Hybridisation of BeCl₂

Beryllium chloride (BeCl₂) is a compound made from two elements: beryllium and chlorine. It shows interesting behaviour in different states. In the solid state, BeCl₂ exists in a polymeric structure, while in the gaseous state, it forms a dimer with a linear shape. The compound is a carcinogen. It is often used as a catalyst, laboratory reagent, and in the extraction of Beryllium.

Let’s understand the hybridisation of BeCl₂

What is the Hybridisation of Beryllium Chloride?

When it comes to hybridisation, BeCl₂ is a great example to understand how atomic orbitals mix to form new ones. For beryllium chloride, the hybridisation varies in linear and polymeric forms.

In the gaseous form, the beryllium atom undergoes sp hybridisation, using one 2s and one 2p orbital to form two equivalent sp hybrid orbitals. These hybrid orbitals then form two sigma (σ) bonds with chlorine atoms. It results in a linear structure with a bond angle of 180°.

In solid form, it has a polymeric structure due to bridging chlorine atoms.

Hybridisation in Linear Form

formula

Electronic Configuration of Beryllium

The electronic configuration of Beryllium in the ground state is:

formula

The Excitation of Beryllium

The electron excitation leads to the movement of an electron into the p orbital. This leads to s being half-filled. Thus, the new electronic configuration is:

formula

Now, the s and p orbitals combine with the p orbital of two chlorine atoms to form the compound.

Formation of Hybrid Orbitals

Since one 2s and one 2p orbital participate in the reaction, the Beryllium chloride has sp hybridisation.

Hybridisation of beryllium chloride

Hybridisation in Polymeric Form

In the polymeric form of Beryllium Chloride, each beryllium atom forms two regular covalent bonds with chlorine atoms. They also form two additional coordinate bonds. These coordinate bonds occur when lone pairs from chlorine atoms are donated to the electron-deficient beryllium atoms to help them complete their octet. As a result of forming four bonds, the hybridisation of beryllium in the polymeric structure becomes sp³.

Property	Description
Chemical Formula	BeCl₂
Hybridisation (Gas)	sp
Shape (Gas)	Linear
Bond Angle (Gas)	180°
Hybridisation (Solid)	sp³
Structure (Solid)	Polymeric (due to bridging Cl atoms)
Bond Type	σ (sigma) bonds + coordinate bonds in solid state
Formal Charge (Be)	0 (using formal charge formula)
Polarity	Non-polar (symmetrical structure cancels dipoles)

Formal Charge in Beryllium Chloride

To calculate the formal charge in BeCl₂, use the formula:

formula

Thus, the Lewis structure of the compound is valid.

Summing Up

BeCl₂ is an interesting compound with different structures in gaseous and solid states. In the gaseous form, beryllium undergoes sp hybridisation and forms two sigma bonds and a linear structure with a bond angle of 180°.

In the solid state, due to bridging chlorine atoms, BeCl₂ forms a polymeric chain. Here, beryllium completes its octet via coordinate bonds and has sp³ hybridisation. BeCl₂ is electrophilic in nature and finds various industrial and laboratory applications, but its toxicity demands caution in handling.

Frequently Asked Questions

Q1. What is the physical state of Beryllium Chloride?

Beryllium chloride exists as a white crystalline solid. However, its highly hygroscopic nature leads to the formation of hydrated crystals. Thus, one will find Beryllium Chloride Dihydrate .

formula