CHM 401

 

Structure Prediction using VSEPR

PF5

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