Nitrous Oxide (Nâ‚‚O) is commonly known as ‘laughing gas’ or sweet air. It is a chemical compound – an oxide of Nitrogen. At room temperature, it is a colourless, non-flammable gas, with a slightly sweet odour and taste. It is used in surgery and dentistry for its anaesthetic and analgesic effects. It is known as laughing gas due to the euphoric effects of inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. At elevated temperatures, Nitrous Oxide is a powerful oxidiser similar to molecular Oxygen.