# Molecular Orbital Theory and No. of bonds

The order of filling of molecular orbitals $\ce{O2}$ by MOT is this :

But from it, how can I deduce that there is one sigma and one pi bond in an oxygen molecule ?

• If I am not mistaken, the $2\sigma_g$ should be higher in energy than $\pi_u^x,\pi_u^y$. – Martin - マーチン Nov 18 '14 at 13:06
• @martin That's for molecules having electrons less than or equal to 14 , like nitrogen – biogirl Nov 18 '14 at 16:26