# Based on Molecular Orbital Theory , how is it decided that the double bond in O2 molecule has one sigma bond and one pi bond?

My Chemistry textbook says this in regard to a C2 molecule:

It is important to note that double bond in C2 consists of both pi bonds because of the presence of four electrons in two pi molecular orbitals.

Is it possible to account for the double bond in an Oxygen atom consisting of a sigma bond and a pi bond in the same way, based on MOT?

$$\ce{O2}$$ MO diagram
From the MO diagram, we can see that it has 2 electrons in a $$\sigma$$ orbital, 4 in $$\pi$$ orbitals, and 2 in $$\pi$$* orbitals. Taking this together gives a bond order 2, with 1 coming from the sigma electrons and another 1 being the net value for the $$\pi$$ and $$\pi$$* electrons.