Synthesis, crystal structure and optical properties of the first bromine-containing iodate: Pb2IO3Br3

The single crystal of Pb2IO3Br3 was successfully synthesized by the hydrothermal method, which is the first case of bromine-containing iodate. The polycrystalline powder of the compound was synthesized and its purity was characterized by X-ray single crystal diffraction. Pb2IO3Br3 crystallized in the space group P 1(—) (No. 2). In the structure of Pb2IO3Br3, the isolated [IO3]- groups are in a reverse arrangement to fill in the tunnels of the three-dimensional network that is composed of [PbBrn] polyhedra. In addition, first-principle calculations have been performed to investigate the relationship between the crystal structure and the optical properties. The result indicates Pb2IO3Br3 possesses a moderate birefringence (Δn = 0.064, λ = 1064 nm), which is mainly originated from the umbrella-like [IO3] groups and the [PbOBr] polyhedra.