Magnetic moment Spin-only contribution

Table 16.4 Magnetic Moments Expected for Spin-Only Contributions. ...

Fig. 13 Effective magnetic moment for octahedral dl complexes like Ti(III) solid - k = 1 long dashed -k = 0.7 short dashed - k = 0.4 dot-dashed - k = 0 (a Curie paramagnet with spin-only contribution). Right the calculated energy levels (not to scale, values in cm 1)...

Explain why in high-spin octahedral complexes, orbital contributions to the magnetic moment are only important for d, d, d and d configurations. 

Equation (S6.1) is applicable to the salts of lanthanide ions. These have a partly filled 4f shell, and the 4f orbitals are well shielded from any interaction with the surrounding atoms by filled 5.9, 5p, and 6.9 orbitals, so that, with the notable exceptions, Eu3+ and Sm3+, they behave like isolated ions. For the transition metals, especially those of the 3d series, interaction with the surroundings is considerable. Because of this, the 3d transition-metal ions often have magnetic dipole moments corresponding only to the electron spin contribution. The orbital moment is said to be quenched. In such materials Eq. (S6.1) can then be replaced by a spin-only formula ... 

---