Sodium potassium tartrate is an organic compound with the chemical formula NaKC₄H₄O₆. It is produced by neutralizing tartaric acid, derived from grape byproducts, with sodium carbonate or sodium hydroxide. C₄O₆H₄KNa exists in two forms: D-type and DL-type. The D-type is a colorless transparent crystal with a density of 1.79 g/cm3 and a melting point of 75°C. It exhibits efflorescence in hot air, loses partial crystalline water at 60°C, and loses all crystalline water at 215°C. Its solubility in water is 18.4 g per 100 ml at 0°C, 40.6 g per 100 ml at 10°C, 54.8 g per 100 ml at 20°C, and 76.4 g per 100 ml at 30°C. It is insoluble in alcohol. It possesses chelating properties and can form soluble complexes in alkaline solutions with metal ions such as aluminum, beryllium, cadmium, cobalt, molybdenum, niobium, lead, nickel, palladium, platinum, rhodium, antimony, tin, tantalum, tungsten, zinc, (copper), as well as selenium and tellurium.