Nitrosonium

The nitrosonium ion is NO⁺, in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. This ion is usually obtained as the following salts: NOClO₄, NOSO₄H (nitrosylsulfuric acid, more descriptively written ONSO₃OH), and NOBF₄. The ClO−
4 and BF−
4 salts are slightly soluble in CH₃CN. NOBF₄ can be purified by sublimation at 200–250 °C and 0.01 mmHg (1.3 Pa).

NO⁺ is isoelectronic with CO, CN^- and N₂. It arises via protonation of nitrous acid:

Chemical Properties

Hydrolysis

NO⁺ reacts readily with water to form nitrous acid:

For this reason, NOBF₄ must be protected from water or even moist air. With base, the reaction generates nitrite:

As a diazotizing agent

NO⁺ reacts with aryl amines, ArNH₂, to give diazonium salts, ArN+
2. The resulting diazonium group is easily displaced (unlike the amino group) by a variety of nucleophiles.

As an oxidizing agent

NO⁺, e.g. as NOBF₄, is a strong oxidizing agent: