Nitrous oxide, molecular model. The chemical formula is N2O, with the atoms (spheres) colour-coded: nitrogen (blue) and oxygen (red). Also known as laughing gas, this chemical is used in surgery as a analgesic and anaesthetic drug. It is also used as an oxidizer in rocket motors and combustion engines. The bond lengths are given at bottom in picometres (pm). The nitrogen-nitrogen bond is 118.6 pm, while the nitrogen-oxygen bond is 112.6 pm.