The molecule in which an atom is associated with more than 8 electrons is known as hypervalent molec — Chemical Bonding Chemistry Question

Question

The molecule in which an atom is associated with more than 8 electrons is known as hypervalent molecule and less than 8 electrons is known as hypovalent molecule. All hypervalent molecules must have p$\pi$-d$\pi$ bonding but the molecules having back bonding need not to have always p$\pi$-d$\pi$ bonding.