Synthesis and Structure of Two New Cadmium Carbonates at Extreme Conditions

Abstract

We synthesized CdC 2 O 5 and a new high-pressure polymorph of CdCO 3 by laser heating otavite, CdCO 3 , in CO 2 at 43 GPa. The structure of CdC 2 O 5 contains pyramidal [C 4 O 10 ] 4− building blocks formed by [CO 4 ] tetrahedra, where the carbon is in 4-fold coordination. In addition, we found a new monoclinic (P2 1 /c) highpressure polymorph of CdCO 3 with trigonal [CO 3 ] 2− groups. Both new structures were characterized by single-crystal X-ray diffraction, Raman spectroscopy, and DFT calculations.