A nitrogen bomb typically refers to an explosive device made from compounds that contain less stable formations of nitrogen that release tremendous energy once the required level of activation energy is released, causing an explosion. Bombs utilizing nitrogen include C4, nitroglycerin, TNT and the infamous fertilizer bomb of Timothy McVeigh.
The Earth's atmosphere is made up of roughly 80 percent nitrogen, but this version is the stable triple-bonded nitrogen gas (N2) that requires temperatures of up to 1,000 degrees Celsius to break. Nitrogen bombs exert enough activation energy to cause unstable nitrogen-based compounds like ammonium nitrate to break apart and form atmospheric nitrogen. Both the breaking and forming of N2's triple bond release vast quantities of energy that can be very destructive. The nitrogen's change from a solid to a gas causes a rapid expansion, creating a destructive shock wave.