Nitrogen is an abundant chemical element that exists in the atmosphere as a diatomic molecule where two atoms of Nitrogen share 3 pairs of electrons in a triple bond. Nitrogen makes up 78% of the atmosphere and is breathed in and exhaled by humans but is not taken into the human body. Despite this, Nitrogen is a vital component in construction of proteins, amino acids and DNA. It is especially important in plant development and exists in soil as the compound Ammonia. Nitrogen is widely used in the creation of Ammonia in the Haber process as a fertiliser and is used to make explosives such as TNT. Nitrogen was discovered in 1772 by the physician Daniel Rutherford but has been known as a compound in nitric acid and ammonia since the middle ages. It is located in Group 15. It is a non metal gas at room temperature and it has a melting point of -210°c and a boiling point of -195°c. Whilst inert when breathed in by humans Nitrogen poses several risks to divers through Nitrogen Narcosis and the Bends. Nitrogen bubbles created in human tissue expands when divers ascend to the surface making it dangerous to ascend to quickly or spend too much time underwater.