Nitrous oxide (also known as laughing gas) is an oxide of nitrogen with the formula N2O. At room temperature, it is a colorless non-flammable gas, with a slight metallic scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen.

Nitrous oxide is mostly used in the high-tech thin film industries of semiconductor and LCD display manufacturing, and for medical applications (anaesthetics). N2O is aslo a food and beverage propellant additive (for whipped cream, for example), an industrial propellant and foaming agent, and a fuel oxidiser for rockets and race cars.