# How do I draw the MO diagrams for #"O"_2^-# and #"CO"^(+)# and find out which one is paramagnetic?

##### 1 Answer

Well, the MO diagrams for

- For
#ul("O"_2^(-))# , just take the MO diagram of#"O"_2# and add one electron into the#pi_(2px)^"*"# antibonding molecular orbital. - For
#ul("CO"^(+))# , just take out one of the electrons from the#3sigma# HOMO from the MO diagram of#"CO"# .

Both substances are **paramagnetic**, as they have at least one unpaired electron in a given orbital.

The unpaired electron orients itself in the direction of an applied magnetic field, and gives rise to a **total magnetic moment**

- the total electron spin
#S = |sum_i m_(s,i)|# - the total orbital angular momentum
#L = |sum_i m_(l,i)|#

for the

*The total magnetic moment is a value that can be obtained experimentally from magnetic susceptibility measurements.*