TeO3 Lewis structure

TeO3 Lewis Structure
TeO3 Lewis structure | Image: Learnool

TeO3 (tellurium trioxide) has one tellurium atom and three oxygen atoms.

In TeO3 Lewis structure, there are three double bonds around the tellurium atom, with three oxygen atoms attached to it, on each oxygen atom, there are two lone pairs.

Rough sketch

  • First, determine the total number of valence electrons
Periodic table | Image: Learnool

In the periodic table, both tellurium and oxygen lie in group 16.

Hence, both tellurium and oxygen have six valence electrons.

Since TeO3 has one tellurium atom and three oxygen atoms, so…

Valence electrons of one tellurium atom = 6 × 1 = 6
Valence electrons of three oxygen atoms = 6 × 3 = 18

And the total valence electrons = 6 + 18 = 24

  • Second, find the total electron pairs

We have a total of 24 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 = 24 ÷ 2 = 12

  • Third, determine the central atom

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

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

Therefore, place tellurium in the center and oxygens on either side.

  • And finally, draw the rough sketch
TeO3 Lewis Structure (Step 1)
Rough sketch of TeO3 Lewis structure | Image: Learnool

Lone pair

Here, we have a total of 12 electron pairs. And three Te — O bonds are already marked. So we have to only mark the remaining nine electron pairs as lone pairs on the sketch.

Also remember that tellurium is a period 5 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 atoms are oxygens.

So for each oxygen, there are three lone pairs, and for tellurium, there is zero lone pair because all nine electron pairs are over.

Mark the lone pairs on the sketch as follows:

TeO3 Lewis Structure (Step 2)
Lone pairs marked on TeO3 Lewis structure | Image: Learnool

Formal charge

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

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

For tellurium atom, formal charge = 6 – 0 – ½ (6) = +3

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

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

TeO3 Lewis Structure (Step 3)
Formal charges marked on TeO3 Lewis structure | Image: Learnool

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

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

TeO3 Lewis Structure (Step 4)
Lone pair of left oxygen is converted, but still there are charges | Image: Learnool

Since there are charges on tellurium and oxygen atoms, again convert a lone pair of the oxygen atom to make a new Te — O bond with the tellurium atom as follows:

TeO3 Lewis Structure (Step 5)
Lone pair of right oxygen is converted, but still there are charges | Image: Learnool

There are still charges on tellurium and oxygen atoms, so again convert a lone pair of the oxygen atom to make a new Te — O bond with the tellurium atom as follows:

TeO3 Lewis Structure (Step 6)
Lone pair of top oxygen is converted, and got the stable Lewis structure of TeO3 | Image: Learnool

Final structure

The final structure of TeO3 has a central tellurium atom linked to three oxygen atoms through double covalent bonds. In this arrangement, the tellurium atom utilizes an expanded octet to accommodate twelve valence electrons across three double bonds, while each oxygen atom satisfies the octet rule by retaining two lone pairs. This specific configuration is preferred because it results in formal charges of zero for all atoms involved, representing the most energetically favorable distribution for the molecule. Consequently, this electronic pattern serves as the definitive and most accurate Lewis representation for tellurium trioxide.

Next: TeO2 Lewis structure

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Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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