We investigated the stability of polymeric CO2 over a wide range of pressures, temperatures, and chemical environments. We find that the I-42d polymeric structure, consisting of a three-dimensional network of corner sharing CO4 tetrahedra, forms at 40-140 GPa and from a CO-N2 mixture at 39 GPa. An exceptional stability field of 0 to 286 GPa and 100 to 2500 K is documented for this structure, making it a viable candidate for planetary interiors. The stability of the tetrahedral polymeric motif of CO2-V is a consequence of the rigidity of sp3 hybridized orbitals of carbon in a closed-packed oxygen sublattice.
@article{arxiv.2304.11224,
title = {Assessing the stability fields of molecular and polymeric CO2},
author = {Alexander F. Goncharov and Elena Bykova and Maxim Bykov and Eric Edmund and Jesse S. Smith and Stella Chariton and Vitali B. Prakapenka},
journal= {arXiv preprint arXiv:2304.11224},
year = {2023}
}