Sodium tungstate is a white opaque crystalline mass of sodium ions combined with tungstate ions, which becomes yellow chlorine oxide when heated with chlorine gas. Sodium tungstate reacts with strong acids (except hydrofluoric acid) to produce yellow tungstic acid that is insoluble in water, reacts with phosphoric acid or phosphate to produce phosphotungstic heteropoly complex, reacts with tartaric acid, citric acid, oxalic acid and other organic acids to produce corresponding organic acid complexes.