I have been learning about SP3 hybridisation and slightly confused why it it results in 4 sp3 orbitals.

My understanding is this...

The S orbital is spherical and uniform whilst the p orbitals are made of 2 lobes.

There are 3 p orbitals Px Py and Pz.

So if each of these p orbitals combines respectively with the s orbital you end up with 3 new ones. Where does the remaining orbital come from?

Thanks very much,


  • 2
    $\begingroup$ It would be quite wrong to say that each sp3 orbital comes from specific p orbital. Instead, they are all mixed together. $\endgroup$ – Ivan Neretin Dec 2 '19 at 15:26
  • 1
    $\begingroup$ The number of atomic orbitals equals the number of (hybrid) molecular orbitals. $\endgroup$ – user55119 Dec 2 '19 at 16:40

Actually one s orbital and three p "mix" together, hybridize to form four sp3 orbitals.

Maybe this could help:

enter image description here


The 2s and 2p orbitals are close to one another in energy. In the case of a single hydrogen atom, these states are in fact the same in energy, although you would not see a hydrogen atom with an electron in the 2p orbital unless it had been excited by light or a collison.

Because these orbitals are close in energy, the hybridization concept promotes the idea that these orbitals readily mix. It's a good thing that they do, because this causes the tetrahedral shape of fully saturated carbon.

  • $\begingroup$ Uhhh... here we go with the toxic downvoting of reasonable responses. $\endgroup$ – Bertram Dec 6 '19 at 19:15

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