acid and the like and mixtures thereof exemplary aminophosphonates include for example compounds having a methyl phosphonic acid or alkali metal or ammonium salt thereof bonded to a nitrogen atom such compounds can be generally described by the formula wherein m is hydrogen nh 4 alkali metal or a combination thereof and n is 1 2 or 3 other exemplary aminophosphates include without limitation amino tri lower alkyidenephosphonic acids or their water soluble salts as defined by the formula wherein x and y represent hydrogen or lower alkyl having 1 to 4 carbon atoms illustrative compounds include amino tri methylphosphonic acid n ch 2 p o oh 2 3 amino triethylidenephosphonic acid n ch 3 chp o oh 2 3 amino tri isopropylidenephosphonic acid n ch 3 ch 3 cp o oh 2 3 and the like and mixtures thereof exemplary acylation products of phosphorous acid include for example compounds of the formula wherein r is alkyl having 1 to 5 carbon atoms alkali metal ammonium and ethanolamine salts thereof and mono and dialkyl esters thereof with methanol ethanol propanol or butanol exemplary phosphonates include but are not limited to 2 hydroxy phosphonoacetic acid hpa tris amino phosphonic acid amp 1 1 hydroxyethylidine diphosphonic acid hedp ethylene diamine tetra methylenephosphonic acid entp hexamethylene diamine tetra methylenephosphonic acid hmtp diethylene triamine penta methylenephosphonic acid 2 phosphono 1 2 4 butanetricarboxylic acid pbtc and the like and mixtures thereof these and other phosphonates are well known in the art and are described in.