# SiO Lewis structure

SiO (silicon monoxide) has one silicon atom and one oxygen atom.

In SiO Lewis structure, there is a triple bond between the silicon and oxygen atom, and on both silicon and oxygen atoms, there is one lone pair.

Also, there is a negative (-1) charge on the silicon atom, and a positive (+1) charge on the oxygen atom.

Contents

## Steps

Here’s how you can draw the SiO Lewis structure step by step:

#1 Draw a rough sketch
#2 Mark lone pairs on the atoms
#3 Mark charges on the atoms
#4 Minimize charges by converting lone pairs
#5 If central atom doesn’t form octet, convert lone pair and mark charges again

Let’s break down each step in detail.

### #1 Draw a rough sketch

• First, determine the total number of valence electrons

In the periodic table, silicon lies in group 14, and oxygen lies in group 16.

Hence, silicon has four valence electrons and oxygen has six valence electrons.

Since SiO has one silicon atom and one oxygen atom, so…

Valence electrons of one silicon atom = 4 × 1 = 4
Valence electrons of one oxygen atom = 6 × 1 = 6

And the total valence electrons = 4 + 6 = 10

• Second, find the total electron pairs

We have a total of 10 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 = 10 ÷ 2 = 5

• Third, determine the central atom

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

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

• And finally, draw the rough sketch

### #2 Mark lone pairs on the atoms

Here, we have a total of 5 electron pairs. And one Si — O bond is already marked. So we have to only mark the remaining four electron pairs as lone pairs on the sketch.

Also remember that silicon is a period 3 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 silicon, there is one lone pair.

Mark the lone pairs on the sketch as follows:

### #3 Mark charges on the atoms

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

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

For silicon atom, formal charge = 4 – 2 – ½ (2) = +1

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

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

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

### #4 Minimize charges by converting lone pairs

Convert a lone pair of the oxygen atom to make a new Si — O bond with the silicon atom as follows:

In the above structure, you can see that the central atom (silicon) doesn’t form an octet. Hence, the octet rule is not satisfied.

### #5 Convert lone pair and mark charges again

Therefore, again convert a lone pair of the oxygen atom to make a new Si — O bond with the silicon atom. Also, we have to again check whether there are charges on atoms or not.

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

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

For silicon atom, formal charge = 4 – 2 – ½ (6) = -1

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

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

In the above structure, you can see that the central atom (silicon) forms an octet. And the outside atom (oxygen) also forms an octet. Hence, the octet rule is satisfied.

The formal charges on atoms are closer to zero. Also, the above structure is more stable than the previous structures. Therefore, this structure is the most stable Lewis structure of SiO.

Next: AlI3 Lewis structure