CH3OCH3 (dimethyl ether) has two carbon atoms, six hydrogen atoms, and one oxygen atom.
In the CH3OCH3 Lewis structure, there are two single bonds around the oxygen atom, with two carbon atoms attached to it, and each carbon is attached with three hydrogen atoms. And on the oxygen atom, there are two lone pairs.
Steps
Use these steps to correctly draw the CH3OCH3 Lewis structure:
#1 First draw a rough sketch
#2 Mark lone pairs on the atoms
#3 Calculate and mark formal charges on the atoms, if required
Let’s discuss each step in more detail.
#1 First draw a rough sketch
- First, determine the total number of valence electrons
In the periodic table, carbon lies in group 14, hydrogen lies in group 1, and oxygen lies in group 16.
Hence, carbon has four valence electrons, hydrogen has one valence electron, and oxygen has six valence electrons.
Since CH3OCH3 has two carbon atoms, six hydrogen atoms, and one oxygen atom, so…
Valence electrons of two carbon atoms = 4 × 2 = 8
Valence electrons of six hydrogen atoms = 1 × 6 = 6
Valence electrons of one oxygen atom = 6 × 1 = 6
And the total valence electrons = 8 + 6 + 6 = 20
Learn how to find: Carbon valence electrons, Hydrogen valence electrons, and Oxygen valence electrons
- Second, find the total electron pairs
We have a total of 20 valence electrons. And when we divide this value by two, we get the value of total electron pairs.
Total electron pairs = total valence electrons ÷ 2
So the total electron pairs = 20 ÷ 2 = 10
- Third, determine the central atom
Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.
Now we have to choose the central atom from carbon and oxygen. Place the least electronegative atom at the center.
Since carbon is less electronegative than oxygen, assume that the central atom is carbon.
Here, there are two carbon atoms, so we can assume any one as the central atom.
Let’s assume that the central atom is right carbon.
Therefore, place carbons in the center and hydrogen and oxygen on either side.
- And finally, draw the rough sketch
#2 Mark lone pairs on the atoms
Here, we have a total of 10 electron pairs. And eight bonds are already marked. So we have to only mark the remaining two electron pairs as lone pairs on the sketch.
Also remember that both (carbon and oxygen) are the period 2 elements, so they can not keep more than 8 electrons in their last shell. And hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell.
Always start to mark the lone pairs from outside atoms. Here, the outside atoms are hydrogens and oxygen. But no need to mark on hydrogen, because each hydrogen has already two electrons.
So for oxygen, there are two lone pairs, and for carbon, there is zero lone pair because all two electron pairs are over.
Mark the lone pairs on the sketch as follows:
#3 Calculate and mark formal charges on the atoms, if required
Use the following formula to calculate the formal charges on atoms:
Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons
For each carbon atom, formal charge = 4 – 0 – ½ (8) = 0
For each hydrogen atom, formal charge = 1 – 0 – ½ (2) = 0
For oxygen atom, formal charge = 6 – 4 – ½ (4) = 0
Here, the atoms do not have charges, so no need to mark the charges.
In the above structure, you can see that the central atom (right carbon) forms an octet. The outside atoms (left carbon and oxygen) also form an octet, and all hydrogens form a duet. Hence, the octet rule and duet rule are satisfied.
Therefore, this structure is the stable Lewis structure of CH3OCH3.
Next: HCOOH Lewis structure
External links
- https://techiescientist.com/ch3och3-lewis-structure/
- https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/CH3OCH3-lewis-structure.html
Deep
Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.