Potassium sodium tartrate tetrahydrate KNaC4H4O6.4H2O M = 282,23 g/mol EC No. 205-698-2 CAS No. 6381-59-5 This is an international mail and delivery time can vary widely. Chemical Grade Definitions: Pure p.a - High purity analytical reagents. Suitable for laboratory and general use. Pharm/Food - Acceptable for food, drug or medicinal use. May be used for most laboratory purposes. Pure - Good quality chemicals. May be used for most laboratory purposes, educational, domestic, craft applications. Not pure enough to be offered for food. Technical - Good quality for educational, domestic, handicraft, agricultural applications. Not pure enough to be offered for food.