Peroxynitrate (or peroxonitrate) refers to salts of the unstable peroxynitric acid, HNO4.

Peroxynitrate is unstable and decomposes to nitrate and dioxygen.

[1] No solid peroxynitrate salts are known.

[2] However, there is a report that the chemist Sebastian Moiseevich Tanatar produced sodium peroxynitrate octahydrate (NaNO3·H2O2·8H2O) by evaporating a solution of sodium nitrate and hydrogen peroxide until crystallisation begins and then mixing with alcohol to form crystals of the octahydrate.

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