H3NNH2

H3NNH2 is a chemical notation that denotes a two-nitrogen, five-hydrogen species with formula N2H5. In a simple line-bond view it would be drawn as H3N–NH2, implying a single N–N bond with one nitrogen bearing three hydrogens and the other bearing two. If drawn this way, the more protonated nitrogen would carry a formal positive charge, so the neutral form H3NNH2 does not correspond to a stable isolated molecule in standard conditions. In practice, the stoichiometry N2H5 is most commonly encountered in the hydrazinium unit [N2H5]+ found in salts, rather than as a neutral molecule.

Relation to hydrazine and hydrazinium: Hydrazine has the formula N2H4. Protonation of hydrazine yields the hydrazinium cation [N2H5]+, which is a well-characterized species in aqueous and solid-state chemistry. The neutral N2H5 species, if considered, would be highly reactive and has primarily appeared in theoretical studies or high-energy gas-phase contexts as a transient radical or as part of computational explorations of nitrogen-hydrogen bonding.

Synthesis and occurrence: Hydrazinium salts are produced by protonating hydrazine, for example in acid solutions, to form salts such as hydrazinium chloride. The hypothetical neutral N2H5 molecule is not routinely prepared or observed under normal laboratory conditions.

Safety: Hydrazine and its derivatives are toxic and potentially carcinogenic; hydrazinium salts can be strong oxidizers and hazardous. Appropriate handling, ventilation, and protective equipment are essential in any work involving nitrogen hydrides.

See also: hydrazine, hydrazinium, nitrogen-hydrogen compounds.