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Most Favorable Placement of Formal Charges

Posted: Mon Nov 26, 2018 9:27 pm
by annabel 2A
is it more favorable to have formal charges spread out or to have them concentrated? For example, for N3- is it more favorable for one of the formal charges to be [2-, 1+, 0] or [1-, 1+, 1-]? or are neither of them the best one?

Re: Most Favorable Placement of Formal Charges

Posted: Mon Nov 26, 2018 9:29 pm
by Ronald Thompson 1F
I believe for the purposes of this class the spread of the charges doesn't quite matter. I do not recall coming across a problem where the two possibilities have the same formal charge.

Re: Most Favorable Placement of Formal Charges

Posted: Mon Nov 26, 2018 9:44 pm
by Danielle_Gallandt3I
It depends on the situation. It is better to have them concentrated if one molecule is much more electronegative than the other, because it would not make sense for electrons to be more electrostatically attracted to something like hydrogen over something like oxygen. Another thing to consider,, however, is that you typically want the lowest average formal charge, in which case (+1, 0, -1) makes more sense. This is not a hard and fast rule though, because a lot of the placement of electrons is dependent on the atoms within each molecule and their specific characteristics.