Typpi

Typpi, known in English as nitrogen (symbol N, atomic number 7), is a nonmetal that makes up about 78% of Earth's atmosphere. In its diatomic form, N2, it is a colorless, odorless gas. The strong triple bond makes N2 relatively inert at ambient conditions, though it participates in chemical reactions under suitable catalysts or energy input. Liquid nitrogen (-196°C) is widely used as a cryogenic coolant.

In biology, nitrogen is essential for all living organisms because it is a key element of amino acids, nucleic acids, and many cofactors. Most organisms rely on a nitrogen cycle that includes fixation of atmospheric N2 into reactive forms by bacteria and archaea, assimilation by plants, mineralization (ammonification), nitrification, and denitrification, returning N2 to the atmosphere.

Industrial production of fixed nitrogen is dominated by the Haber-Bosch process, which combines N2 with hydrogen to produce ammonia (NH3) under high temperature and pressure using iron catalysts. Ammonia and its derivatives (such as ammonium salts and urea) are major components of agricultural fertilizers, which vastly increased crop yields. Nitrogen compounds have other uses in metallurgy, electronics, food packaging, and cryogenics.

In Finnish, the element is called typpi. Its properties and cycles are central to environmental science, agriculture, and chemistry.