Oxalate
= Oxalate
{title2=$\mathrm{C_2O_4^{2-}}$}
{wiki}
<Oxalate> is the dianion $\mathrm{C_2O_4^{2-}}$ formed by loss of two <protons> from <oxalic acid>. Its oxygen donors can bind a metal centre as a <chelate>.
Precipitation of calcium oxalate illustrates the difference between a dissolved molecular ion and a solid salt. Changing the metal counterion or the <pH> can change <solubility> and hence whether <oxalate> remains in <chemical solution>.