Syntheses, structures and optical properties of two new cadmium antimonites: Cs4Cd(SbF5)3(H2O)2 and Cd[Sb7O10(OH)](SO4).

The cadmium antimonite system is expected to become a promising candidate for exploring novel optical functional crystal materials, owing to the synergistic effect of the d10 transition metal and lone pair electrons. However, compounds in Cd2+-Sb3+-O/F systems are very rare. By utilizing the room-temperature solution evaporation and hydrothermal methods, two novel cadmium antimonite compounds, namely, Cs4Cd(SbF5)3(H2O)2 and Cd[Sb7O10(OH)](SO4), have been successfully synthesized. Cs4Cd(SbF5)3(H2O)2 features the first cadmium fluoroantimonite compound, forming a one-dimensional chain structure composed of SbF5 and CdF4O2 groups. Cd[Sb7O10(OH)](SO4) displays a new two-dimensional layered structure separated by isolated SO4 tetrahedra. Optical measurements revealed that both compounds have short UV absorption edges and moderate birefringence. Band structures and densities of states of the title compounds have also been evaluated.