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When to use Expanded Octet?

Posted: Tue Nov 05, 2019 11:28 pm
by RRahimtoola1I
Are you supposed to use an expanded octet if you can make a Lewis Structure without it? For example, in ClO would I give Cl 9 electrons by making a double bond or leave it with 7 with a single bond even though the single bond gives Cl a -1 formal charge?

Re: When to use Expanded Octet?

Posted: Wed Nov 06, 2019 9:10 am
by Justin Sarquiz 2F
We should use the expanded octet in order to find the lowest energy Lewis structure. This means that we want the Lewis structure with the lowest formal charges. Therefore, it is crucial to solve for the formal charges whenever drawing Lewis structures because it shows whether the Lewis structure drawn is the most likely.

Re: When to use Expanded Octet?

Posted: Wed Nov 06, 2019 11:09 am
by Rory Simpson 2F
If you want to find the most stable Lewis structure, you would want to minimize formal charge and then use expanded octets if possible. Remember that expanded octets only apply for atoms in the 3rd period and after because they have d-orbitals available in their valence shell.