Is magnesium oxide magnetic?

Hint: The magnesium oxide has no electrons in the d orbital in any of its constituent ions, but can be considered as the prototype of ferromagnetism i.e., the magnetism can be induced in such compounds which consist of completely filled d orbital or no d orbital electrons.

Complete Step by Step Solution:
Magnesium oxide $(MgO)$ is an inorganic compound which exhibits a rock salt structure consisting of face centred cubic lattice. The purest form of magnesium oxide is non-magnetic while the magnetism can be induced by creating defects or vacancies inside the structure of the compound.

Contribution of these defects to this kind of magnetism which is associated with the spin triplet state of vacancy of magnesium. The magnetic interactions in magnesium oxide occur through the bond spin polarisation in vacancies in the structure of the compound. The defects within the compound can be increased by doping of the structure with magnetic or non-magnetic ions. Experimentally, it was observed that the magnetism in magnesium oxide also occurred due to the electrons in the 2p orbitals of electrons surrounding the magnesium vacancies.

Therefore, we can say that the magnesium oxide is non-magnetic in its purest state while it can show ${d^o}$ ferromagnetism inducing defects in its solid state structure.

Note: It is important to note that the metals consisting of completely filled d orbitals are known as pseudo transition metals or d orbitals with zero electrons show the similar type of magnetic properties as observed in case of magnesium oxide i.e., ferromagnetism prototype.