lämmastik

lämmastik is the chemical element with symbol N and atomic number 7. It is a nonmetal that in standard conditions exists predominantly as diatomic molecule N2, which makes up about 78% of Earth's atmosphere. N2 is colorless, odorless, and highly inert due to its triple bond, with a boiling point of −195.8 °C and a melting point of −210 °C.

In nature, nitrogen occurs mainly as N2 in the atmosphere and in reactive forms such as ammonia (NH3), nitrates (NO3−) and ammonium (NH4+) in soils and organisms. Most biological nitrogen is obtained through fixation by bacteria, cyanobacteria, and abiotic processes that convert N2 into biologically usable compounds. The element is essential for all living organisms; it is a constituent of amino acids, proteins, nucleic acids, and chlorophyll.

Industrial production: The Haber-Bosch process combines N2 with hydrogen to produce ammonia (NH3), a key raw material for fertilizers and various chemicals. Nitrogen compounds are used in explosives, manufacturing, refrigeration, and pH control. The most common nitrogen isotopes are 14N and 15N, with 14N about 99.6% of natural nitrogen.

Environmental and safety: Nitrogen gas itself is non-toxic but in confined spaces can cause asphyxiation. Excessive reactive forms like nitrates can contribute to eutrophication and water pollution; some nitrogen compounds are toxic or oxidizers.

History: Daniel Rutherford described "noxious air" in 1772 as a distinction from real air, isolating nitrogen. In Estonian, the element is called lämmastik.