Phosphonic /(fŏs*fŏn"ĭk)/

Phos·phon·ic

Phosphonic

a.
  1. Pertaining to, or designating, certain derivatives of phosphorous acid containing a hydrocarbon radical with the phosphorus directly bonded to a carbon, and analogous to the sulphonic acids; as, methanephosphonic acid, CH3.PO.(OH)2. (Chem.)