Question

Find the number of delta bonding molecular orbital from the following set if z is the internuclear axis:
\[{{d}_{{{x}^{2}}-{{y}^{2}}}}\] and \[{{d}_{xz}}\] , \[{{d}_{{{x}^{2}}-{{y}^{2}}}}\] or \[{{d}_{xz}}\]

Answer 1

Hint: In chemistry, the delta bonds are covalent chemical bonds, where four lobes of one involved atomic orbital overlap four lobes of the other involved atomic orbital and form a molecular orbital. This overlap leads to the formation of a bonding molecular orbital with two nodal planes which contain the internuclear axis which is the Z-axis in this case and go through both atoms. So, the lobes of the combining orbitals must necessarily be in the X-Y plane.

Complete answer:
Here, the number of delta bonding molecular orbital from the following set if z is the internuclear axis is 1.
Delta bonding molecular orbital is formed by the overlap of \[{{d}_{{{x}^{2}}-{{y}^{2}}}}\]and \[{{d}_{{{x}^{2}}-{{y}^{2}}}}\] orbitals when z is the internuclear axis. If we consider overlapping with \[{{d}_{xz}}\], it won’t be feasible because a successful overlap requires two conditions, which are the combining orbitals should be of the same energy and should have the same orientation in space. The \[{{d}_{xz}}\]orbital lies in the X-Y plane intersecting the quarters whereas the orbital has its lobes lying towards X-axis and Y- axis.
So, the correct answer is 1.

Note: Delta bonds are formed by sideways overlap of four lobes of d-orbitals. Delta bonds are weaker than sigma bonds but stronger than pi bonds. For example, there is one delta bond found in the compound \[{{\left[ {{\operatorname{Re}}_{2}}C{{l}_{8}} \right]}^{2-}}\].