Oxalate chlorideAn oxalate chloride or oxalato chloride is a mixed anion compound contains both oxalate and chloride anions.Related compounds include oxalate fluorides and oxalate bromides.ProductionOxalate chlorides may be produced by treating an oxalate salt with concentrated hydrochloric acid, or with a metal oxide dissolved in oxalic acid and hydrochloric acid solutions that are evaporated.