A trihalide of Boron, BCl3 consists of a single boron atom and three atom of Chlorine. That is a colorless inorganic compound that has a pungent odor and also appears together fumes in air. It finds usage in miscellaneous applications, consisting of the manufacturing of element Boron.

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BCl3 is an wild reagent and also reacts conveniently with humidity to provide Hydrochloric Acid or HCl. Boron Trichloride is produced through industrial method by straight chlorination that Boron Oxide and Carbon in ~ high temperatures. The compound has the following properties:

Name the the moleculeBoron Trichloride (BCl3)
No. The valence electrons3+ (7×3) = 24 valence electrons
Bond Angles120°
Molecular Geometry of BCl3Trigonal Planar

This write-up will incorporate other properties of BCl3 such as its Lewis Structure, molecule geometry, shortcut angles and also its shape.


BCl3 Valence Electrons

The calculation of valence electrons of BCl3 is an important step prior to we obtain to the Lewis structure. The total variety of valence electron in BCl3 is calculated together follows:

Total number of valence electron in BCl3 = Valence electron in Boron + Valence electrons in Chlorine 1

Boron has an atomic number of 5, thus having three valence electrons. Together we recognize already, Chlorine has seven valence electrons. Because there space three atom of Chlorine, we multiply the variety of valence electrons current by 3. This gives us 21 valence electrons because that 3 Chlorine atoms. Therefore, from the over relation 1, the total variety of valence electron in BCl3 is offered by

Total Valence electron in BCl3 = 3 (from Boron) + 7 x 3 (from Chlorine)

= 24 Valence Electrons for this reason BCl3 has actually 24 complete valence electrons.

BCl3 Lewis structure

The Lewis dot frameworks of a compound stand for a schematic arrangement of its ingredient molecules, atoms, and electron bonds.

Lewis structures are attracted in accordance through the octet rule, whereby each atom in the molecule make the efforts to achieve 8 electrons in that outermost shell. There are a few exceptions to this rule, with Boron being one of them.

Here for BCl3, the Boron atom is put at the centre of the molecule together it is the least electronegative. It climate facilitates the bonding that pairs in between itself and the surrounding Chlorine atoms.

The 24 valence electrons are placed accordingly, and bonds are formed. The lone pairs room placed starting from the external end, walking inwards.

Boron forms covalent bonds with the surrounding Chlorine atom by share its 3 valence electrons. This satisfies the octet dominance of Chlorine yet Boron is left with just 6 electron in the outermost shell. Boron doesn’t necessarily have to fulfil the octet rule and also is an exemption to it.

However, we can type a dual bond in between one of the Chlorine atoms and Boron to satisfy the octet ascendancy fully. Hence, over there are currently two different Lewis structures for BCl3.


Using the concept of officially charges, we have the right to determine i beg your pardon Lewis is the many stable state because that the molecule. The structure with the most formal charges close to zero is taken into consideration to be the many stable.

FC = Valence electron – Non-bonding electron – (Bonding electrons ÷ 2) formal charges for structure 1 are offered by:


Formal fees for structure 2 through the double bond in place is offered by:

Cl –double bonding744/2+1
Cl- solitary bond762/20

As you can see native the above tables, Boron’s Lewis framework doesn’t call for it to fulfill the octet preeminence in its most stable form.

BCl3 Hybridization

Boron’s digital configuration is provided by 1s2 2s2 2p1. Boron develops three covalent bonds v Chlorine. In its excited state, one of the electrons moves up from the 2s orbital to the 2p orbital. Hybridization now occurs, and also one 2s and also two 2p orbitals of Boron kind bonds through the 3p orbital of Chlorine, thus developing three sp-p bonds.

Therefore, the hybridization of BCl3 is sp2.


BCl3 Bond Angles

The molecular structure of BCl3 functions Boron together the central atom and also three Chlorine atoms surrounding it. As result of the visibility of lone pairs, the Chlorine atom repel every other forming bond angle of 120°.

BCl3 molecule Geometry and Shape

Boron develops the main atom in the molecule, v the Chlorine atom pushing as far away indigenous each various other as possible. We have actually the 3 Chlorine atom arranged in one equidistant manner roughly the Boron atom.

Since the steric number of this molecule is 3, it forms a Trigonal Planar structure with bond angle of about 120°. This also occurs because Boron is an exception to the octet rule.


Let’s quickly summarize the salient features of BCl3.

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BCl3 is composed of one Boron atom and also three Chlorine atomsIn its most stable state, Boron develops three covalent bonds v the surrounding Chlorine atom making for 3 bonded pairs in the centre.BCl3 has an sp2 hybridization state.BCl3 has a trigonal planar structure with bond angle of 120°.