9.4. Hybridization of Atomic Orbitals http://www.ck12.org
The occupied orbitals are then hybridized, and the result is a pair ofsphybrid orbitals. The two remainingporbitals
(arbitrarily chosen to bepyandpz) do not hybridize and remain unoccupied.
The geometry of thesphybrid orbitals is linear, with the large lobes of the two orbitals pointing in opposite directions
along one axis, arbitrarily defined as the x-axis (Figure9.41). Each can bond with a 1sorbital from a hydrogen
atom to form the linear BeH 2 molecule.
FIGURE 9.41
The process ofsphybridization involves
the mixing of ansorbital with a singlep
orbital (conventionally thepxorbital), to
form a set of twosphybrids. The two
lobes of thesphybrids point in opposite
directions to produce a linear molecule.Other molecules whose electron domain geometry is linear and for whom hybridization is necessary also formsp
hybrid orbitals. Examples include CO 2 and C 2 H 2 , which will be discussed further in the section on hybridization
and multiple bonds.
Hybridization of
Elements in the third period and beyond are capable of expanding their octet to form molecules with either trigonal
bipyramidal or octahedral electron domain geometries. In order to accomplish this, the previously unoccupied
orbitals in thedsublevel of the central atom are involved in the hybridization process.
For phosphorus pentachloride (PCl 5 ), the electron domain and molecular geometries are trigonal bipyramidal. The
electron promotion is from the 3sorbital to an empty 3dorbital.