Lewis structure of CH2N2

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The Lewis structure of CH₂N₂ contains two single bonds and two double bonds, with carbon in the center, and two hydrogens and two nitrogens on either side. There are two lone pairs on the right nitrogen atom, and the left nitrogen atom, carbon atom, and hydrogen atom do not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of CH₂N₂.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Complete octet on atoms
#5 Calculate formal charge and check stability

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… carbon is a group 14 element, hydrogen is a group 1 element, and nitrogen is a group 15 element. Hence, carbon has four valence electrons, hydrogen has one valence electron, and nitrogen has five valence electrons.

Now CH₂N₂ has one carbon atom, two hydrogen atoms, and two nitrogen atoms.

So the total number of valence electrons = valence electrons of carbon atom + (valence electrons of hydrogen atom × 2) + (valence electrons of nitrogen atom × 2)

Therefore, the total number of valence electrons = 4 + 2 + 10 = 16

• Now decide the central atom

We can not assume hydrogen as 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.

Therefore, choose the central atom from carbon and nitrogen.

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for carbon and nitrogen as follows:

Electronegativity value of carbon = 2.55
Electronegativity value of nitrogen = 3.04

Obviously, carbon is less electronegative than nitrogen. Hence, assume that carbon is the central atom.

So now, put carbon in the center and two hydrogens and two nitrogens on either side. And draw the rough skeleton structure for the Lewis structure of CH₂N₂ something like this:

Also read: How to draw Lewis structure of KrF₂ (4 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since carbon is surrounded by two hydrogens and two nitrogens, use eight electrons to show four chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 16 valence electrons. And in the above structure, we have already used eight valence electrons. Hence, eight valence electrons are remaining.

Two valence electrons represent one lone pair. So eight valence electrons = four lone pairs.

Note that both (carbon and nitrogen) 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.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are hydrogens and nitrogens. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.

So right nitrogen will get three lone pairs, and left nitrogen will get one lone pair. And the central atom (carbon) will not get any lone pair, because all four lone pairs are used.

Now draw the Lewis structure of CH₂N₂ something like this:

In the above structure, you can see that the octet is completed on outside atoms (except left nitrogen). Also, the central atom (carbon) doesn’t form an octet.

So in the next step, we have to complete the octet on carbon and left nitrogen.

Also read: How to draw Lewis structure of N₂F₂ (5 steps)

#4 Complete octet on atoms

Remember that both (carbon and nitrogen) are the period 2 elements, so they can not keep more than 8 electrons in their last shell.

Now carbon already has six valence electrons. Hence, carbon needs two more valence electrons to complete its octet.

So convert one lone pair from the left nitrogen atom to make a new bond with the carbon atom. And then, the Lewis structure of CH₂N₂ looks something like this:

Now convert one lone pair from the right nitrogen atom to make a new bond with the left nitrogen atom. And then, the Lewis structure of CH₂N₂ looks something like this:

In the above structure, you can see that the octet is completed on the central atom (carbon), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of XeOF₄ (5 steps)

#5 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For carbon atom

Valence electrons = 4
Nonbonding electrons = 0
Bonding electrons = 8

Formal charge = 4 – 0 – ½ (8) = 0

• For each hydrogen atom

Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2

Formal charge = 1 – 0 – ½ (2) = 0

• For left nitrogen atom

Valence electrons = 5
Nonbonding electrons = 0
Bonding electrons = 8

Formal charge = 5 – 0 – ½ (8) = +1

• For right nitrogen atom

Valence electrons = 5
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 5 – 4 – ½ (4) = -1

Mention the formal charges of atoms on the structure. So the Lewis structure of CH₂N₂ looks something like this:

In the above structure, you can see that the formal charges of atoms are closer to zero. Therefore, this is the most stable Lewis structure of CH₂N₂.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Related

• Lewis structure of KrF₂
• Lewis structure of N₂F₂
• Lewis structure of XeOF₄
• Lewis structure of BrCl₃
• Lewis structure of CSe₂

External links

• What is the correct Lewis structure of diazomethane? – Chemistry Stack Exchange
• CH2N2 Lewis Structure & Characteristics (15 Helpful Facts) – Lambda Geeks
• CH2N2 Lewis Structure, Molecular Geometry, Hybridization, and Polarity – Techiescientist
• Which is an acceptable Lewis structure for diazomethane? – Homework.Study.com
• Draw the lewis structure of CH2N2, including formal charges and reasonable resonance structures, if any – Chegg
• Lewis structure of CH2N2 – Reddit
• Draw the Lewis structure (including resonance structures) for diazomethane (CH2N2) – Brainly
• Draw the Lewis structure of diazomethane (CH2N2) that contains a formal charge on carbon and nitrogen – Numerade
• Draw the Lewis structure (including resonance structures) for diazomethane (CH2N2) – Course Hero
• Draw the Lewis structure of diazomethane (CH2N2) that contains a formal charge on carbon and nitrogen – Bartleby
• What is the correct Lewis structure of diazomethane? – ECHEMI