Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of Tartaric Acid first prepared by an apothecary, Pierre Seignette, of La Rochelle, France. Potassium Sodium Tartrate and monopotassium phosphate were the first materials discovered to exhibit piezoelectricity.This property led to its extensive use in "crystal" gramophone pick-ups, microphones and earpieces during the post-World War II consumer electronics boom of the mid-20th Century. Such transducers had an exceptionally high output with typical pick-up cartridge outputs as much as 2 volts or more. Rochelle salt is deliquescent so any transducers based on the material deteriorated if stored in damp conditions.
| Chemical Name |
Potassium Sodium Tartrate; Potassium Sodium Tartrate Tetrahydrat； 2,3-dihydroxy- (2R,3R)-, monopotassium monosodiumsalt； Rochelle salt Alkaline Tartrate |
|---|---|
| Molecular Formula | KNaC4H4O6·4H2O |
| Structural Formula |
|
| Molecular Weight | 282.23 |
| CAS No | 6381-59-5 (dihydrate) |
| Character | Colorless crystals or white crystal; specific gravity is 1.79; PH value is 6.8~8; the melting point is 70~80°C; Have efflorescence in the heat air, lose some water when heated to 60°C, and lose 3 water molecules at 100°C, become salt without water at 215°C. Freely soluble in water, insoluble in ethyl alcohol |
| Storage | Keep in an avoid light and dry place. Seal preservation |
| Quality Standard | British Pharmacopoeia |
| Term of validity |
2 years  |
