How do I know which transition metal complex is most stable?

1 Answer
Jul 29, 2017

#"How do you compare apples and oranges.......?"#

Explanation:

I take it, and I fully accept that I may be wrong, that your question relates to ligand field theory, and the electronic configuration of a transition metal ion in an octahedral coordination complex......

You know that that when a transition metal ion is in octahedral coordination, the ligand field strongly differentiates between axial and non-axial #"d-orbitals"#. For octahedral coordination, this occurs for #d^4, d^5,# #d^6#, and #d^7# metal ions, which can generate low spin (differentiation between #t_"2g"# and #e_g# is large), and high spin (differentiation between #t_"2g"# and #e_g# is small) complexes.

Half-filled d-orbitals, #d^5#, and fully-filled d-orbital configurations, #d^10#, tend to have a special stability, but for each scenario it is hard to find a metric with which to make meaningful comparison.