Silver nitrite, AgNO₂

Sodium nitrite and the corresponding salts of potassium and barium react with Silver nitrate to form Silver nitrite, AgNO₂. It crystallizes in long, greenish-yellow, rhombic needles, the density at 0° C. being 4.542, and between 21° and 31° C. 4.453. At 15° C. its percentage-solubility is 0.2752, and at 18° C. 0.0216 gram-molecules dissolve in 1 litre of water.

In the moist condition the salt is readily reduced by organic matter. When heated rapidly in vacuo, it is completely decomposed into silver and nitrogen peroxide. Slower heating in air causes side-reactions in accordance with the equations

Ag + 2NO₂ = AgNO₃ + NO;
AgNO₂ + NO₂ = AgNO₃ + NO.

Several double salts with alkali-metal nitrites have been described. Double compounds with ammonia of the formulae AgNO₂,NH₃; AgNO₂,2NH₃; and AgNO₂,3NH₃ have also been prepared. A double salt with caesium, AgCs(NO₂)₂, is formed by the interaction of caesium nitrite and silver nitrite. It crystallizes in lemon-yellow needles.