Question

The number of species from the following that are involved in $sp^3d^2$ hybridization is $[Co(NH_3)_6]^{3+}$, $SF_6$, $[CrF_6]^{3-}$, $[CoF_6]^{3-}$, $[Mn(CN)_6]^{3-}$ and $[MnCl_6]^{3-}$.

Answer 1

3

Answer 2

For an octahedral complex, the inner orbital (d²sp³) hybridization is used when the metal ion has low spin configuration (often with strong‐field ligands) because two 3d orbitals remain vacant, while the outer orbital (sp³d²) hybridization is used in high spin complexes (with weak‐field ligands) when all the 3d orbitals are occupied or insufficient vacancies exist.

1. $[Co(NH_3)_6]^{3+}$: $Co(III)$ with $NH_3$ (a moderately strong field ligand) is low spin $\rightarrow$ uses $d^2sp^3$.
2. $SF_6$: Sulfur uses 3s, 3p, and 3d orbitals $\rightarrow$ $sp^3d^2$ hybridization.
3. $[CrF_6]^{3-}$: $Cr(III)$ ($d^3$) has three electrons occupying $t_{2g}$, leaving two inner d‐orbitals free $\rightarrow$ $d^2sp^3$ hybridization.
4. $[CoF_6]^{3-}$: $Co(III)$ with $F^⁻$ (a weak field ligand) is forced high spin ($d^6$ high spin) and does not have two vacant 3d orbitals $\rightarrow$ uses $sp^3d^2$ hybridization.
5. $[Mn(CN)_6]^{3-}$: $Mn(III)$ with $CN^⁻$ (a strong field ligand) is low spin ($d^4$ low spin) $\rightarrow$ uses $d^2sp^3$ hybridization.
6. $[MnCl_6]^{3-}$: $Mn(III)$ with $Cl^⁻$ (a weak field ligand) is high spin ($d^4$ high spin) $\rightarrow$ uses $sp^3d^2$ hybridization.

Thus, the species with $sp^3d^2$ hybridization are:

• $SF_6$
• $[CoF_6]^{3-}$
• $[MnCl_6]^{3-}$