PCl5
TeF4
BrF3
Orbitals used by pairs of electrons in VB theory need to be created from atomic orbitals: overlap between orbitals can give the required increase in electron density between nuclei. A problem arises, however, because atomic orbitals do not always give the right geometries.
Hybridization: overlap of two or more atomic orbitals on the same atomic center.
This requires orbitals to be about the same energy (or same size).
geometry
hybrid
linear
sp, sd
trigonal
sp2, sd2
tetrahedral
sp3, sd3
square planar
dsp2
trigonal bipyramid
dsp3
octahedral
d2sp3
