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

In this Article, we reported the synthesis of a crystalline CO2–SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell at pressures between 16 and 22GPa and temperatures greater than 4,000K, and showed that carbon enters silica. We have now reanalysed all our X-ray diffraction patterns, in particular those at room pressure where potential volatile components (for example, CO2) are absent, making data interpretation as simple and clean as possible1. Indeed, we find that orthorhombic b-ReO2 (Pbcn) provides a better fit to the temperature-quenched new phase than tetragonal cristobalite. This possibility was also indicated by experimental results from Santamaria-Perez and co-workers2. Hence what we previously interpreted as a CO2–SiO2 solid solution now appears to be ReO2, indicating the decomposition of CO2 leading to the oxidation of Re from the gasket, which is found to diffuse into the sample in the laser heating experiment. The authors therefore wish to retract this Article.