SeO Lewis structure

SeO has one selenium atom and one oxygen atom.

In SeO Lewis structure, there is a double bond between the selenium and oxygen atom, and on both selenium and oxygen atoms, there are two lone pairs.

Contents

Steps

Use these steps to correctly draw the SeO 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, both selenium and oxygen lie in group 16.

Hence, both selenium and oxygen have six valence electrons.

Since SeO has one selenium atom and one oxygen atom, so…

Valence electrons of one selenium atom = 6 × 1 = 6
Valence electrons of one oxygen atom = 6 × 1 = 6

And the total valence electrons = 6 + 6 = 12

• 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

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

Since selenium is less electronegative than oxygen, assume that the central atom is selenium.

• And finally, draw the rough sketch

#2 Mark lone pairs on the atoms

Here, we have a total of 6 electron pairs. And one Se — O bond is already marked. So we have to only mark the remaining five electron pairs as lone pairs on the sketch.

Also remember that selenium is a period 4 element, so it can keep more than 8 electrons in its last shell. And oxygen is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atom is oxygen.

So for oxygen, there are three lone pairs, and for selenium, there are two lone pairs.

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 selenium atom, formal charge = 6 – 4 – ½ (2) = +1

For oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

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

The above structure is not a stable Lewis structure because both selenium and oxygen 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 oxygen atom to make a new Se — O bond with the selenium atom as follows:

In the above structure, you can see that the central atom (selenium) forms an octet. And the outside atom (oxygen) also forms 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 SeO.