Question

Is calcium oxalate soluble in water?

Answer 1

According to http://www.americanelements.com/caoxl.html , calcium oxalate, `"CaC"_2"O"_4"` is "highly insoluble in water."

Answer 2

No, calcium oxalate, `CaC_2O_4`, is not soluble in aqueous solution.

The solubility of calcium oxalate is listed at 6.7 mg/L, or `6.7 * 10^(-3)"g/L"`, far less than the `"1 g/L"` threshold used to distinguish between soluble and insoluble compounds.

In fact, calcium oxalate is one of the major components of kidney stones.