BrO- Lewis Structure & Characteristics (11 Important Facts)

Hypobromite ion or alkaline bromine water is denoted by the chemical formula BrO-. Let us discuss about BrO- and it’s complete facts.

BrO- or hypobromite ion is formed by the rapid reaction between bromine and Aqueous alkali like sodium hydroxide or potassium hydroxide. The oxidation state of bromine is +1 in BrO-. Its molar mass is 95.904 g/mol with character similar to hypochlorite.

The conjugate acid of this anion is hypobromous acid. Let us discuss about lewis structure, valence electrons, resonance in BrO-ion in the following sections.

How to Draw BrO- Lewis Structure ?

Lewis structure representation helps us to understand the bonding and lone pairs in a compound in a very easy manner. Let us know about drawing the Lewis structure of BrO-.

Computing total valence electrons

Bromine and oxygen has seven and six electrons respectively. In addition to this there is a negative charge. So total 7+6+1= 14 electrons.

Drawing the skeletal structure

Bromine being the least electronegative atom will be central atom attached with oxygen.

Making of bonds and distribution of electrons

A bond is made in between oxygen and bromine. Then the rest of twelve electrons are distributed among the two atoms by satisfying its octet.

bro- lewis structure
Lewis Structure of BrO-

BrO-Lewis Structure Shape

The shape of any molecule can be easily predicted through VSEPR theory. Let us see the shape of BrO-.

The shape of BrO-ion is linear. Since it has two atoms separated with a single bond it’s molecular geometry is linear. While considering its electronic geometry it have tetrahedral geometry.

BrO- Lewis structure Formal Charge

A compound with least formal charge value will be stable. Let us calculate the formal charge of BrO-.

The formal charge of BrO- is -1. So it is not zero in the case of hypobromite ion.

The equation of calculating Formal Charge is

• Formal charge= valence electrons- No. Of bonds -non bonded electrons
• Formal charge of bromine =7-1-6=0
• Formal charge of oxygen= 6-1-6=-1

BrO-Lewis Structure Angle

The angle of a compound can be different when there is lone pairs and not. Let us see the angle of BrO-.

The bond angle of BrO-is 1800. BrO-is a AXE3 type molecule. When considering its molecular geometry its shape is linear with angle 1800 . But when it’s looking in its electronic geometry it can have tetrahedral geometry with 1090.

BrO- Lewis Structure Octet Rule

Octet rule implies that every atom have eight electrons in its valence shell after bond formation. Let us discuss about the octet in BrO-.

BrO-ion obeys octet rule. The total valence electrons in BrO-is 14 filled by satisfying their octet. Bromine with seven and oxygen with six gets eight electrons after their bond making. So both the atom obeys its octet.

BrO- Lewis Structure Lone Pairs

Lone pairs usually don’t involve in bond making but has significant role in shape determination. Let us know about the lone pairs in BrO-.

The lone pairs present in BrO-is six. Bromine and oxygen has three lone pairs in them. So total six lone pairs or twleve non bonding electrons seen in BrO-.

BrO- Valence Electrons

The valence electrons play a crucial role in bonding process. Let us calculate the valence electrons in BrO-.

BrO-has fourteen valence electrons in them. Bromine has seven and oxygen has six valence electrons in them. So there are 13 electrons. Adding the additional negative charge gives fourteen valence electrons.

BrO- Hybridization

Orbitals with and without electrons involve in hybridization process to generate new set of orbitals. Let us study about the hybridisation in BrO-.
The hybridisation of BrO-is sp3. One s and three p orbitals of bromine overlaps to form four sp3 hybrid orbitals. In which three orbitals are completely filled and other is partially filled.

The partially filled p orbital overlapps with the p orbital of oxygen to form a stable bond. The shape is tetrahedron featuring three corners occupied with lone pairs.

Is BrO- Polar or Non Polar?

Polarity is dependent on the symmetry and electronegativity of a compound. Let us check whether BrO-is polar or not.

BrO- is a polar compound. Polar nature of a compound can be easily predicted through the knowing it’s electronegativity difference. When the electronegativity is greater than 0.4 for a compound then it will be polar.

Why and How BrO-is Polar?

The electronegativity of bromine is 2.96 and oxygen is 3.44. Their electronegativity difference is found to be 0.48 which is greater than 0.4 . That means the Compound is polar in nature. The negative charge associated with the compound also implies that it is a polar compound.

Is BrO- Electrolyte?

Electrolyte usually dissociate into ions when dissolved in water and conduct electricity. Let us check whether BrO-is electrolyte or not.

BrO-is an electrolyte. It will undergo dissociation when dissolved in water to electricity.When BrO-is dissolved in water it dissociates to form hydrogen oxybromide, HOBr and hydroxide ion, OH- .

Being a charged ion hydroxide ion will move across to conduct electricity. In addition to this BrO-itself being a charged compound can also conduct electricity.

Is BrO- Ionic or Covalent?

Ionic compounds are associated with charged ions while covalent are not. Let us see BrO-is ionic or covalent.

BrO- is a covalent compound. Even though there is electronegative oxygen present here with an additional charge doesn’t makes it a covalent compound.When the electronegativity difference of two atoms are greater than 2.1 then it will be ionic compound.

Here the electronegativity difference is 0.48 which indicates the compound is covalent with polar nature.Also the bond between Br and O is made by mutual sharing of electrons like covalent compounds do. So BrO- covalent compound.


Hypobromite ion or BrO- is useful as a germicide in spas and hot tubs. It can be used in common bleaching purposes. It is also found in our immune cells.

Aparna Dev

Hi... I am Aparna Dev, a chemistry Postgraduate with a good understanding of chemistry concepts. I am working in Kerala Minerals and Metals Limited Kollam with experience in the development of electrocatalysts as a part of post graduate thesis. Let's connect through LinkedIn-

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