Reference = N.W.Ashcroft, N.D. Mermin, Solid State Physics, Saunders College Publishing, USA, (1976) pages 657 and 658.
L = total orbital angular momentum (quantum number of orbital angular momentum)
S = total electronic spin angular momentum (quantum number of ...)
J = total electronic angular momentum (quantum number of ...)
Ground State Term: 2S+1XJ, X="S" for L=0, X="P" for L=1, X="D" for L=2, X="F" for L=3, Term Symbol - Wiki.
calculated peff = g(J,L,S) sqrt[J(J+1)], g = 3/2 + (1/2)[( S(S+1)-L(L+1) )/J(J+1)] = 2.0 za S=J.
From Curie Constant C: peff = \sqrt(8*C), units: C = X*T in emu K/mol, [peff] = BM (Bohr magneton).
REAR EARTH IONS:
| Element | Basic electron configuration | Ground State Term | calculated peff | measured peff |
| La | 4f0 | 1S | 0.00 | diamagnetic |
| Ce | 4f1 | 2F5/2 | 2.54 | 2.4 |
| Pr | 4f2 | 3H4 | 3.58 | 3.5 |
| Nd | 4f3 | 4I9/2 | 3.62 | 3.5 |
| Pm | 4f4 | 5I4 | 2.68 | - |
| Sm | 4f5 | 6H5/2 | 0.84 | 1.5 (due to low-lying J-multiplets) |
| Eu | 4f6 | 7F0 | 0.00 | 3.4 (due to low-lying J-multiplets) |
| Gd | 4f7 | 8S7/2 | 7.94 | 8.0 |
| Tb | 4f8 | 7F6 | 9.72 | 9.5 |
| Dy | 4f9 | 6H15/2 | 10.63 | 10.6 |
| Ho | 4f10 | 5I8 | 10.60 | 10.4 |
| Er | 4f11 | 4I15/2 | 9.59 | 9.5 |
| Tm | 4f12 | 3H6 | 7.57 | 7.3 |
| Yb | 4f13 | 2F7/2 | 4.54 | 4.5 |
| Lu | 4f14 | 1S | 0.00 | diamagnetic |
The IRON (3d) GROUP IONS:
| Ion | Basic electron configuration | Ground State Term | calculated peff (J=S) | calculated peff (J = |L+-S| | measured peff |
| Ti3+ | 3d1 | 2D3/2 | 1.73 | 1.55 | - |
| V4+ | 3d1 | 2D3/2 | 1.73 | 1.55 | 1.8 |
| V3+ | 3d2 | 3F2 | 2.83 | 1.63 | 2.8 |
| V5+ | does not carry any local magnetic moment on d-electrons | ||||
| V2+ | 3d3 | 4F3/2 | 3.87 | 0.77 | 3.8 |
| Cr3+, V2+ | 3d3 | 4F3/2 | 3.87 | 0.77 | 3.8 (3.7 for Cr) |
| Mn4+ | 3d3 | 4F3/2 | 3.87 | 0.77 | 4.0 |
| Cr2+, V2+ | 3d4 | 5D0 | 4.90 | 0 | 4.8 |
| Mn3+ | 3d4 | 5D0 | 4.90 | 0 | 5.0 |
| Mn2+ | 3d5 | 6S5/2 | 5.92 | 5.92 | 5.9 |
| Fe3+ | 3d5 | 6S5/2 | 5.92 | 5.92 | 5.9 |
| Fe2+ | 3d6 | 5D4 | 4.90 | 6.70 | 5.4 |
| Co2+ | 3d7 | 4F9/2 | 3.87 | 6.54 | 4.8 |
| Ni2+ | 3d8 | 3F4 | 2.83 | 5.59 | 3.2 |
| Cu2+ | 3d9 | 2D5/2 | 1.73 | 3.55 | 1.9 |
| Ce3+ | 4f1 | 2F5/2 | No quenching | 2.54 | 2.4 |
Ni1+ has S=1/2 and d9 as Cu2+. Reference PRL (Ni1+/Ni2+).