Potassium Sodium Tartrate
The layman term for this chemical is Rochelle salt. It was first produced in the mid-1600’s by an apothecary in La Rochelle, France. It is a large, odorless and colorless crystal. It has a strong saline flavor, and it exhibits piezoelectric tendencies. This means that it works well as an electric conductor, which is why Rochelle salt was used heavily for radio equipment during the Second World War.
Potassium sodium tartrate is still sometimes used in electronic components. Other applications for this substance include laxatives, mirrors, and electroplating. It is highly stable, although it is classified as deliquescent, meaning that it absorbs moisture from the air and starts to break down. In some cases, Rochelle salt can be found in some food additives.
Because of its deliquescent nature, potassium sodium tartrate must be stored in an airtight container in a cool, dry area. Gloves and a breathing mask should be worn when handling this substance as direct exposure to the skin can cause mild irritation. In powdered form, inhalation may occur, which can cause breathing problems and illness.