Octahedral transition metal complexes, spin

Such a balance between the one- and two-electron terms in the energy play important roles in several places in chemistry. For example the relative stability of high spin (large P/A ) and low spin (small P/A ) octahedral transition metal complexes is set by a similar ratio. Here P is the pairing energy associated with a pair of electrons (a combination of exchange and coulomb terms) and A the ej splitting. In fact there are observations from molecular coordination chemistry which are of use to... 

Ruthenium(III) complexes are seen in Tables 8.2 and 8.3 to be kinetically comparable to the corresponding chromium(III) species, despite a larger Dq for Rura, because the LFAE factor is lower for low-spin d5 than for d3. For Ru(H20)63+, AVjx indicates a much more associative mode of activation than for Ru(H20)62+, which seems typical of octahedral transition metal complexes... 

Discuss your observed magnetic moment values in terms of the number of unpaired electrons predicted for each transition-metal complex assuming octahedral structures. Comment on any differences from the predicted spin-only moments. 

We outline the application to an octahedral id transition metal complex, as the relations derived in this case are used to interpret the results of spin density measurements (see Sections VI. A and VI. B). A similar approach may be used for other coordinations and for other metals. Some general consequences relating the symmetry properties of complexes and a molecular orbital model of bonding have been combined in the angular overlap model< >... 

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