Question

Why is nitric oxide paramagnetic in gaseous state but the solid obtained on cooling it,is diamagnetic?

Answer 1

Structure and number of electrons in nitric oxide

* Nitric oxide $\left(NO\right)$ has odd number of electrons in its molecule.

* 7 electrons of N and 8 electrons of O atom that equal to tatal of 15 electrons.

* Its structure is


* Due to the presence of unpaired electrons on either N or O atoms, it is paramagnetic in the gaseous state.

* However, in the liquid and solid state, the unpaired electron is involved in the formation of domer $\left(N_2{O}_2\right)$ which is diamagnetic in nature.