Resonance Structures

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Eunice Lee 1A
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Joined: Wed Oct 03, 2018 12:16 am

Resonance Structures

Postby Eunice Lee 1A » Tue Nov 06, 2018 10:18 am

How do resonance structures affect bond length?

Posts: 64
Joined: Fri Sep 28, 2018 12:17 am

Re: Resonance Structures

Postby taline_n » Tue Nov 06, 2018 10:36 am

Bond lengths are averaged in resonance hybrids; whether it's a single bond or double bond, the average between them is the number used for bond length in the molecule as a whole.

Ava Kjos 1D
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Joined: Fri Sep 28, 2018 12:19 am

Re: Resonance Structures

Postby Ava Kjos 1D » Tue Nov 06, 2018 11:57 am

To expand on that, if there is only one resonance structure, the bond lengths will be exactly the length of a single bond or a double bond, depending on what kind of bond it is. However, if there are multiple resonance structures, the bond length will be somewhere in between the length of a single bond and a double bond because it will be a hybrid of both.

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Re: Resonance Structures

Postby MaggieMatern_Dis1H » Tue Nov 06, 2018 5:37 pm

Resonance structures are characterized by the difference in location of a bond (in this picture, the double bond in the molecule NO3-).
Since there is a double bond, the bond length of the N-O bonds will be shorter than that of a 'regular' single bond of N-O.

Therefore, resonance structure bond lengths will usually be between the bond lengths of a single and double bond of the elements in question.

Searra Harding 4I
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Re: Resonance Structures

Postby Searra Harding 4I » Wed Nov 07, 2018 12:37 am

If you are asked which structure has a longer bond length and both have double bonds, then check how many resonance structures each has. If one has four resonance structures and the other only has two, then you know the one with four resonance structures has longer bond lengths.

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