is O2 paramagnetic ?

Question

it is written on my book paramagnetic but it should be diamagneticas i guess is it true ?if wrong please explain why ?

Answer 1

It is paramagnetic. Unfortunately it isn't evident from simple Lewis structures, but it is evident from molecular orbital theory. A picture is really worth a thousand words here, but here's an attempt. Since oxygen has 6 valence electrons, O2 has 12 electrons to account for. Each oxygen contributes four atomic orbitals (an s and three p orbitals) to hold these valence electrons, so upon mixing, 8 molecular orbitals are formed. In order of increasing energy, they are a sigma, sigma*, sigma, pi (two equivalent energy orbitals), pi* (two equivalent energy orbitals) and sigma*. You can see that the 11th and 12th electrons are placed in the two equivalent pi* orbitals. By Hund's rule, they prefer to be unpaired, so the 11th electron is placed in a different orbital as the 12th electron. Since they are both unpaired, the molecule is paragmetic.

Answer 2

Yes, O2 is paramagnetic.
In the states solido and gaseous it is sufficiently paramagnetic. Ok?

Answer 3

Yes.