First-principles study of structure and stability in Si–C–O-based materials

Mechanistic study of pressure and temperature dependent structural changes in reactive formation of silicon carbonate

The structure changes of silicon carbonate with pressure and temperature are explored based on systematic ab initio molecular dynamics simulations.

A novel crystalline SiCO compound

Ab initio evolutionary structural searches have been performed on Si_xC_yO_2(x+y) compounds.

Carbon enters silica forming a cristobalite-type CO2-SiO2 solid solution

Extreme conditions permit unique materials to be synthesized and can significantly update our view of the periodic table. In the case of group IV elements, carbon was always considered to be distinct with respect to its heavier homologues in forming oxides. Here we report the synthesis of a crystalline CO2-SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell (P = 16-22 GPa, T>4,000 K), showing that carbon enters silica. Remarkably, this material is recovered to ambient conditions. X-ray diffraction shows that the crystal adopts a densely packed α-cristobalite structure (P4(1)2(1)2) with carbon and silicon in fourfold coordination to oxygen at pressures where silica normally adopts a sixfold coordinated rutile-type stishovite structure. An average formula of C0.6(1)Si0.4(1)O2 is consistent with X-ray diffraction and Raman spectroscopy results. These findings may modify our view on oxide chemistry, which is of great interest for materials science, as well as Earth and planetary sciences.