Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: JohnTan on February 01, 2010, 06:21:57 AM
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Hi everyone, I'm just getting back into bonding and am getting puzzled by a few things. For instance, the sulfate ion SO4^-2. I understand that the structure has the sulfur atom as the center, with two oxygen atoms double bonded to this and the other two oxygen ions single bonded. However, I am also lead to believe that a double bond consists of TWO shared pairs of electrons. Taking this into account I cannot figure out what the molecule will look like in terms of lewis structure. The way I have drawn it shows only single bonds, with sulfur contributing two electrons in two of the bonds, and one electron from each being shared in the other two. I hope someone can help me with this, it will be much appreciated.
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Can you please post the structure that you have drawn?
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i'll try!
xx
xx O xx
- xx oo xx
xx O xo S xo O xx -
xx oo xx
xx O xx
xx
where x = oxygen electron and o = sulfur electron
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No, that's completely wrong..i actually have no idea now
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i'll try!
xx
xx O xx
- xx oo xx
xx O xo S xo O xx -
xx oo xx
xx O xx
xx
where x = oxygen electron and o = sulfur electron
What we have between the red oxygens and sulphur is a co-ordinate bond. Both the electrons are being donated by S. If you want to draw a double bond between 2 atoms, then 4 electrons need to be shared between 2 atoms.
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but if this is done, won't sulfur have too many electrons?
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Octet rule is not followed for all atoms.
See http://en.wikipedia.org/wiki/Expanded_octet
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that certainly throws a spanner in the works. thank you for your help
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No problem. :)