Oxalate

Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula C2O2−4. This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na2C2O4), and several esters such as dimethyl oxalate ((CH3)2C2O4). It is a conjugate base of oxalic acid. At neutral pH in aqueous solution, oxalic acid converts completely to oxalate.