The boron trichloride chemical formula is BCl3. Drawing BCl3 Lewis Structure is very easy to by using the following method. Here in this post, we described step by step method to construct BCl3 Lewis Structure. The boron and chlorine elements come as the member of the boron and halogen family groups from the periodic table respectively. The valence electrons in boron and chlorine are three and seven respectively.
Key Points To Consider When Drawing The BCl3 Structure
A three-step approach for drawing the BCl3 Lewis structure can be used. The first step is to sketch the Lewis structure of the BCl3 molecule, to add valence electrons around the boron atom; the second step is to add valence electrons to the three chlorine atoms, and the final step is to combine the step1 and step2 to get the BCl3 Lewis Structure.
The BCl3 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the BCl3 molecule. The geometry of the BCl3 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose the BCl3 geometrical shape in which the electrons have from one another.
Finally, you must add their bond polarities to compute the strength of the B-Cl bond (dipole moment properties of the BCl3 molecule). The boron-chlorine bonds in boron trichloride(BCl3), for example, are polarised toward the more electronegative chlorine in BCl3 molecule, and because both bonds have the same size and located around three chlorine terminals of the trigonal planar with no lone pairs of electrons just out of the plan, their sum is zero due to the BCl3 molecule’s bond dipole moment and no lone pairs of electrons on the boron atom. Because each B-Cl bond polarity canceled each other in the BCl3 molecule. The boron trichloride(BCl3) molecule is classified as a nonpolar molecule.
The molecule of boron trichloride(with trigonal planar molecular geometry) is tilted, the bond angles between boron and chlorine are 120 degrees. It has a difference in electronegativity values between boron and chlorine atoms, with boron’s pull being less than chlorine’s terminal in the BCl3 molecule. But they canceled each other due to the symmetrical molecular geometry of BCl3. As a result, it has the zero dipole moment. The BCl3 molecule has a zero dipole moment due to an equal charge distribution of negative and positive charges. The net dipole moment of the BCl3 molecule is 0 D.
Overview: BCl3 Lewis Structure
The central atom is boron, which is bordered on three terminals with three chlorine atoms( in trigonal planar geometry), and no lone pairs of electrons on the boron in the trigonal planar geometry. Boron has three outermost valence electrons, indicating that it possesses three electrons in its outermost shell, whereas chlorine only has seven valence electrons in its outermost shell. To complete the octet of the chlorine atom, a chlorine terminal atom requires one valence electron. If you’re interested in learning more about the chlorine octet rule, please see in our previous post.
Three chlorine atoms establish covalent connections with the central boron atom as a result, leaving the boron atom with no lone pairs. There are no lone pair of electrons on the boron central atom that resist the bond pairs of the three B-Cl. According to VSEPR theory, the bond pairs lead the BCl3 molecule to take on a trigonal planar molecular geometry shape.
The BCl3 molecule’s B-Cl bonds are arranged in symmetrical order around the trigonal planar molecular geometry, giving rise to the BCl3 molecular shape. The BCl3 molecule has a trigonal planar molecular geometry because there is no electrical repulsion between lone pairs and three bond pairs(B-Cl) of the BCl3 molecule.
Electronegative Difference Calculation of BCl3 Molecule:
The boron atom has an electronegativity of 2.04, while chlorine has an electronegativity of 3.16 in the BCl3 molecule. The difference in electronegativity can be estimated using the method below.
The electronegative value difference between boron and chlorine
Electronegativity value of boron = 2.04
Electronegativity value of chlorine= 3.16
Difference of electronegativity value between boron and chlorine= 3.16 – 2.04=1.12Electronegativity difference between B-Cl bond calculation of BCl3 molecule
Due to the difference in electronegativity value of greater than 0.5, the B-Cl bond of the BCl3 molecule becomes polar. Because of this difference in electronegativity, the BCl3 molecule’s B-Cl bond becomes polar. The total net dipole moment of the BCl3 molecule is zero due to the cancellation of the bond dipole moment in the trigonal planar geometry. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of BF3 is discussed in our previous post.
As a result, the B-Cl bond’s dipole moment is high due to the polarization of the bonds and no lone pairs of electrons, and all B-Cl bonds’ dipoles are arranged in the symmetrical BCl3 molecular geometry. The BCl3 molecule’s total dipole moment is predicted to be 0 D. It has a partial negative charge for the terminal chlorine atoms and a partial positive charge for the central boron atom.
The electron dot structure of the BCl3 molecule is also known as the BCl3 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the BCl3 molecule’s bond formation. The outermost valence electrons of the BCl3 molecule must be understood while considering the Lewis structure of the molecule.
The boron atom is the middle element in BCl3 molecular geometry, with three electrons in its outermost valence electron shell, whereas the chlorine atom has seven electrons in its outermost valence electron shell.
The BCl3 molecule has a total of 24 valence electrons as a result of the foregoing above said reasoning. With the core central boron atom, the three terminal with three chlorine atoms forms covalent bonds, leaving the boron atom with no lone pairs of electrons on the top and bottom of trigonal planar geometry.
Because no lone pairs of electrons on the central boron atom create interaction with B-Cl bond pairs. The bond angle of the Cl-B-Cl bond in the trigonal planar molecular geometry is approximately 120 degrees. This angle is greater than the CH4 molecule bond angle due to the no lone pairs of electrons on the BCl3 molecule.
There are two types of bonds in the BCl3 molecule. Due to the resonance structure of the BCl3 molecule creates a double bond and a single bond. The double bond of B-Cl is shorter as compared to the single bond of B-Cl. The B-Cl bond length of the single bond is 175 pm(picometer).
To sketch the BCl3 Lewis structure by following these instructions:
Step-1: BCl3 Lewis dot Structure by counting valence electrons on the boron atom
To calculate the valence electron of each atom in BCl3, look for its periodic group from the periodic table. The halogen and boron families, which are the 17th and 13th groups in the periodic table, are both made up of chlorine and boron atoms. In their outermost shells, chlorine and boron have seven and three valence electrons, respectively.
Because chlorine and boron are members of the periodic table’s halogen and boron family groups, their valence electrons are seven and three, respectively.
Calculate the total number of valence electrons in the BCl3 molecule’s outermost valence shell. The first step is to determine how many electrons are in the BCl3 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the BCl3 Lewis diagram. The BCl3 molecule’s core boron atom can be represented as follows:
Total outermost valence shell electron of boron atom in BCl3= 3
Total outermost valence shell electron of the chlorine atom in BCl3= 7
The BC3 molecule has one central boron and three chlorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for BCl3 Lewis structure( dot structure) = 3+3*7= 24 valence electrons in BCl3.calculation of total valence electron of BCl3 molecule
Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of BCl3. We’ll choose the least electronegative value atom in the BCl3 molecule to place in the center of the BCl3 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.
Step-2: Lewis Structure of BCl3 for counting valence electrons around the terminal chlorine atom
As a result, boron is the first atom in the periodic table’s boron family group. Boron is the first member of the boron family. The electronegative value of the boron atom is lower than that of the chlorine atom in the BCl3 molecule. Furthermore, boron has a three electrons limit since chlorine is the most electronegative element in the BCl3 molecule.
In the BCl3 Lewis structure diagram, the boron atom can be the center atom of the molecule. As a result, central boron in the BCl3 Lewis structure, with all three chlorine arranged in the trigonal planar geometry.
Add valence electrons around the chlorine atom, as given in the figure.
Step-3: Lewis dot Structure for BCl3 generated from step-1 and step-2
Connect the exterior and core central atom of the BCl3 molecule with three single bonds (B-Cl). In this stage, use three chlorine atoms on the outside of the BCl3 molecule to the central boron atom in the middle.
Count how many electrons from the outermost valence shell have been used in the BCl3 structure so far. Each B-Cl bond carries two electrons because each boron atom is connected to three chlorine atoms by three B-Cl bonds. Bond pairings of B-Cl are what they’re called.
So, out of the total of 24 valence electrons available for the BCl3 Lewis structure, we used 6 for the BCl3 molecule’s three B-Cl bonds. The BCl3 molecule has no lone pairs of electrons in the central boron atom. We need to put extra electrons in the molecular geometry of BCl3. Where to place the extra electron in the BCl3 molecule?
Place the valence electrons in the B-Cl bond pairs starting with the core boron, three chlorine, and no lone pairs of electrons in the BCl3 molecule. In the BCl3 Lewis structure diagram, we always begin by introducing valence electrons from the central boron atom(in step1). As a result, wrap around the central boron atom’s bond pair valence electrons first (see figure for step1).
The boron atom in the molecule gets only six electrons around its molecular structure. This central boron atom is octet deficient. BCl3 molecule goes on resonance. A chlorine atom has three pairs of lone pairs of electrons. Due to the back bonding mechanism of B-Cl of the BCl3 molecule, chlorine gives one lone pair of electrons to the bond pairs of B-Cl bond. This makes a single bond into a double bond.
This makes boron negative in charge and chlorine makes positive in charge. The double bond resonated around the BCl3 molecule. The double bond of B-Cl is shorter as compared to the single B-Cl bond. In this way, Boron gets its octet stability.
Boron requires 6 electrons in its outermost valence shell to complete the molecular stability, 6 electrons bond pairs in B-Cl bonds. Then no electrons as a lone pair of electrons on the boron atom of the BCl3 molecule are placed in a trigonal planar geometry. Boron already shares 6 electrons to the three B-Cl bonds. Then place the valence electron in the chlorine atom, it placed around seven electrons(step-2). Totally, 21 valence electrons placed on the three chlorine atoms of the BCl3 molecule.
We’ve positioned 6 electrons around the central chlorine atom(step-3), which is represented by a dot, in the BCl3 molecular structure above. The boron atom completes its molecular stability in the BCl3 molecule because it possesses 6 electrons in its (B-Cl) bond pairs with three chlorine in the outermost valence shell.
Count how many outermost valence shell electrons have been used so far using the BCl3 Lewis structure. Three electron bond pairs are shown as dots in the BCl3 chemical structure, whereas three single bonds each contain two electrons. The outermost valence shell electrons of the BCl3 molecule(bond pairs) are six as a result of the calculation.
So far, we’ve used six of the BCl3 Lewis structure’s total 6 outermost valence shell electrons. No lone pairs of electrons on the boron atom in the trigonal planar of the BCl3 molecule.
Complete the middle boron atom stability and, if necessary, apply a covalent bond. The central boron atom undergoes octet stability(due to resonance structure). Because it has a total of 8 electrons in the outermost valence shell. Eight electrons come from one double bond pair of B-Cl and two single bond pairs of B-Cl on the boron central atom of BCl3.
The core atom in the BCl3 Lewis structure is boron, which is bonded to the three chlorine atoms by single bonds (B-Cl). With the help of three single bonds, it already shares six electrons. As a result, the boron follows the octet rule and has 8 electrons (due to resonance structure) surrounding it on the three terminals of the BCl3 molecule’s trigonal planar geometry.
How to calculate the formal charge on a boron atom in BCl3 Lewis Structure?
The formal charge on the BCl3 molecule’s boron central atom often corresponds to the actual charge on that boron central atom. In the following computation, the formal charge will be calculated on the central boron atom of the BCl3 Lewis dot structure.
To calculate the formal charge on the central boron atom of the BCl3 molecule by using the following formula:
The formal charge on the boron atom of BCl3 molecule= (V. E(B)– L.E(B) – 1/2(B.E))
V.E (B) = Valence electron in a boron atom of BCl3 molecule
L.E(B) = Lone pairs of an electron in the boron atom of the BCl3molecule.
B.E = Bond pair electron in B atom of BCl3 moleculecalculation of formal charge on boron atom in BCl3 molecule
The boron core atom (three single bonds connected to three chlorine atoms ) of the BCl3 molecule has 3 valence electrons, no lone pairs of electrons(zero electrons), and six bonding pairing valence electrons. Put these values for the boron atom in the formula above.
Formal charge on boron atom of BCl3 molecule = (3- 0-(6/2)) =0
In the Lewis structure of BCl3, the formal charge on the central boron atom is zero.
In this post, we discussed the method to construct the BCl3 Lewis structure. First, the valence electrons are placed around the boron atom. Second, place the valence electron on the chlorine atom. Finally, when we combined the first and second steps. It gives BCl3 Lewis structure. Need to remember that, if you follow above said method, you can construct molecular dot structure very easily.
What is the BCl3 Lewis structure?
BCl3 Lewis structure is dot representation
What is the formal charge on the BCl3 Lewis structure?
Zero charge on the BCl3 molecular structure
The polarity of the molecules
The polarity of the molecules are listed as follows
- Polarity of BeCl2
- Polarity of SF4
- Polarity of CH2Cl2
- Polarity of NH3
- Polarity of XeF4
- Polarity of BF3
- Polarity of NH4+
- Polarity of CHCl3
- Polarity of BrF3
- Polarity of BrF5
- Polarity of SO3
- Polarity of SCl2
- Polarity of PCl3
- Polarity of H2S
- polarity of CS2
- Polarity of NO2+
- Polarity of HBr
- Polarity of HCl
- Polarity of CH3F
- Polarity of SO2
- Polarity of CH4
Lewis Structure and Molecular Geometry
Lewis structure and molecular geometry of molecules are listed below
- CH4 Lewis structure and CH4 Molecular geometry
- BeCl2 Lewis Structure and BeCl2 Molecular geometry
- SF4 Lewis Structure and SF4 Molecular geometry
- CH2Cl2 Lewis Structure and CH2Cl2 Molecular geometry
- NH3 Lewis Structure and NH3 Molecular geometry
- XeF4 Lewis Structure and XeF4 Molecular geometry
- BF3 Lewis Structure and BF3 Molecular geometry
- NH4+ Lewis Structure and NH4+ Molecular geometry
- CHCl3 Lewis Structure and CHCl3 Molecular geometry
- BrF3 Lewis Structure and BrF3 Molecular geometry
- BrF5 Lewis Structure and BrF5 Molecular geometry
- SO3 Lewis Structure and SO3 Molecular geometry
- SCl2 Lewis structure and SCl2 Molecular Geometry
- PCl3 Lewis structure and PCl3 Molecular Geometry
- H2S Lewis structure and H2S Molecular Geometry
- NO2+ Lewis structure and NO2+ Molecular Geometry
- HBr Lewis structure and HBr Molecular Geometry
- CS2 Lewis structure and CS2 Molecular Geometry
- CH3F Lewis structure and CH3F Molecular Geometry
- SO2 Lewis structure and SO2 Molecular Geometry
- HCl Lewis structure and HCl Molecular Geometry
- HF Lewis structure and HF Molecular Geometry
- HI Lewis structure and HI Molecular Geometry
- CO2 Lewis structure and CO2 Molecular Geometry
- SF2 Lewis structure and SF2 Molecular Geometry
- SBr2 Lewis structure and SBr2 Molecular Geometry
- PF3 Lewis structure and PF3 Molecular Geometry
- PBr3 Lewis structure and PBr3 Molecular Geometry
- CH3Cl Lewis structure and CH3Cl Molecular Geometry
- CH3Br Lewis structure and CH3Br Molecular Geometry
- CH3I Lewis structure and CH3I Molecular Geometry
- SCl4 Lewis structure and SCl4 Molecular Geometry
- SBr4 Lewis structure and SBr4 Molecular Geometry
- CH2F2 Lewis structure and CH2F2 Molecular Geometry
- CH2Br2 Lewis structure and CH2Br2 Molecular Geometry
- XeCl4 Lewis structure and XeCl4 Molecular Geometry