Hybrid crystals of calcium carbonate and amino acids

Pie have investigated the effects of amino acids on the crystallization of calcium carbonate (CaCO3), and the reactivity between amino acids and CaCO3 . Noncharged-polar and acidic amino acids are highly incorporated into CaCO 3 and stabilize cauliflower-like grains composed of vaterite which is therm odynamically unstable in the CaCO3 polymorphs. Amino acids in the hybrid Ca CO3 form radicals different from those in crystalline amino acids by X-ray irradiation. The results imply that the hybrid carbonate can provide a reac tion field for organic synthesis. We also propose models for the bond betwe en amino acids and CaCO3 using semiempirical approximation procedures.