Bond Angles

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305113590
Posts: 66
Joined: Fri Sep 28, 2018 12:28 am

Bond Angles

Postby 305113590 » Sun Nov 25, 2018 5:21 pm

Can someone tell me the bond angles for NO3- and S2O3^2-? I researched them and it says that the bond angles for NO3- is 120 and S2O3^2- is 109.5.
I thought bond angles change with double/triple bonds, but how come they aren't?
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Ryan Troutman 4L
Posts: 68
Joined: Fri Sep 28, 2018 12:22 am

Re: Bond Angles

Postby Ryan Troutman 4L » Sun Nov 25, 2018 5:35 pm

When you compare a single bond to a double bond, multiple bonds (double and triple) have a higher electron density region. If you think of it as a small circle, a single bond only has a small circle which can influence around it, and double bonds have a larger circle and a triple bond would be even larger. With the problem you're solving NO3- has a single double bond so it would make sense that the angle would be altered to be less than 120 degrees, but they could just state 120 because people interpret it that way. However, with the SO3-2 it seems as though the double bonds would influence the bond angles around it since it is tetrahedral. Perhaps since they are adjacent to one another the double bonds don't have any influence on one another and the bond angles would simply be 109.5.

305113590
Posts: 66
Joined: Fri Sep 28, 2018 12:28 am

Re: Bond Angles

Postby 305113590 » Sun Nov 25, 2018 7:07 pm

Ryan Troutman 3J wrote:When you compare a single bond to a double bond, multiple bonds (double and triple) have a higher electron density region. If you think of it as a small circle, a single bond only has a small circle which can influence around it, and double bonds have a larger circle and a triple bond would be even larger. With the problem you're solving NO3- has a single double bond so it would make sense that the angle would be altered to be less than 120 degrees, but they could just state 120 because people interpret it that way. However, with the SO3-2 it seems as though the double bonds would influence the bond angles around it since it is tetrahedral. Perhaps since they are adjacent to one another the double bonds don't have any influence on one another and the bond angles would simply be 109.5.


I feel the same way for both molecules. To add, I think that the NO3- as well has a resonance structure. Since electrons are delocalized, I thought this also contributed to it being 120.


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