Yes, carbonates of alkaline earth metals (e.g. magnesium and calcium) are solids at STP and more stable than carbon dioxide. See section 7.2.2 "Chemistry of min

Yes, carbonates of alkaline earth metals (e.g. magnesium and calcium) are solids at STP and more stable than carbon dioxide. See section 7.2.2 "Chemistry of mineral carbonation" in this IPCC report: https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_chapter7-1.pdf https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_chapte... Even at the low partial pressure of atmospheric CO2 and at ambient temperature, carbonation of metal oxide bearing minerals occurs spontaneously, though on geological time scales (Robie et al., 1978; Lasaga and Berner, 1998). Limitations arise from the formation of silica or carbonate layers on the mineral surface during carbonation that tend to hinder further reaction and to limit conversion (Butt et al., 1996) and from the rate of CO2 uptake from the gas phase in the case of aqueous reactions. The challenge for mineral carbonation is to find ways to accelerate carbonation and to exploit the heat of reaction within the environmental constraints, for example with minimal energy and material losses.