Answer to Question #84579 in Inorganic Chemistry for Sk Abidur Rahaman

Question

Differentiate between equivalent & non-equivalent hybrid orbitals with specific example of each.

Answer 1

1. Equivalent hybridisation

Equivalent hybridization is a type of hybridization in which all hybrid orbitals are of same shape, size and energy. All bond angles are the same. For example sp³ hybridisation (molecule of CH₄): one s and three p orbitals mix to form 4 sp³ hybrid orbitals having the same shape (tetraherdal), size, energy, and bond angle (10928^'):

Tetrahedral sp³ bounding in methane

2. Non-eqiuvalent orbitals

In Non Equivalent Hybridization all hybrid orbitals do not have the same shape, size and energy. Bond angles are also different. For example molecule of PCl_5. Hybridization is sp³d

Two types of orbiatal geometry are posiible in this case:

i) trigonal bipyramidal

In this case two types of hybrid orbitals are formed: three equivalent orbitals developed from s+p_x + p_y, which lie in the equivalent plane, bond algle between orbitals is 120 and two equivalent orbitals developed form p_z and d_z² , which lie in the axial plane, bond angle between orbitals is 180⁰ .

ii) square pyramidal

In this case two types of hybrid orbitals are formed: four equivalent orbitals developed from s+p_x + p_y + d_x2-y2 and one pure p_z orbital, which lie perpendicular to the xy-plane