A chemical which occurs naturally in many plants. Its hydrated form has the chemical formula of (CO2H)2·2H2O which melts at 101-102°C. Its anhydrous form (which does not have the ·2H2O) melts at 189-190°C. At room temperature it is a transparent solid. It is a strong irritant which can be toxic when inhaled or ingested. It is used as to clean the radiators of automobiles and in the tanning of leather and the bleaching of textiles.