sp³ Hybridisation
The mixing of one s and three p orbitals to give four hybrid orbitals directed towards the corners of a tetrahedron.
Formula / equation
4 hybrids, 109.5°
Unit
degrees
In depth
With no p orbital left over, sp³ atoms form only sigma bonds and permit free rotation, which is why alkanes are conformationally flexible. Lone pairs also occupy sp³ hybrids, so the arrangement covers not only methane but the pyramidal ammonia and bent water molecules.
Examples in the real world
Methane and ethane, diamond's entire lattice, and the oxygen of water bearing two lone pairs.