HYBRIDISATION

Rules for hybridisation

• Only orbitals of smaller energies belonging to the same atom or ion can hybridize together

• Number orbitals are similar umber of hybrid orbitals produced is equal to the number of orbitals undergoing hybridization. Hybrid bonds are stronger than the single non hybridized bonds of comparable energy

• Most of the hybrid orbitals are similar but they are not necessarily identical in shape. They differ from one another in their orientation in space.

• For equivalent hybrid the orientation in space is determined by number of orbitals mixed and which of x, y and z axis is preferred

• From the type of hybridization one can predict the geometry and bond angle of a molecule

• An orbital which has been used to build up a hybrid orbital is no longer available to hold electron in its pure form

Types of hybridisation

• sp – hybridisation (mixing of s and pz orbitals)

• Linear (or diagonal hybrid orbitals

Example: BeCl2

sp2 hybridisation• sp2 – hybridisation (mixing of s px and pz orbitals)

• Trigonal planar (or triangular) hybrid orbitals

Example: BeCl3Trigonal planar shape

SnCl2 (Angular or bent (V-shape)

NO3Planar triangular shape

sp3 hybridisation

• sp3 – hybridisation (mixing of s + px + pz + pz orbitals)

• Tetrahedral hybrid orbitals

pz

Example: CH4

• Tetrahedral

Trigonal pyramidal V-shaped Linear

:NH3 H2O HF

sp3d hybridisation

• sp3d – hybridization

• (mixing of s + px + pz + pz + dz2orbitals)

• Trigonal bipymramidal

• Five hybrid orbitals are non equivalent

• three equatorial hybrids (or basal or planar hybrids)

• Two axial or polar hybrids

Example

PF5, :SF4, ClF3

Trigonal bipyramidal Distorted bipyramidal T-shaped

sp3d2 hybridisation

• sp3d2 – hybridisation (mixing of s + px + pz + pz + dz2 + dx2-y2 orbitals)

• octahedral

Example:

SF6, :IF5 XeF4

Octahedral Square pyramidal Square planar

sp3d3 hybridisation

• sp3d3 – hybridisation (mixing of s + px + pz + pz + dxy + dyz + dyz orbitals)

• Pentagonal bipyramidal

• Example: IF7, XeF6

dsp2 hybridisation

• dsp2 – hybridisation (mixing of s + px + py + dx2-y2orbitals)

• Square planar hybrid orbitals

dsp3 hybridisation

• dsp3 – hybridisation (mixing of s + px + py + pz + dx2-y2orbitals)

• Square pyramidal hybrid orbitals