HMPA cas:680-31-9 Hexamethylphosphoramide High Quality High Content Name ... ,N,N,N,N-Hexamethylphosphoric triamide; Tris(dimethylamino)phosphine oxide; HMPA Molecular Structure Molecular Formula C6H18N3OPMolecular Weight 179.20CAS Registry Number ... Symbols T Risk Codes R45;R46 Safety Description S53;S45 HMPA cas:680-31-9 Hexamethylphosphoramide