Cobr2 lewis structure, Characteristics: 13 facts you should know

In this article we going to discuss about cobr2 lewis structure including its characteristics and structure and 13 most important facts regarding this.

Cobr2 which is commonly known as bromophosgene in analogy with phosgene. It is produced in fire extinguishers, when halon compounds are decomposed.  It is a colourless liquid with a molar mass of 187.818 gm/mol. It starts boiling at 64.50c, when it decomposes. Even at low temperature, it slowly decomposes to poisonous co and elemental br.

Cobr2 Lewis Structure Drawing

In cobr2 the central atom is C atom in which O and 2 Br atoms are attached. In cobr2, central c atom uses sp2 hybrid orbital. In the ground state, C atom has 4 valance electron but only 2 remains unpaired. To form cobr2, 4 unpaired electrons is required.

When some energy is applied, one 2s electron of c atom becomes unpaired and total 4 unpaired electron is present now. Hence 2 br atoms form 2 sigma bonds and o atom forms 1 sigma as well as 1 pi bond with central c atom. All these are covalent bonds. This is because all these are formed by sharing of electrons between 2 atoms.

cobr2 lewis structure
Cobr2 lewis structure

Cobr2 Lewis Structure Shape

From VSEPR theory we can assume that the shape of cobr2 is trigonal planner. In this structure central carbon atom is surrounded by 2 br atoms and 1 o atom in trigonal planner manner.

The structure of cobr2 does not contain any lone pair of electron on central c atom; hence distortion of ideal trigonal planner structure does not occur. In cobr2, central C atom uses sp2 hybrid orbital to form 2 c-br bonds and 1 c=o bond. As cobr2 has planner structure all the atoms in cobr2 lie in the same plane.

Cobr2 Lewis Structure Formal Charges

The formula we used to calculate the formal charge is -Formal Charge (f.c) on each atom= (Total No of valance electrons of the atom)-(Total no of bonding electron formed by that atom)/2- (total no of nonbonding electrons on that atom).

Hence formal charge on the central c atom in bromophosgene =4-8/2-0=0.

Formal charge on oxygen atom in cobr2=6-4/2-4=0.

Formal charge on 2 terminal br atoms in cobr2=7-2/2-6=0.

Hence formal charge on central C atom in cobr2 is 0 and each bromine atoms and also O atom has formal charge of 0, making the overall compound is electrically neutral.

Cobr2 lewis Structure Lone Pairs

Total No of unshared pair of electron exist on any atom= the valance electrons present on the atom-total no of bonds formed by that particular atom.

In cobr2 lone pair present on central c atom= 4-4=0 i.e. No lone pair of electron on c atom.

Lone pair present on oxygen atom in cobr2=6-2=4 i.e. 2 lone pair of electron.

Lone pair present on br atoms in cobr2= 7-1=6 i.e.3 unshared pair of electron.

These unshared pair of electrons on o and terminal br atoms is shown in the cobr2 lewis structure as electron dots.

Cobr2 Hybridization

Hybridization is a process in which central c atom in cobr2 mixes its atomic orbital to form hybrid orbitals because higher energy atomic orbitals does not take part in bonding. In the ground phase, C has 4 valance electrons out of which only 2 electrons are unpaired. But this is not enough electrons to form cobr2.

Hence when C absorbs hybridization energy, its 2s electron becomes unpaired and requirement of 4 unpaired electron becomes fulfilled. By using this electron C atom forms Cobr2 with the help of 3 sigma bonds and 1 pi bond. In cobr2, c uses sp2 hybrid orbital to make c-br and c=o bonds. According to sp2 hybridization, the structure of cobr2 is trigonal planner.

cobr2 lewis structure
Cobr2 Hybridization

Cobr2 solubility

Cobr2 is soluble in polar solvents because of the fact that as cobr2 is polar in nature, it like to dissolve in polar solvents like water, ethanol, methanol etc. In 100 ml of water, approx 66.7 gm cobr2 dissolved at about 590c.

Cobr2 valance electrons

To calculate the total no of valance electron in cobr2, it is required to know the valance electron of c,o and br atoms. The valance electron present in c atom is 4. The valance electron present in O and Br atom is 6 and 7 respectively. The total no of valance electron present in cobr2 is sum of valance electron of c,o and br atoms i.e. (4*1+6*1+7*2)=24.

Cobr2 lewis structure angle

In cobr2, central c atom is sp2 hybridized and the structure of cobr2 is trigonal planner. According to VSEPR theory, the angle prsent in trigonal planner shape is 1200. Hence the angle between br-C-br and br-C-O is exactly 1200.

Cobr2 lewis Structure Resonance

In Cobr2 resonance occurs and in resonance process nonbonding electron pair shifts from one atom into another atom through conjugation. The structure we get through delocalization is called resonating structure.

When resonance takes place in cobr2, we get 3 equivalent resonating structure and delocalization occurs through conjugation of nonbonding electron pair with carbonyl group in its ∏* orbital.

Cobr2 Resonance

Cobr2 lewis structure Octet Rule

When we see the lewis structure of cobr2 we find that each bromine atom has 8 electrons in the outermost shell and satisfy octet rule. In cobr2 compound central carbon atom forms 2 C-Br bonds and 1 C=O bond making a total of 4 electron pair i.e. 8 electrons around central C atom.

O atom forms 2 bond with central C atom and also contain 2 lone pairs making a total of 8 electrons around O atom. 2 Br atoms form 1 sigma bond each with C atom and both contains 3 lone pair of electron i.e. octet rule is also satisfied for Br atom.

Cobr2 Polar Or Nonpolar?

SOCl2 is a non-polar compound. In cobr2, c=o bond moment lies towards more electronegative o atom. 2 c-br bond moments lie towards Br atom, as br is more electronegative than c atom. All these bond moments cancel each other and hence making the dipole moment of this compound is 0 Debye.

Is cobr2 ionic?

Cobr2 is an ionic compound. This is due to the fact that the electronegativity difference between the C-Br bonds and C=O bond. Cobr2 is soluble in water like ionic compounds do. It has also high melting as well as boiling point similar to that of ionic compound. It also conducts electricity in molten as well as in solution state.

Is cobr2 acidic or basic?

Cobr2 is amphoteric in nature i.e. it is act as an acid or as a base. When cobr2 reacts with acid, it accepts H+ ion through the donation of O atom and act like a like base. When it reacts with base, OH- donates its lone pair of electron and cobr2 accepts this electron and act as a lewis base.

Is cobr2 tetrahedral?

Cobr2 attains trigonal planner geometry in which c atom act as the central atom. It has no tetrahedral geometry, because central c atom is not sp3 hybridized.

Is cobr2 linear?

Cobr2 is not linear because central c atom is not sp hybridized. As the central c atom in cobr2 acquires sp2 and does not attain 1800 hence, question of cobr2 has linear geometry does not arises.

Is cobr2 symmetrical or asymmetrical?

Cobr2 is symmetrical in nature. This is because of the fact that a mirror plane i.e. sigma plane cut the cobr2 compound into 2 symmetrical halves. The sigma plane passes through the carbonyl group. It also contains c2 axis which passes through C=O group, after this operation br is superimposable with another br group.


Cobr2 is a stable compound in which central C atom is sp2 hybridized and due to absence of lone pair of electron the structure is real trigonal planner. In this compound all the atoms satisfied their octet.

Susanta Maity

Hi....I am Susanta Maity. I have completed my Masters from Vidyasagar university with a specialization in organic chemistry. I love to write complicated Chemistry concepts in understandable and simple words. Let's connect through LinkedIn:

Recent Posts