The calculation of the contours for is similar to that of except that there are different signs of contours in different regions. The plots of and involved s orbitals on atoms A and B. We can now use the linear combinations using p orbitals. The four combinations that can be made are
(7.5)
(7.6)
(7.7)
(7.8)
In the orbitals to (fig 7.3 (b) and fig 7.3 (a) the MOs have cylindrical symmetry. What this means is that if the orbital is rotated with respect to the internuclear axis, it does not change in shape (or value) at any point. This is analogous to a sphere which does not change in value (i.e., the value of the function defining the sphere) at any point when it is rotated with respect to any axis passing through the center of the sphere. The orbitals to are called (cylindrical symmetry) orbitals. The bonding orbitals are and the antibonding ones . In the orbital and , there is a sideways overlap of orbitals and there is planar symmetry (with respect to the xz plane). These are referred to as and orbitals. Instead of px orbitals we could have used py orbitals to get the sideways overlap.
The plane of symmetry in this case would have been the yz plane. The molecular axis is usually taken to be the z axis.
except that there are different signs of contours in different regions. The plots of 
and 
involved s orbitals on atoms A and B. We can now use the linear combinations using p orbitals. The four combinations that can be made are 
to 
(fig 7.3 (b) and fig 7.3 (a) the MOs have cylindrical symmetry. What this means is that if the orbital is rotated with respect to the internuclear axis, it does not change in shape (or value) at any point. This is analogous to a sphere which does not change in value (i.e., the value of the function defining the sphere) at any point when it is rotated with respect to any axis passing through the center of the sphere. The orbitals 
to 
are called 
(cylindrical symmetry) orbitals. The bonding orbitals are 
and the antibonding ones 
. In the orbital 
and 
, there is a sideways overlap of orbitals and there is planar symmetry (with respect to the xz plane). These are referred to as 
and 
orbitals. Instead of px orbitals we could have used py orbitals to get the sideways overlap. 
