Explain the hybridization involved in PCl₅ molecule ?

The hybridization involved in the PCl₅ hybridization process is sp³d hybridization. Here’s how it works:

1. Electronic Configuration of Phosphorus

In the ground state, the electronic configuration of phosphorus is:

1s² 2s² 2p⁶ 3s² 3p³

However, phosphorus needs to form five bonds in PCl₅, so it undergoes excitation. One electron from the 3s orbital moves to the 3d orbital. This gives the excited state electronic configuration:

1s² 2s² 2p⁶ 3s¹ 3p³ 3d¹

2. Formation of Hybrid Orbitals

In the excited state, phosphorus combines one 3s orbital, three 3p orbitals, and one 3d orbital to form five equivalent sp³d hybrid orbitals. These hybrid orbitals are directed in space to minimize repulsion and achieve maximum stability.

3. Bond Formation with Chlorine

Each of these five sp³d hybrid orbitals of phosphorus overlaps with the half-filled 3p orbitals of five chlorine atoms to form five sigma (σ) bonds.

The bonding involves:

• σ(sp³d)-p overlaps between the phosphorus hybrid orbitals and chlorine’s 3p_z orbitals.

4. Molecular Shape

The resulting structure of PCl₅ is trigonal bipyramidal, with:

• Three bonds in the equatorial plane at 120° to each other.
• Two bonds in the axial positions at 90° to the equatorial plane.
• A bond angle of 180° between the two axial bonds.