Table presents changes in the mean hydrodynamic size and ζ-potential of particles synthesized under different conditions of C P , C S and β. It shows the presence of additive Ca 2+ ions inhibits CaCO 3 particles growth. When C P = 25 mM and β = 1, the particle size decreased from ∼7 µm in the absence of additive Ca 2+ ions (C S = 0 mM) to ∼1.4 µm when C S = 5 mM. It decreased to ∼300 nm when C S was further increased to 15 mM. This is more than 90% decrease, relative to the hydrodynamic size of particles obtained when C S = 0 mM. Regardless of C P and β, increases in C S was expected to result in further decrease in particle size. However, a different behavior is observed when C P > 25 mM. In these cases, the hydrodynamic particle size decreased with increasing C S , but not beyond C S = 10 mM (Table ). For example, when C P = 50 mM and β = 0.5, the particle size decreased from ∼9 µm, when C S = 0 mM, to ∼600 nm when C S = 10 mM. However, it increased to ∼900