Hybridization of PCl₃

Phosphorus trichloride (PCl₃) is a chemical compound consisting of one phosphorus (P) atom bonded to three chlorine (Cl) atoms. It is a key representative of phosphorus compounds and finds applications in various chemical processes.

The molecule's structure and bonding can be elucidated by understanding the concept of hybridization in the phosphorus atom. Let’s learn what is the hybridization of PCl₃ in detail.

1.0Hybridization scheme in PCl₃ 

To understand the hybridization scheme for PCl₃ (phosphorus trichloride), we need to look at its molecular geometry and the number of sigma bonds and lone pairs around the phosphorus atom. See number of electrons in ground state and excited state in phosphorus in given diagram. 

In PCl₃ :

• Phosphorus contributes 5 valence electrons.
• Each chlorine atom contributes 1 valence electron.

Now, let's count the number of sigma bonds and lone pairs around phosphorus:

• There are three sigma bonds between phosphorus and the three chlorine atoms.
• There is one lone pair of electrons on phosphorus.

As per the valence shell electron pair repulsion theory, the geometry around phosphorus is tetrahedral (three sigma bonds and one lone pair). The hybridization is determined by the number of sigma bonds and lone pairs.

For PCl₃ :

If there are 3 sigma bonds and 1 lone pair, the hybridization is sp³.

Therefore, the phosphorus in PCl₃ undergoes sp³ hybridization. In sp³ hybridization, one s orbital and three p orbitals combine to form four equivalent sp³ hybrid orbitals. These orbitals are then used to overlap with the orbitals of the chlorine atoms, resulting in the formation of three sigma bonds and one lone pair, giving PCl₃ a trigonal pyramidal molecular geometry.

2.0Physical properties of PCl₃

3.0Bonding in PCl₃ 

• Phosphorus trichloride (PCl₃) exhibits covalent bonding. In PCl₃, phosphorus forms covalent bonds with three chlorine atoms. Covalent bonding involves the sharing of electrons between atoms to achieve a more stable electron configuration.

• Phosphorus in its ground state has the electron configuration: 1s² 2s² 2p⁶ 3s² 3p³.
• Phosphorus has five valence electrons, and in the formation of phosphorus trichloride (PCl₃), it undergoes hybridization to achieve a more suitable arrangement for bonding.                    
• Covalency (PCl₃)- 3
• The Lewis structure of PCl₃ can be determined by arranging the atoms so that they each have a full valence shell. Phosphorus contributes 5 valence electrons, and each chlorine contributes 7 valence electrons, resulting in a total of 26 valence electrons for PCl₃. The Lewis structure can be drawn as: