NH2NH3

NH2NH3 typically refers to the hydrazinium cation, often written as [N2H5]+. It is the conjugate acid of hydrazine (N2H4) formed by protonation and occurs in the form of hydrazinium salts such as hydrazinium chloride, hydrazinium sulfate, and related salts. In solution and in salts, the cation carries a positive charge and is paired with various anions.

Structure and bonding: the hydrazinium cation consists of two nitrogen atoms joined by a single N–N bond. One nitrogen bears three hydrogens (NH3) and a formal positive charge, while the other bears two hydrogens (NH2) and a lone pair. The geometry around the nitrogens is approximately pyramidal due to lone pairs. The N–N bond length is typical for a single N–N bond in such cations.

Preparation and occurrence: hydrazinium salts are prepared by protonating hydrazine with strong acids. They are common in inorganic and coordination chemistry as sources of the hydrazinium cation in various metal salts and ionic compounds.

Reactions and uses: hydrazinium salts are used as reagents in organic synthesis and as sources of hydrazine under certain conditions. They can act as precursors to hydrazine in situ or participate in coordination chemistry with metal centers. Safety is a consideration, as hydrazinium compounds are typically toxic and can be reactive, especially upon heating or perturbation.

See also: hydrazine, ammonium salts, ionic compounds.