may combine their advantages to achieve good overall optical performance.