Knowra Potassium sodium tartrate Potassium sodium tartrate Potassium sodium tartrate is a crystalline double salt of potassium, sodium, and tartaric acid, commonly called Rochelle salt. It is used in food and medicine and has strong piezoelectric properties.
Tartaric acid : A naturally occurring organic acid with two carboxyl groups and two hydroxyl groups, found in grapes and other plants. Tartrate, the anion in Rochelle salt, is the deprotonated form of this acid.
Piezoelectricity : The generation of electric polarization in certain materials when they are mechanically stressed, and the converse deformation under an electric field. Rochelle salt is a classic piezoelectric crystal, producing charge when compressed or bent.
Pierre Seignette : A French pharmacist associated with the seventeenth-century preparation of Rochelle salt in La Rochelle. The salt’s traditional name honors the pharmacist credited with its preparation.
Food additive : A substance intentionally added to food to perform a technological function such as preservation, coloring, or acidity regulation. Potassium sodium tartrate is used as an acidity regulator and stabilizer in some foods.
Potassium bitartrate : A sparingly soluble potassium hydrogen tartrate found naturally in wine and known as cream of tartar. Unlike Rochelle salt, it contains potassium and hydrogen tartrate rather than both potassium and sodium.
Double salt : A crystalline compound formed from two different salts in a fixed proportion, which dissociates into their ions in solution. Rochelle salt combines potassium and sodium tartrates in one crystal lattice.
Ferroelectricity : A property of materials with spontaneous electric polarization that can be reversed by an applied electric field. Rochelle salt is ferroelectric over a limited temperature range, unlike its broader piezoelectric response.
Rochelle : A port city on France’s Atlantic coast, historically known in English as Rochelle. Rochelle salt takes its common name from this city, where it was first prepared.
Pharmaceutical excipient : An ingredient in a medicine that supports formulation, manufacture, stability, or administration rather than providing its main therapeutic effect. Rochelle salt has served in medicinal preparations, including as a laxative ingredient.
Sodium tartrate : A sodium salt of tartaric acid that contains no potassium cation. It shares the tartrate anion but lacks Rochelle salt’s mixed potassium-sodium composition.
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