# Why is calcium carbonate relatively insoluble in water?

In fact most carbonates are insoluble in water (the exceptions are?). Carbonate is a doubly charged negative ion that should form strong electrostatic bonds with metal ions - the doubly charged calcium ion, $C {a}^{2 +}$, should form strong ionic bonds, and indeed it does.
As physical scientists, however, we seek actual data, and I confess that I cannot find an appropriate table. I did find ${K}_{s p} = 3.3 \times {10}^{-} 9$, which corresponds to approx. 10 mg per litre at $25$ ""^@C.
Should the $p H$ of the solution be increased, would you expect the solubility of calcium carbonate to go up or down? Will the carbonate ion remain as carbonate at lower $p H$?