Stability of molecules?
The N2 molecule is considered inert and very stable because of its high bonding energy (941 KJ/mol). It takes that much of energy to break the bonds apart. At the same time, benzene is also considered to be stable because of it´s low energy, due to delocalized electrones. Since the bonds contains relatively small energy, the should also be easy to break and hence the molecule isn´t that stable? Please help me...
- MefLv 51 decade agoFavorite Answer
Stability is relative. Yes, nitrogen is very stable, and yes, compared to nitrogen, bezene isn't that stable. However, in general we are not comparing benzene to nitrogen, we are comparing benzene to other similar organic molecules. There are only a select number of reactions that can be performed on benzene. One reason for this is that it radially symmetric (due to those delocalized electrons). If you think about it, to have a chemical reaction you need to restructure the bonds in a molecule, that means you have to break some of the bonds, and then reform them. With something like benzene though, it's likely that if you have something that can break one of the bonds, it will be able to break any and all of them (they're all basically the same, remember?). This means that if you aren't careful, you'll just end up burning it (that is, breaking all of the bonds).
Look at cyclooctatetraene. It has 8 carbons in a ring, and just like benzene it alternates double bonds and single bonds all the way around. Unlike benzene though it doesn't have the same delocalization and is not aromatic, so there are quite a few chemical reactions you can perform on it that you cannot perform on benzene. In this sense, benzene is relatively stable. In fact if you look at most organic molecules that have multiple double bonds (they're called poly-enes) you can find entire sets of reactions available that will not work with benzene, due to its added stability.
- Anonymous5 years ago
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to determine the stability of the molecule, you need to look at the structure (so the VESPR shapes), the polarity of the bonds and molecules. so like, PCl3: it's vespr shape is based on tetrahedral, and so it is trigonal pyramidal with one lone pair. then u check the delta EN between the P and the Cl which is 0.97, that means there is a partial negative charge on each Cl. therefore, the overall polarity of the molecule is polar with the negative directed towards the chlorine (so down- depends on how you draw it). so PCl3 is relatively stable however due to the molecular polarity, is can be attracted to other polar molecules resulting in reactions. If it was put in water, it would diassociate into ions. You also need to look at the molecule's solubility. Factors determining stability of the molecule varies from substance to substance, especially if it's inorganic or organic... because then there are many other factors you need to think about. I hope this helps. There may be plenty more factors that one can consider that I may not have mentioned, so maybe some research might help.
- 1 decade ago
you are asking about diatomic molecules whose stability depends on 1) more bond energy 2) high bond order 3) electrons should not present in anti bonding molecular orbital 4) should be diamagnetic. which is available in N2. but in benzine its stability depends on 1) more resonance energy 2) huckels rule is obeyedSource(s): phycal chemistry by Dr O P Tondon