EDTA

EDTA is the chemical compound ethylene diamine tetraacetic acid. EDTA or its disodium salt is a chelating agent, forming coordination compoundss with most divalent (or trivalent) metal ions, such as calcium (Ca²⁺) and magnesium (Mg²⁺).

Uses

EDTA is used extensively in the laboratory to scavenge metal ions, for metal ion titrations, and in buffers. It is also used to determine water hardness and as a water softener.

EDTA is used in medicine as an anticoagulant, in the food industry as a preservative, and in lots of other stuff (even soaps, sun creme, etc). A somewhat controversial therapy, called chelation therapy has evolved around metal scavengers such as EDTA.