(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Determine the LFSE for the following octahedral ions from first principles.

d) Low Spin d^{6}

e) d^{9}

2. Relevant equations

LFSE=(x0.4-y0.6)[itex]\Delta[/itex]_{o}

3. The attempt at a solution

d) t_{2g}^{6}e_{g}^{0}

LFSE=((6)0.4-(0)0.6)[itex]\Delta[/itex]_{o}=2.4[itex]\Delta[/itex]_{o}

e) t_{2g}^{6}e_{g}^{3}

LFSE=((6)0.4-(3)0.6)[itex]\Delta[/itex]_{o}=0.6[itex]\Delta[/itex]_{o}-P

Actual solutions:

d) 2.4[itex]\Delta[/itex]_{o}-2P

"However, since one pair of electrons would be paired in a spherical field the additional pairing energy is 2P."

e) 0.6[itex]\Delta[/itex]_{o}

"However, since all four pairs of electrons would be paired in a spherical field there is no additional pairing energy."

I'm really confused about the treatment of pairing energy. I'd really appreciate if someone could explain when I should/should not include pairing energy. Initially I thought any electrons that moved up and paired in e_{g}would cause the addition of pairing energy but it seems it isn't so. I don't really understand what it means by "spherical field".

"

Thank you!

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# Pairing Energy/LFSE (Inorganic)

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