Ab initio G2(MP2) calculations of the potential energy surface for Be+CO2→BeO+CO show that the reaction proceeds by formation of the cyclic BeOCO intermediate, 6.9 kcal/mol below the reactants, with a barrier of 22.8 kcal/mol. From the cyclic BeOCO structure the reaction continues to produce the linear OBeOC complex, 4.6 kcal/mol above the reactants, with a barrier of 13.0 kcal/mol relative to the reactants. The OBeOC complex decomposes to BeO+CO without an exit barrier. The calculated endothermicity of the Be+COCO2→BeO+CO reaction is ca. 26 kcal/mol. with 66 kcal/mol for Mg+CO2→MgO+CO and 125 kcal/mol for unimolecular decomposition of CO2, making beryllium atoms more efficient than magnesium atoms in the reforming of carbon dioxide into carbon monoxide.
