Tuesday, February 8, 2011

Feather Touch = Detonation?

Nitrogen triiodide (NI3) is a compound well known for its infamous instability. This compound is quite stable when it is wet but the same thing cannot be said when it is dry. The readiness to decompose of dry nitrogen triiodide is something to be respected. As a matter of fact, in order to trigger nitrogen triiodide’s decomposition, all it takes a light brush of a feather. More interestingly, a pile of NI3 can go off by itself due to its own weight. However, what makes nitrogen triiodide a very potent explosive is that even though NI3 itself is a solid, it produces two gases after its decomposition, N2 and I2, which immediately and rapidly expand and take up much more space than the original compound.

Some explanations for NI3’s ridiculous instability: In NI3 structure, the central N atom is surrounded by three I atoms. Although I is a halogen, its electronegativity is small because of its large atomic radius; therefore, the three N-I bonds are weak. These weak bonds are the first to be responsible for NI3’s instability. Also, each I atom in a NI3 molecule has a tendency of repelling one another due to its massive electron cloud, so the three I atoms want to stay spread out as much as possible. However, they are unable to; the reason is that the central N atom has a lone pairs of electrons which forces them to stay close together.  

Some videos about people detonating nitrogen triiodide:
WARNING: These videos are to be watched not followed. Any attempt, especially failed one, is highly discouraged.
http://www.youtube.com/watch?v=2KlAf936E90
http://www.youtube.com/watch?v=-FcVuYuFx6o&feature=related
http://www.youtube.com/watch?v=Yr4GgzVlmmw&has_verified=1 (This video is marked as *inappropriate* and requires signing in because it shows the whole process of home-madely synthesizing NI3.)



Posted by Chinh Ngo

No comments:

Post a Comment