Hydrothermal synthesis and crystal structure analysis of two new cadmium bismuthates, CdBi₂O₆ and Cd_0.37Bi_0.63O_1.79

Two new cadmium bismuthates, CdBi2O6 and Cd0.37Bi0.63O1.79, were prepared by hydrothermal reaction using NaBiO3·nH2O as one of the starting compounds. The crystal structures of these compounds were refined by using synchrotron X-ray powder diffraction data. The former bismuthate has a MnSb2O6-type structure with a hexagonal cell (space group: P321); the cell parameters were a = 9.3641(7) and c = 4.9523(3) Å, and the final R-factors were Rwp = 4.59% and Rp = 3.04%. The latter bismuthate has a fluorite-type structure with a cubic cell (space group: Fm3¯m) of a = 5.4110(4) Å, and the final R-factors were Rwp = 4.79% and Rp = 3.57%. These new bismuthates exhibit no photocatalytic activity under visible light.