How does a molecule (for example, ClF₅) have a steric number of more than 4 if SP³ hybridisation is the maximum? [duplicate]








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[How can Iodine bond with 5 Fluorines in Iodine Pentafluoride?](/questions/19433/how-can-iodine-bond-with-5-fluorines-in-iodine-pentafluoride)

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Closed 2 years ago.




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> "The sum of the number of atoms bonded to a central atom and the number of lone pairs formed by its nonbonding valence electrons is known as the central atom's steric number."
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> [Wikipedia's entry about "Steric number"](https://en.wikipedia.org/wiki/Steric_number)
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I just started learning hybridisation and stuff for fun, and I just found out this "oddity".




The steric number of $\ce{ClF\_5}$ is 6, and this is possible because $\ce{sp^3}$ hybridization is not the maximum, or the 'limit' to hybridization. In the case of $\ce{ClF\_5}$ the hybridization is $\ce{sp^3d^2}$, the hybridization involving the $\ce{3s}$, $\ce{3p}$ and $\ce{3d}$ orbitals.


[![MOT](https://i.stack.imgur.com/O7nbg.jpg)](https://i.stack.imgur.com/O7nbg.jpg)


Image credits: <https://techiescientist.com/clf5-lewis-structure/>


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