# With respect to C-C bonds, why is a double bond WEAKER than a triple bond?

May 4, 2017

You mean a $\text{double bond is weaker than a triple bond......}$

#### Explanation:

The modern chemical bond.........is CONCEIVED to be a region of high electron density between adjacent atoms such that internuclear repulsion is minimized (due to electrostatic interaction between like charges), and a net attractive force results between the electron cloud, and the positively charged nuclei.

And thus, for single bonds, we say that the electrons are shared between each nuclei:

When we introduce multiple bonding, the bonding pairs of electrons are conceived to lie in planes above and below the $\text{atom"-"atom}$ vector.......

In the representation of the ethylene molecule, there are 4 bonding electrons, and this degree of electron density allows closer approach of the bound carbon atoms. A $C - C$ single bond has an approx. bond length of $1.54 \times {10}^{-} 10 \cdot m$. A $C = C$ double bond has an approx. bond length of $1.35 \times {10}^{-} 10 \cdot m$. And a $C \equiv C$ triple bond has an approx. bond length of $1.20 \times {10}^{-} 10 \cdot m$:

The degree of bonding interaction is not linear. Also see this answer.