Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: ReVeR on December 28, 2005, 09:31:27 PM
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Hello.
I was wondering why a polyatomic ion Cn has a charge of negative 1.. i mean does it randomle get 1 extra electron or why?
Thx
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Yes, actually. The CN ion grabs an electron from something like a metal or hydrogen to get that negative charge. That's why CN doesn't really exist, but NaCN, LiCN, KCN, RbCN, CsCN, HCN, etc. do exist. The metal/hydrogen donates its electron to the CN ion forming M+CN-.
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That's why CN doesn't really exist
Correct! But there is a compound that has the formula (CN)2, it is called "cyanogen" :)
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I posted this information not long ago. CN- is isoelectronic with very stable particle - N2.
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what does the mean? the isoelectronic with N2?
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It has identical orbitals and identical number of electrons. N2 is very stable particle, which means that its structure (in terms of electrons/orbitals) has very low energy. If you remove one proton you have an ion CN- - it is less stable, but 'inherits' some of its stability from the N2.
Note that this stability is present also in nitrosonium ion (NO+) - here we add one proton to particle. Nitrosonium is stable enough to allow preparation of salts - like nitrosonium perchlorate. But that's rather exotic particle.