Energy spin-pairing

Note phen is 1, 10 orthophenanthroline. Note the change to low-spin, paired d electron, states gains tr-acceptor and /r-donoi strength offsetting spin-pairing energy. 

For a given series the value of D, the spin-pairing energy, does not in fact stay constant, but its average value for a given dq configuration is 7/6 (5/2 B + C), and for MF ions D ranges only between 3.9 and 4.7 kK. 

An energy term using the same form as equation 7 to account for the spin-pairing energy for low-spin electronic configurations (33) ... 

Subsequently, LFMM was extended with an explicit spin-pairing energy (18). This is an empirical term with the same functional form as the AOM parameters (Eq. 7) and is significantly easier to implement than to express the ligand field stabilization energy as a function of the many-electron Russell-Saunders terms (60). Preliminary indications (61) for Fe(II) species suggest the approach is satisfactory and we expect to be able to use LFMM to study phenomena like spin crossover. 

Curve a - spin-pairing energy of / set i.e. Smax barycentre relative to b. 

Metal Ion B Spin pairing energy change 10 Dq AXopt... 

Table 10b Spin-pairing Energies (11) and Spin-crossover Ligand Field Strengths (Dq/B) for

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