The stability of CO₂ phases at pressures up to 1600 GPa is confirmed using evolution methods for predicting crystal structures. Stable CO₂ phases are as follows: \(I\bar {4}2d\) (to 279 GPa), \(P{{4}_{2}}{\text{/}}nmc\) (279–952 GPa), Pbcn (952–1018 GPa), and \(Pa\bar {3}\) (above 1018 GPa). The equations of state for stable CO₂ phases up to pressures of about 1600 GPa are calculated for the first time using ab initio methods and high-temperature calculations within the quasi-harmonic approximation. It is shown that high-pressure \(P{{4}_{2}}{\text{/}}nmc\), \(Pbcn\), and \(Pa\bar {3}\) phases have rather high bulk moduli (290–415 GPa). Phases with sixfold coordination of carbon atoms (Pbcn and \(Pa\bar {3}\)) have higher coefficients of thermal expansion in comparison with the \(P{{4}_{2}}{\text{/}}nmc\) phase.

使用预测晶体结构的演化方法证实了CO ₂相在高达1600 GPa 的压力下的稳定性。稳定的 CO ₂相如下：\(I\bar {4}2d\)（至 279 GPa）、\(P{{4}_{2}}{\text{/}}nmc\) (279– 952 GPa)、Pbcn (952–1018 GPa) 和\(Pa\bar {3}\)（1018 GPa 以上）。首次使用从头计算方法和准谐波近似内的高温计算计算了压力高达约 1600 GPa 的稳定 CO ₂相的状态方程。结果表明，高压\(P{{4}_{2}}{\text{/}}nmc\)、\(Pbcn\)和\(Pa\bar {3}\)相具有相当高体积模量 (290–415 GPa)。与\(P{{4}_{2}}{\text{/}}相比，碳原子六重配位相（Pbcn和\(Pa\bar {3}\) ）具有更高的热膨胀系数nmc\）相。