Synthesis, structure characterization and optical properties of a new lead cadmium borate

A new ternary borate, Pb3Cd3(BO3)4, has been synthesized by solid-state reaction at 530 °C. The compound crystallizes in the hexagonal space group P63/m with a = 9.946(4), c = 7.003(5) Å, and Z = 2. The crystal structure consists of one-dimensional (1D) long [PbO5]∞ tubes. The tubes are further connected by BO3 to generate a three-dimensional framework with the six-member tunnels along the c axis, where Cd atoms locate and the CdO6 octahedra form 1D chain. The IR spectrum confirms the presence of BO3 unit. The UV–Vis–IR diffuse reflectance spectrum exhibits a band gap of about 3.56 eV. The DSC analysis suggests that Pb3Cd3(BO3)4 is an incongruent melting compound.