form a weaker π bond. It is weaker because the overlap is not end-to-end but only side-to-side. You
can see this by rotating the molecule 90° out of the paper so that the plane of the molecule is now
coming out at you:
A single bond then consists of one σ bond, while a double bond consists of a σ and a π bond. Since,
as just mentioned, a π bond is weaker, a double bond is not twice as strong as a single bond, even
though it is stronger because of the additional interactions.
Similarly, a triple bond consists of a σ and two π bonds: in the sp hybridization scheme, two p
orbitals are left unused, one along the x and one along the y direction. Each of these can form a π
bond with a parallel p orbital on a neighboring atom. These, together with the σ bond along the z
direction formed from the end-on-end overlap of two sp hybridized orbitals, give three bonds total.
Again, since π bonds are weaker, a triple bond, though stronger than a single bond, is not three
times as strong.
DON’T MIX THESE UP ON TEST DAY
THINGS TO REMEMBER
A single bond consists of one σ bond.
A double bond consists of a σ and a π bond.
A triple bond consists of a σ and two π bonds.Ionic Bonds