What is the hybridisation of [Co(H₂O)₆]³⁺? [duplicate]








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[Why is it wrong to use the concept of hybridization for transition metal complexes?](/questions/76726/why-is-it-wrong-to-use-the-concept-of-hybridization-for-transition-metal-complex)

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There's a lot of ambiguity in the hybridisation of $\ce{Co^3+}$ in its hexaaqua complex; is it a high spin or low spin complex? As theoretically the CFSE is less than P so it should be low spin, but in a lot of places, it's assumed to be high spin.




Holleman/Wiberg states (translation by me)



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> $\ce{Co^{3+}}$ usually forms octahedral low-spin complexes, because it is the only way to achieve a high ligand-field stabilization energy. Octahedral high-spin complexes are typically an exception; they are formed with the "weakest" ligands (fluoride): $\ce{[CoF6]^{3-}}$, $\ce{[CoF3(H2O)3]}$ (the ion $\ce{[Co(H2O)6]^{3+}}$ is in the low-spin state).
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and further



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> That octahedral $\ce{Co^{3+}}$ complexes from a magnetic standpoint are in the low-spin state most of the time, while complexes of the isoelectronic $\ce{Fe^{2+}}$ prefer the high-spin state most of the time, is due to the higher amount of ligand field splitting, following the increased charge on $\ce{Co^{3+}}$.
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Source: Holleman, Wiberg: Lehrbuch der Anorganischen Chemie, 101. edition, de Gruyter, 1995.


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