Non-molecular CO2 Under Pressure

ICTP physicist Sandro Scandolo and former diploma student Javier Montoya are authors in a recently published paper that describes the structural properties of CO₂ under pressures of over 30GPa. The paper, published in PNAS and titled "Partially collapsed cristobalite structure in the non molecular phase V in CO₂", reports the experimental results of studying the structure of CO₂-V (a solid phase of CO₂ that can exist only under high pressure conditions).

High-pressure physics is the study of how properties of matter are modified under high pressure, and studies on non-molecular CO₂ have become an important field over the past decade.

Theoretical studies on the CO₂-V structure had indicated that its structure could be similar to silicon in SiO₂, but so far there had been no conclusive experimental verification.

By using synchrotron X-ray diffraction, optical spectroscopy, and computer simulations, Montoya, Scandolo et al. investigated CO₂-V obtained from molecular CO₂ under pressures of 40-50 GPa and temperatures more than 1500 K and confirmed  part of the theoretical prediction.

The results add to the knowledge of carbon chemistry with mineral phases similar to SiO_2, and have potential implications for studies on Earth and planetary interiors, the authors have stated.