Hydrazinium azide

Hydrazinium azide or hydrazine azide is a chemical compound with formula or. It is a salt of the hydrazinium cation and the azide anion. It can be seen as a derivative of hydrazine and hydrazoic acid. It is an unstable solid.
When very pure, it is insensitive to ordinary levels of shock or impact and only decomposes slowly when heated, but less pure forms tend to explode when heated to a bit over or when heated too rapidly.

Structure

The solid undergoes structural phase transition to a different crystalline arrangement at a pressure of.

Hydrazinium azide was first prepared by neutralizing hydrazoic acid with hydrazine hydrate.

Hydrazinium azide decomposes explosively into hydrazine, ammonia, and nitrogen gas:
Crystallization with an equimolar amount hydrazine yields the solid hydrazinium azide hydrazinate,, or, as monoclinic crystals. This compound is less hygroscopic and less volatile than pure hydrazinium azide. It decomposes explosively into nitrogen, hydrogen, and ammonia.
At pressure of, hydrazinium azide decomposes yielding a linear nitrogen allotrope or, that decomposes to [ε-N2|] below.
Reaction of hydrazinium azide with sulfuric acid gives quantitative yields of pure hydrazinediium sulfate and hydrazoic acid: