Synthesis, Structure Characterization and Thermal Analysis of a New Cadmium Zinc Borate in the Pseudo-binary System Cd3B2O6-Zn3B2O6

摘要

Cd-rich portion of the pseudo-binary system Cd_3B_2O_6-Zn_3B_2O_6 was investigated. A new cadmium zinc borate, Cd_(2.42)Zn_(0.58)B_2O_6, was synthesized successfully by a traditional solid-state reaction method. The compound crystallizes in the monoclinic space group C2/c with a = 17.3048, b = 8.4356, c = 10.2962 ?, β = 93.157°, V = 1500.7(2) ?~3, Dc = 5.683 g/cm^3, F(000) = 2301, Z = 24, R = 0.0351 and w R = 0.0741. In its structure, BO3 triangle, CdO_6 and Cd O5(or ZnO 5) polyhedra are joined together by sharing bridging O atoms to form an intricate three-dimensional framework. A comparison of the structures of Cd_(2.42)Zn_(0.58)B_2O_6, α-Cd_3B_2O_6 and β-Cd_3B_2O_6 is presented. The IR spectrum confirms the presence of BO3 unit. The UV cut-off wavelength of Cd_(2.42)Zn_(0.58)B_2O_6 is 313 nm. The differential thermal analysis(DTA) suggests that Cd_(2.42)Zn_(0.58)B_2O_6 is an incongruent melting compound.