Bond Angles

[Emily_Stenzler_2H]

I think I am missing something conceptual here, but why do bond angles, such as the 3 106 degree bond angles on SO3^2- , not add up to 360? If they are evenly spaced around the S atom wouldn't the angles need to add up to 360 degrees?

[Kiara Phillips 3L]

From my understanding, the angles mark the distance between one oxygen, back to the sodium molecule and back out to the next oxygen. I believe that the reason the distance does not add up to 360 degrees is because the oxygen molecules themselves occupy space within the "circle" of the compound. So in that case, the angles could never add up to be exactly 360 degrees because there are molecules there that are taking up that space in the "circle" I hope this helps!

[Juwon Lim 2A]

The 3 bond angles would add up to 360 if the geometry of the molecule was trigonal planar. This is because, on a flat circle, the angles should add up to 360. However, SO3^2- has a lone pair making the shape tetrahedral. Then, the 360 rule does not apply since the shape is 3 dimensional.

[Kiyoka Kim 3C]

The angles depend on whether the atoms are all in the same place or not. For instance, in the tetrahedral geometry the atoms are not in the same place so the angles would not add up to 360º. While in the trigonal planar geometry they are so the bond angles would add up to 360º.

[Taber Ball 1F]

I think I am missing something conceptual here, but why do bond angles, such as the 3 106 degree bond angles on SO3^2- , not add up to 360? If they are evenly spaced around the S atom wouldn't the angles need to add up to 360 degrees?

Hi! The angles do not add up to 360º because the molecule is three dimensional. If the molecule were trigonal planar (on a flat circle) then the angles would add up to 360º. This, however, is not the case because there is a lone pair making the shape tetrahedral (3-D). Hope this helps!

[America Ramirez 3H]

I think it all depends on how many planes the molecule takes up.