[Capital]

Using the molecular bond theory, the MO configuration for carbon is σ2s^2, σ*2s^2, pi2p^4

The bond order is then (4+2-2)/2 = 2. (double bond)

I thought when there is a double bond, there is always one sigma and one pi bond but why are both bonds in diatomic carbon pi?

I'm specifically wondering why the p orbitals would produce two pi bonds instead of a sigma and a pi bond. Why are the p orbitals sideways overlapped?