Overview

Nitric oxide (NYE-trik OK-side) is a sweet-smelling, colorless gas that can be liquefied to make a bluish liquid and frozen to produce a bluish-white snow-like solid. It is one of five oxides of nitrogen, the others being nitrous oxide (N₂O), nitric oxide (NO), dinitrogen trioxide N₂O₃), and nitrogen dioxide (NO₂). Nitric oxide was first discovered in 1620 by Flemish physician and alchemist Jan Baptista van Helmont (1580–1635 or 1644).

Nitric oxide is used in the production of nitric acid, ammonia, and other nitrogen-containing compounds. It is also formed as a byproduct of the combustion of coal and petroleum products. As such, it is a major contributor to air pollution.

Key Facts

Other Names:

Nitrogen monoxide

Formula:

NO

Elements:

Nitrogen, oxygen

Compound Type:

Nonmetallic oxide (inorganic)

State:

Gas

Molecular Weight:

36.01 g/mol

Melting Point:

−163.6°C (−262.5°F)

Boiling Point:

−151.74°C (−241.13°F)

Solubility:

Slightly soluble in water

How It Is Made