Earth’s atmosphere is 78.09% nitrogen in its diatomic form
(N2), in which pairs of nitrogen atoms are joined by an
extremely strong bond. All living organisms require nitrogen in
their DNA and RNA; all green plants require nitrogen as a primary
nutrient. About 3% of the human body is nitrogen.
After diatomic nitrogen is broken, it can be combined with other
elements into many useful forms, including ammonia (NH3),
nitrate (NO3) used for artificial fertilizers, nitric
acid (HNO3), nitroglycerin used for explosives such as
dynamite, and cyanides (which include a nitrogen atom
triple-bonded to a carbon). When these compounds decompose back to
nitrogen gas, they release large amounts of energy, and can,
Rhizobia are not the only miracles of nature that fix
nitrogen. Some non-legumes have nitrogen-fixing symbiotic
associations with cyanobacteria or Frankia bacteria. All natural
nitrogen-fixing processes use an enzyme complex named nitrogenase.
Also, there are industrial processes to create ammonia and other
nitrogen compounds including a process based on a method used by
Henry Cavendish in 1784.
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