Abstract In this paper by taking into account the ligand displacements due to the repulsive forces of charge compensator Li+] vacancies and hence the increase of bonding angle β for 3dn ions (Cr3+] December Ni2+], Mn2+], Fe3+] and Co2+]) in α-LiIO3 crystals, the signs of EPR parameters (D and △g = g ∥ - g ⊥) for these crystals have been explained reasonably in a consisten manner from the signs of spin-lattice coupling coefficients.