Bond Length of Single Bond, Double Bond, and Tripler Bond.

[Mulin_Li_2J]

Can anyone tell me why would a double bond be shorter than a single bond? I know double bond has higher electron density than single bond, but doesn't high electron density means high repulsion forces among electrons and thus a longer bond length?

[Sarah Blake-2I]

A double bond is stronger than a single bond which would make the bond length shorter than a weaker single bond. For triple bonds, the same idea applies in which the triple bond is stronger than the double bond and even stronger than the single bond, which makes the triple bond the shortest out of those three bonds.

[Sydney Pell 2E]

A double bond is shorter than a single bond because although there are more electrons that would want to repulse each other, the electrostatic pull between the positive nuclei and the now more negatively charged (with 2 electrons shared instead of 1) double bond will overcome this. The pull between the nuclei of the two atoms and the electrons between them will be greater because there is a stronger negative charge to attract the positive charges, meaning the atoms are pulled closer together and the bond is stronger.