# Why Calcium Oxalate is insoluble in acetic acid?

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

1. High Lattice Energy and
2. 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.

• You have omitted to consider acid-basis relations, particularly the relative acidity/alkalinity of respective cunjugated acid/base pairs. Apr 21, 2020 at 8:55
• Yes, but what may be the reason for other facts, i am more interested in knowing how to compare properties like solubility and lattice energy
– user91694
Apr 21, 2020 at 10:18
• Such things are more related to solubility product. For solubility itself, you have to involved the side acid-base equilibrium reactions. The play essential role. Apr 21, 2020 at 12:14