Nitrate nitrite

A nitrate nitrite, or nitrite nitrate, is a coordination complex or other chemical compound that contains both nitrite (NO−2) and nitrate (NO−3) anions. They are mixed-anion compounds, and they are mixed-valence compounds. Some have third anions. Many nitrite nitrate compounds are coordination complexes of cobalt. Such a substance was discovered by Wolcott Gibbs and Frederick Genth in 1857.^{[citation needed]}