Hydrothermal synthesis and crystal structure analysis of two new cadmium bismuthates, CdBi ₂ O ₆ and Cd _0.37 Bi _0.63 O _1.79

Two new cadmium bismuthates, CdBi ₂ O ₆ and Cd _0.37 Bi _0.63 O _1.79 , were prepared by hydrothermal reaction using NaBiO ₃ ·nH ₂ O 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 MnSb ₂ O ₆ -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 R _wp =4.59% and R _p =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 R _wp =4.79% and R _p =3.57%. These new bismuthates exhibit no photocatalytic activity under visible light.