2373-43-5 4-16-00-01081 (Beilstein Handbook Reference) AI3-19127 BRN 2941121 Benzenephosphonic acid, p-chloro-, diethyl ester Phosphonic acid, (4-chlorophenyl)-, diethyl ester Phosphonic acid, (p-chlorophenyl)-, diethyl ester p-Chlorophenyl diethoxy phosphine oxide