2012-00-2 4-16-00-01070 (Beilstein Handbook Reference) BRN 2949526 CCRIS 7776 Epn oxon O-Ethyl O-4-nitrophenyl phenylphosphonate O-Ethyl O-p-nitrophenyl phenylphosphonate Phosphonic acid, phenyl-, ethyl 4-nitrophenyl ester