Nitrous oxide, commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula N2O.
At room temperature, it is a colourless non-flammable gas, with a slight metallic scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen.
Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anaesthetic and pain reducing effects. Its colloquial name, “laughing gas”, coined by Humphry Davy, is due to the euphoric effects upon inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is on the World Health Organisation’s List of Essential Medicines, the safest and most effective medicines needed in a health system. It is also used as an oxidiser in rocket propellants, and in motor racing to increase the power output of engines.