What is "phosphonate"

n. (context chemistry English) Any salt or ester of a phosphonic acid; many of its derivatives have important biological activity.

Phosphonates and phosphonic acids are organophosphorus compounds containing C−PO(OH) or C−PO(OR) groups (where R = alkyl, aryl). Phosphonic acids and phosphonate salts are typically white, nonvolatile solids that are poorly soluble in organic solvents, but soluble in water and common alcohols. Many commercially important compounds are phosphonates, including glyphosate, the herbicide "Roundup", and ethephon, a widely used plant growth regulator. Bisphosphonates are popular drugs for treatment of osteoporosis.