Assessing the stability fields of molecular and polymeric CO2

We investigated the stability of polymeric CO2 over a wide range of pressures, temperatures, and chemical environments. We find that the I (4) over bar 2d polymeric structure, consisting of a three-dimensional network of corner sharing CO4 tetrahedra, forms at 40-140 GPa and from a CO-N-2 mixture at 39 GPa. An exceptional stability field of 0-286 GPa and 100-2500 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 sp(3) hybridized orbitals of carbon in a closed-packed oxygen sublattice.

Automated summary

We studied the stability of polymeric CO2 under various pressures, temperatures, and chemical environments. The I (4) over bar 2d polymeric structure, composed of a three-dimensional network of corner sharing CO4 tetrahedra, was found to form at 40-140 GPa and from a CO-N-2 mixture at 39 GPa. This structure exhibits exceptional stability in the range of 0-286 GPa and 100-2500 K, making it a viable candidate for planetary interiors. The stability of the tetrahedral polymeric motif of CO2-V is attributed to the rigid sp(3) hybridized orbitals of carbon in a closed-packed oxygen sublattice.