Carbon monoxide (CO) Molecule Lewis Structure
Carbon monoxide (CO) is a diatomic molecule and contains one carbon atom and one oxygen atom. Lewis structure of CO molecule contains a triple bond between those two atoms. Both Carbon and Oxygen atoms have one lone pair in their valence shells.
Lewis structure of Carbon monoxide (CO) molecule
In the lewis structure of carbon monoxide, both atoms have eight electrons in their valence shells. However, oxygen atoms has a +1 charge and carbon atom has a -1 charge. In next sections, we will draw CO lewis structure step by step.
Carbon monoxide
Carbon monoxide is a very toxic gaseous molecule at room temperature and formed due to incomplete combustion of products (Due to lack of oxygen gas). You should never try to get exposed to this carbon monoxide gas. However, carbon monoxide is easily oxidized to carbon dioxide gas in the presence of oxygen gas.
Now, we will learn how to draw the carbon monoxide lewis structure step by step.
Steps of drawing lewis structure of CO molecule
There are guidelines (several steps) to draw a lewis structure. Number of steps can be changed according the complexity of the molecule or ion. Whether CO molecule seems as a simple molecule, there are important things to consider drawing the lewis structure. However those all steps are mentioned and explained in detail in this tutorial for your knowledge.
- Find total number of electrons of the valance shells of carbon and oxygen atoms
- Total electrons pairs existing as lone pairs and bonds
- Center atom selection
- Mark lone pairs on atoms
- Mark charges on atoms if there are charges.
- Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.
Total number of electrons of the valance shells of CO molecule
Carbon is a group IVA element in the periodic table and contains four electrons in its last shell. Carbon is a group VIA element in the periodic table and contains six electrons in its last shell. Now, we know how many electrons are there in valence shells of carbon and oxygen atoms.
- valence electrons given by carbon atoms = 4 * 1 = 4
- valence electrons given by oxygen atoms = 6 * 1 = 6
- Total valence electrons = 10
Total valence electrons pairs
Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells
Total electron pairs are determined by dividing the number total valence electrons by two. For, CO molecule, Total pairs of electrons are five in their valence shells.
Center atom selection of CO molecule
Center atom selection in lewis structure drawing can be a long process if a molecule is complex. Because, there are only two atoms in carbon monoxide molecule, we do not need to worry much about center atom selection. Therefore, just draw a single bond between carbon atom and oxygen atom.
Lone pairs on atoms
After determining the center atom and sketch of CO molecule, we can start to mark lone pairs on atoms. Remember that, there should be total of five electron pairs as lone pairs and bonds.
- There is already one bond in the drawn sketch. So, there are four remaining lone pairs to mark on carbon and oxygen atoms.
- Because, there is no center atom, we can start to mark remaining lone pairs on oxygen atom. Oxygen atom will take three lone pairs.
- Now, one valence electron pair is remaining and it is marked on carbon atom.
Mark charges on atoms
There are charges on carbon and oxygen atoms to mark in the above structure. Marking of charges on atoms is a compulsory step to decide the stability of a molecule.
Check the stability and minimize charges on atoms by converting lone pairs to bonds
Because, there are charges on carbon and oxygen atoms. Also octal is not completed in carbon atom. Therefore, above structure is not stable and need to convert a lone pair on oxygen atoms to a bond as below.
However above structure is still unstable because octal is not still completed in carbon atom. So, we need to convert one more lone pair on oxygen atom to a bond. Then, there will be a triple bond between carbon and oxygen atoms. But, there will be +1 charge on oxygen atom and -1 charge on carbon atom.
Questions and Answers
What are the differences of lewis structures of CO and CO2?
In the lewis structure of CO, there is a lone pair on Carbon atom. But in CO2 lewis structure, there is no a lone pair on Carbon atom. Also, there are four bonds around the carbon atom in CO2.
Are there a triple bond in CO molecule
Yes. According to the most stable lewis structure of CO, there is a triple bond between Carbon atom and Oxygen atom.
What is the special thing of CO lewis structure considering the charges?
There is a +1 charge on Oxygen atom. Oxygen is more electronegative than Carbon atom. Usually, negative charge should be on the Oxygen atom. But, as a special case, +1 charge is on the oxygen atom.