Sodium monofluorophosphate, commonly abbreviated MFP, is the inorganic compound with the formula Na2PO3F. Typical for a salt, MFP is odourless, colourless, and water-soluble. This salt is an ingredient in some toothpastes. Sodium monofluorophosphate was first described in 1929 by the German chemist Willy Lange, who was then with the University of Berlin. His fruitless attempts to prepare the free monofluorophosphoric acid led him to check the stability of its esters. Together with Gerda von Krueger, one of his students, Lange thus synthesized diethyl fluorophosphate and some analogs, which proved to be quite toxic, being related to nerve agents. In the 1930s, Gerhard Schrader, working for the German company IG Farben, tried to develop synthetic insecticide. His work focused on esters of phosphoric acid and resulted in an accidental discovery of some other nerve agents such as DFP (diisopropyl fluorophosphate), Tabun, Soman, and Sarin.
MFP is prepared by hydrolysis of difluorophosphate ions with dilute sodium hydroxide:
PO2F2 + 2 NaOH = Na2PO3F + H2O + F
MFP is best known as an ingredient in toothpastes. It is claimed to protect tooth enamel from attack by bacteria that cause dental caries (cavities). It is also used to prevent oral plaque, oral bacteria and in treating gingivitis. MFP is also used in some medications for the treatment of osteoporosis.
Other applications include cleansing agent, disinfectant, metal surface treatment and fluorination of drinking water.