CH2NH Lewis structure

CH₂NH (methylene imine) has one carbon atom, three hydrogen atoms, and one nitrogen atom.

In the CH₂NH Lewis structure, there is a double bond between the carbon and nitrogen atom. The carbon atom is attached with two hydrogen atoms, and the nitrogen atom is attached with one hydrogen atom. And on the nitrogen atom, there is one lone pair.

Alternative method: Lewis structure of CH₂NH

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 nitrogen lies in group 15.

Hence, carbon has four valence electrons, hydrogen has one valence electron, and nitrogen has five valence electrons.

Since CH₂NH has one carbon atom, three hydrogen atoms, and one nitrogen atom, so…

Valence electrons of one carbon atom = 4 × 1 = 4
Valence electrons of three hydrogen atoms = 1 × 3 = 3
Valence electrons of one nitrogen atom = 5 × 1 = 5

And the total valence electrons = 4 + 3 + 5 = 12

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

• Second, find the total electron pairs

We have a total of 12 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 = 12 ÷ 2 = 6

• 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 nitrogen. Place the least electronegative atom at the center.

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

Therefore, place carbon in the center and hydrogen and nitrogen on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 6 electron pairs. And four 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 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.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are hydrogens and nitrogen. But no need to mark on hydrogen, because each hydrogen has already two electrons.

So for nitrogen, 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:

Formal charge

Use the following formula to calculate the formal charges on atoms:

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

For carbon atom, formal charge = 4 – 0 – ½ (6) = +1

For each hydrogen atom, formal charge = 1 – 0 – ½ (2) = 0

For nitrogen atom, formal charge = 5 – 4 – ½ (4) = -1

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.

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

Final structure

The final structure of CH₂NH consists of a carbon atom and a nitrogen atom connected by a double covalent bond. In this arrangement, the carbon atom is bonded to two hydrogen atoms, and the nitrogen atom is bonded to one hydrogen atom. To satisfy the octet rule, the carbon atom utilizes four bonding electrons (two for the double bond and one for each hydrogen), while the nitrogen atom maintains one lone pair in addition to its three bonding electrons. Every atom in this configuration—the carbon, nitrogen, and all three hydrogens—carries a formal charge of zero, which represents the most stable and energetically favorable state for the molecule. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of methanimine.

Next: HClO₄ Lewis structure

External links

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