C2N2 Lewis structure

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C₂N₂ (cyanogen) has two carbon atoms and two nitrogen atoms.

In C₂N₂ Lewis structure, there is a single bond between the two carbon atoms, and each carbon is attached with one nitrogen atom, and on each nitrogen atom, there is one lone pair.

Steps

Use these steps to correctly draw the C₂N₂ 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
#4 Convert lone pairs of the atoms, and minimize formal charges
#5 Repeat step 4 if needed, until all charges are minimized, to get a stable Lewis structure

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, and nitrogen lies in group 15.

Hence, carbon has four valence electrons and nitrogen has five valence electrons.

Since C₂N₂ has two carbon atoms and two nitrogen atoms, so…

Valence electrons of two carbon atoms = 4 × 2 = 8
Valence electrons of two nitrogen atoms = 5 × 2 = 10

And the total valence electrons = 8 + 10 = 18

Learn how to find: Carbon valence electrons and Nitrogen valence electrons

• Second, find the total electron pairs

We have a total of 18 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 = 18 ÷ 2 = 9

• Third, determine the central atom

We have to place the least electronegative atom at the center.

Since carbon is less electronegative than nitrogen, 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 left carbon.

Therefore, place carbons in the center and nitrogens on either side.

• And finally, draw the rough sketch

#2 Mark lone pairs on the atoms

Here, we have a total of 9 electron pairs. And three bonds are already marked. So we have to only mark the remaining six electron pairs as lone pairs on the sketch.

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

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are nitrogens and right carbon.

So for each nitrogen, there are three lone pairs, for both carbons, there is zero lone pair because all six 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 (4) = +2

For each nitrogen atom, formal charge = 5 – 6 – ½ (2) = -2

Here, both carbon and nitrogen atoms have charges, so mark them on the sketch as follows:

The above structure is not a stable Lewis structure because both carbon and nitrogen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.

#4 Convert lone pairs of the atoms, and minimize formal charges

Convert a lone pair of the left nitrogen atom to make a new C — N bond with the left carbon atom as follows:

#5 Repeating step 4 to get a stable Lewis structure

Since there are charges on carbon and nitrogen atoms, again convert a lone pair of the left nitrogen atom to make a new C — N bond with the left carbon atom as follows:

#6 Minimize charges again

There are still charges on carbon and nitrogen atoms, so convert a lone pair of the right nitrogen atom to make a new C — N bond with the right carbon atom as follows:

#7 Minimize charges again

The carbon and nitrogen atoms still have charges, so again convert a lone pair of the right nitrogen atom to make a new C — N bond with the right carbon atom as follows:

In the above structure, you can see that the central atom (left carbon) forms an octet. And the outside atoms (right carbon and nitrogens) also form an octet. Hence, the octet rule is satisfied.

Also, the above structure is more stable than the previous structures. Therefore, this structure is the stable Lewis structure of C₂N₂.

Next: TeF₆ Lewis structure

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External links

• https://homework.study.com/explanation/draw-the-lewis-structure-for-c2n2-what-is-its-molecular-geometry.html
• https://oneclass.com/homework-help/chemistry/7041489-c2n2-lewis-structure.en.html
• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-c2n2-formal-charge-atom-q26401128
• https://www.answers.com/Q/Lewis_structure_for_compound_C2N2