The ligand and quadrupole interactions parameters have been measured at 4.2 K by ENDOR for three shells of 35,37Cl, 133Cs and 23Na neighbours around Cr3+ and Yb3+ substitutional impurities. The ligand interaction parameters were analysed by means of expressions for spin densities obtained by the configurational interaction method. The quadrupole interaction parameters have been discussed in terms of a point-dipole model, and local deformation around the magnetic ions being taken into account.