atmospheric nitrogen exists in the form of two atoms fused together in an incredibly tight bond; breaking these atoms apart and forming them into other nitrogen compounds we can use—“fixing,” as it’s usually called—involves phenomenal amounts of heat and energy. This also, by the way, helps explain why fixed nitrogen is at the heart of most explosives: just as it takes a lot of energy to break that atmospheric nitrogen apart, you generate a lot of energy when you put it back together.
