Abstract: In this paper, the effect of hydroxyl groups on CaCO3 mineral phases and their interfacial energies in biological-like fluids (alcohol-water mixtures) were studied. The results show that polyhydroxy alcohols are beneficial to the formation of metastable vaterite, and the addition of alcohols can increase the interfacial energies between calcite and vaerite. The decrease of total absoption site density due to the hydroxyl-oriented adsorption of alcohols is most likely the mechanism to increase the mineral interface, and the number of hydrogen bonds in solvents determines the degree of freedom of carbonate ions resulting in
the formation of vaterite, whose CO₃^{2 -} plane is nonparallel. In solvents with weak hydrogen net work, the calcite phase is the thermodynamic-favouriable phase due to the low interfacial energy between water and ethanol-water. The results show that the bio-mineralizing fluid can strongly affect the carbontion process through hydroxyl function group. By controlling the content of hydroxyl group in the fluid, the living organisms can select the formation site of calcium carbonate phase, which extends our understanding about the origine of stable biogenic calcium carbonates.

Key words: calcium carbonate, alcohol hydroxyl group, interfacial energy, biomineralization