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Topic: Nitrogen reaction with Alkali Metals  (Read 7203 times)

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Offline Controlled Substance

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Nitrogen reaction with Alkali Metals
« on: April 16, 2008, 11:55:21 AM »
Mornin',

I was reading about ionic bonds and main-group chemistry this morning and one thing struck my attention.

Apparently, lithium is the only one of the alkali metals that can react with nitrogen gas. Wikipedia adds that lithium nitride is the only stable alkali metal nitride.

Observing that lithium has the highest first ionization energy and is the least reactive of the group, I am really wondering why this is so.

The only thing that comes to mind is that the Lattice energy of other compounds such as Na3N and K3N is greatly reduced so the reaction is now endothermic.

Am I on the right track or are there more factors that come into play? I'd ask my teacher, but I'm too cool for school until I get back into college ;D

Offline Controlled Substance

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Re: Nitrogen reaction with Alkali Metals
« Reply #1 on: April 16, 2008, 12:07:51 PM »
Na3N synthesized from its elements by low-temperature technique:
http://pubs.acs.org/cen/topstory/8020/8020notw9.html

umm... cool?   :o

Online AWK

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Re: Nitrogen reaction with Alkali Metals
« Reply #2 on: April 16, 2008, 12:10:09 PM »
In fact, lithium reacts with air to form both Li2O and LiN3 but I do not know a theoretical explanation. Note, also some rare transition metals also react with nitrogen, but this time form a dinitrogen complex instead of ionic bond

Corrected - must be Li3N - lithium nitride
« Last Edit: April 17, 2008, 12:57:15 AM by AWK »
AWK

Offline Controlled Substance

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Re: Nitrogen reaction with Alkali Metals
« Reply #3 on: April 16, 2008, 01:54:44 PM »
Thanks for your reply.

I'm sure you meant Li3N Litium Nitride not LiN3 Lithium Azide?
If not I'm moar confused... hehe.

I got the feeling I've asked something which may be out of my scope...

But seeing as how Lattice Energy is inversely proportional to the ionic radii of the ions involved; I think I answered my own question... Li+F- has higher bond strength than Na+F- for example...

I couldn't do any calculations to prove to myself that other alkali metal nitrides cannot be produced by conventional methods because I am missing information.

I still feel like I'm missing something.

Any more comments will be appreciated.


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