[chemical substances]
   compounds
     Class hydrazides [RkE(=O)l(OH)m (l≠0; ≥1 (OH):=(=NRNR2))]
       1 Class carbohydrazides [RC(=O)NHNH2]
       2 Class sulfonohydrazides [RS(=O)2NHNH2]
       3 Class phosphonic dihydrazides [RP(=O)(NHNH2)2]