Na₂ Cr₂O₇_2H₂O Poisonous, red to orange deliquescent crystals; soluble in water, insoluble in alcohol; melts at 320_C; loses water of hydration upon prolonged heating at 105_C; used as a chemical intermediate and corrosion inhibitor and in the manufacture of pigments, leather tanning, and electroplating. Also known as bichromate of soda; sodium acid chromate; sodium bichromate.