Extended covalent solid forms of carbon dioxide with carbon–oxygen single bonds

Recent evidence points toward the existence at high pressures of extended covalent solid forms of carbon dioxide with carbon–oxygen single bonds. A (CO2)2n+1 polyspirotrioxane (polyspiro orthocarbonate) polymer structure proposed by us in 1992 and predicted as thermodynamically feasible and synthesizable under high pressure is consistent with the recent experimental findings.