Orbital Hybridization
Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals used
for the description of atomic bonding properties.
sp Hybrid Orbitals
eg: BeF2
The fluorine atom electron configuration:

1s22s22p5


There is an unpaired electron in a 2p orbital
This unpaired 2p electron can be paired with an unpaired electron in the Be atom
to form a covalent bond
The Be atom electron configuration:

1s22s2

In the ground state, there are no unpaired electrons (the Be atom is incapable of
forming a covalent bond with a fluorine atom
However, the Be atom could obtain an unpaired electron by promoting an electron
from the 2s orbital to the 2p orbital:


The orbital diagram for this hybridization would be represented as:
sp2 Hybrid Orbitals
eg: BF3
Boron electron configuration:
Sp3 Hybrid Orbital

eg. CH4
An s orbital can also mix with all 3 p orbitals in the same subshell
CH4
Sp3d Hybrid Orbitals
eg:PF5
Atoms in the third period and higher can utilize d orbitals to form hybrid orbitals
PF5
Find the type of hybridization in following molecules
1. CH3Cl
2. BF3
3. CH4
4. PF5
Molecular shapes of compounds
After having considered the hybridized orbitals and the VSEPR model, we can not take a
systematic approach to rationalize the shapes of many molecules based on the number of
valence electrons.
A summary in the form of a table is given here to account for the concepts of hybrid
orbitals, valence bond theory, VSEPR, resonance structures, and octet rule. In this
table, the geometric shapes of the molecules are described by linear, trigonal planar,
tetrahedral, trigonal bypyramidal, and octahedral. The hybrid orbitals use are sp, sp2,
sp3, sp3d, and sp3d2
The VSEPR number is the same for all molecules of each group. Instead of using NH3E,
and OH2E2, we use :NH3, ::OH2 to emphasize the unshared (or lone) electron pairs.
summary of hybrid orbitals, valence bond theory, VSEPR,
resonance structures, and octet rule.
Trigonal
Trigonal
Linear
Tetrahedral
Octahedral
planar
bipyramidal
sp
sp2
sp3
sp3 d
sp3 d2
BeH2
BH3
CH4
PF5
SF6
BeF2
BF3
CF4
PCl5
IOF5
CO2
CH2O
CCl4
PFCl4
PF6HCN
(>C=O)
CH3Cl
:SF4
SiF62NH4+
:TeF4
:BrF5
HCCH >C=C<
2CO3
:NH3
::ClF3
:IF5
benzene
:PF3
::BrF3
::XeF4
graphite
:SOF2
:::XeF2
fullerenes
::OH2
:::I3•NO2
::SF2
(:::I I2-)
N3:::ICl24:OO2 (O3)
SiO4
:SO2
PO43SO3
SO42ClO4• a lone odd electron
: a lone electron pair