# Is #NO^-# Paramagnetic or Diamagnetic?

##### 1 Answer

Apr 7, 2016

The MO diagram for

(The original was this; I added the orbital depictions and symmetry labels.)

Quick overview of what the labels correspond to what MOs:

#1a_1# is the#sigma_(2s)# bonding MO.#2a_1# is the#sigma_(2s)^"*"# antibonding MO.#1b_1# is the#pi_(2p_x)# bonding MO.#1b_2# is the#pi_(2p_y)# bonding MO.#3a_1# is the#sigma_(2p_z)# bonding MO, but it's relatively nonbonding with respect to oxygen.#2b_1# is the#pi_(2p_x)^"*"# antibonding MO.#2b_2# is the#pi_(2p_y)^"*"# antibonding MO.#4a_1# is the#sigma_(2p_z)^"*"# antibonding MO.

Since this is **antibonding MO**.

That **increases** its paramagnetic properties, as there exist *two unpaired electrons* now instead of just one.

*CHALLENGE: What does that do to the #N-O# #pi# bond? Does it weaken or strengthen it? (Hint: Consider the *

**bond order**). What about #NO^(+)#? Is that diamagnetic, and how do you know?