Calcium oxalate is insoluble in acetic acid, but not it's carbonate, oxide and hydroxide.
From internet, it is even considered as a test to distinguish calcium oxalate from it's carbonate and oxide. The reason from the resources which i had searched, only gave factual reasons such as
- High Lattice Energy and
- Low solvation energy of $Ca(C_2O_4)$
But intuitively the "short sized" compounds like $CaO$ and $Ca(OH)_2$ must have better packing and more lattice energy, then why much bigger calcium oxalate have higher lattice energy?
Also, i am clueless about how to compare solvation energy of different compounds. I think it has to do with polarity of the solute and the solvent. Any help will be appreciated.
Edit: I had omitted the relative basicity of oxide, hydroxide and carbonate of calcium but i am more interested in knowing how to compare the lattice energy and solubility of the given compounds.