In: Chemistry
What is the resonance structure for SeO2 and how is the bond lenght compared to an isolated single or double bond?
The bonding electrons draw the atoms closer together but as the atoms get very close they experience repulsive forces from the other non-bonding electrons and from the two nuclei themselves.
This means that there is an optimum distance for the two atoms.
Although it is difficult to make a direct relationship between bond length and strength there are some inferences that can be obtained. It can be seen that as the bond length of the carbon - halogen bonds increases so the bond energy decreases. As the atoms get larger they are held further apart by inter-electron repulsions. The attractive force between the bonding electron pair and the nuclei is consequently weaker.
As the bond strength INcreases, so the bond length DEcreases. This follows from a consideration of the force of attraction between the greater number of pairs of electrons and the two nuclei. Four electrons (two pairs) can pull the two nuclei closer together than two electrons (one pair).
Now for SeO2 the resonance structures: