About 78% of our atmosphere is dinitrogen, also called molecular nitrogen (N2).
Because each pair of nitrogen atoms bound together with triple bonds,
dinitrogen is inert.
All living organisms depend on atomic nitrogen,
but to make it useful biologically, dinitrogen must be split.
The energy it takes to split dinitrogen is released when the separate atoms are allowed to recombine,
which makes nitrogen useful for propellants and explosives.
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