Ligand field stabilization energies, is it correct to say

[Chemist20]

the following?:

low-spin d5 metal. Energy = -2Δ -4K (where K is exchange energy. i,e. minimization of energy due to parallel spins)

low-spin d6 metal. Energy = -1.6Δ -3K

Therefore: energy needed to add an electron = ΔE= 0.4Δ + K

Is that correct?

maybe I should be talking about Spin Pairing Energy (P) ...

HEEEEEEEEEEEEEEEEEEEEEEEEEEEELP!

 

[DrDu]

The energy to add an extra electron (i.e. electron affinity) depends much more on other factors than ligand field stabilization. This should already be clear from the fact that electron affinity is not zero for atoms in the gas phase where there is no ligand field stabilization.
It mainly depends on the increased intraatomic repulsion of the electrons.

 

[Chemist20]

The energy to add an extra electron (i.e. electron affinity) depends much more on other factors than ligand field stabilization. This should already be clear from the fact that electron affinity is not zero for atoms in the gas phase where there is no ligand field stabilization.
It mainly depends on the increased intraatomic repulsion of the electrons.

that would be the pairing energy right?

 

[DrDu]

that would be the pairing energy right?

The pairing energy would also contribute, but this contribution would be rather small.
Your question is not very specific. What is the concrete situation you have in mind? It would also be helpful to specify the coordination of the complex ...

I would consider some Born cycle, i.e. desolvation of the complex ion, decomplexation of the ion with charge i+1, electron affinity of the ion, formation of the complex with charge i, solvation of the complex. Similar cycle for the ion or atom delivering the electron.
The ligand field statilization only contribute to the second and before last step.
The ligand field stabilization is only a relative stabilization of some set of d orbitals relative to others. Even in a complex where there is no ligand field effect, like going from s^0 to s^1, the energy of complex formation is generally non-zero, e.g. due to the increasing (or decreasing) electrostatic attraction between the central atom and the ligands.

 

[LudusRex]

I cannot confirm or deny the accuracy of the equations provided without knowing the specific context and assumptions being made. However, I can provide some general information about ligand field stabilization energies and spin pairing energies.

Ligand field stabilization energy (LFSE) refers to the energy difference between the high- and low-spin states of a transition metal ion in a complex. This energy is influenced by the interactions between the ligands and the metal ion, as well as the electron-electron repulsions within the metal ion. The LFSE can be calculated using the equation: LFSE = -0.4Δ + 0.6P, where Δ is the crystal field splitting energy and P is the pairing energy.

In the equations provided, it is unclear what the variables Δ and K represent. Typically, Δ represents the crystal field splitting energy, which is the energy difference between the d-orbitals in a complex. The value of Δ is dependent on the geometry of the complex and the nature of the ligands. K, on the other hand, is the spin pairing energy, which refers to the energy required to pair up two electrons with opposite spins in the same orbital. This energy is typically negative, as it reflects the stability gained from spin pairing.

The equation provided for the energy needed to add an electron (ΔE) appears to be a simplified version of the LFSE equation. However, it is important to note that LFSE is a measure of the overall stability of a complex, while ΔE only considers the energy required to add one electron. Additionally, the values of Δ and K may vary depending on the specific complex being studied.

In summary, while the equations provided may be based on some principles of LFSE and spin pairing energy, it is important to carefully consider the context and assumptions being made in order to determine their accuracy. It may also be helpful to consult with other scientists in the field for further clarification and discussion.