Lewis structure of H3O+

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The Lewis structure of H₃O⁺ contains three single bonds, with oxygen in the center, and three hydrogens on either side. There is one lone pair on the oxygen atom, and the hydrogen atom does not have any lone pair.

Plus, there is a positive (+1) charge on the oxygen atom.

Steps

By using the following steps, you can easily draw the Lewis structure of H₃O⁺.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… hydrogen is a group 1 element and oxygen is a group 16 element. Hence, hydrogen has one valence electron and oxygen has six valence electrons.

Now H₃O⁺ has three hydrogen atoms and one oxygen atom.

So the total number of valence electrons = (valence electrons of hydrogen atom × 3) + valence electrons of oxygen atom

And H₃O⁺ has a positive (+1) charge, so we have to subtract one electron.

Therefore, the total number of valence electrons = 3 + 6 – 1 = 8

• Now decide the central atom

We can not assume hydrogen as 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.

Hence, assume that oxygen is the central atom.

So now, put oxygen in the center and hydrogens on either side. And draw the rough skeleton structure for the Lewis structure of H₃O⁺ something like this:

Also read: How to draw Lewis structure of AsH₃ (4 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since oxygen is surrounded by three hydrogens, use six electrons to show three chemical bonds as follows:

Also read: How to draw Lewis structure of Br₃^– (4 steps)

#3 Mark lone pairs

As calculated earlier, we have a total of 8 valence electrons. And in the above structure, we have already used six valence electrons. Hence, two valence electrons are remaining.

And two valence electrons represent one lone pair.

Note that oxygen is a period 2 element, so it can not keep more than 8 electrons in its last shell. And hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are hydrogens. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.

So the central atom (oxygen) will get one lone pair.

Now draw the Lewis structure of H₃O⁺ something like this:

In the above structure, you can see that the octet is completed on the central atom (oxygen), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of SeF₆ (4 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

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

Collect the data from the above structure and then, write it down below as follows:

• For each hydrogen atom

Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2

Formal charge = 1 – 0 – ½ (2) = 0

• For oxygen atom

Valence electrons = 6
Nonbonding electrons = 2
Bonding electrons = 6

Formal charge = 6 – 2 – ½ (6) = +1

Mention the formal charges of atoms on the structure. So the Lewis structure of H₃O⁺ looks something like this:

In the above structure, you can see that the formal charges of atoms are closer to zero. Therefore, this is the most stable Lewis structure of H₃O⁺.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

Now H₃O⁺ is an ion having a positive (+1) charge, so draw brackets around the above Lewis structure and mention that charge on the top right corner. And then, the Lewis structure of H₃O⁺ looks something like this:

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Related

• Lewis structure of AsH₃
• Lewis structure of Br₃^–
• Lewis structure of SeF₆
• Lewis structure of Br₂
• Lewis structure of H₂Se

External links

• Drawing the Lewis Structure for H3O+ – The University of Maryland
• Hydronium (H3O+) Ion Lewis Structure – Chemistry School
• H3O+ Lewis Structure, Geometry, Hybridization, and MO Diagram – Techiescientist
• H3O+ lewis structure, molecular geometry, bond angle, hybridization – Topblogtenz
• H3O+ Lewis Structure in 6 Steps (With Images) – Pediabay
• Draw the Lewis structure for H₃O⁺ and state its molecular geometry. Is it polar or nonpolar? – Homework.Study.com
• H3O+ Lewis Structure (Hydronium Ion) – Pinterest
• Lewis Dot of Hydronium H3O+ – Kent’s Chemistry
• Draw the Lewis structure for H3O+. What is the hybridization on the O atom? – Chegg
• Chemical Bonding: H3O+ Lewis Structure – The Geoexchange
• What is the structure of H3O? – Quora
• Draw a Lewis structure for H3O+ . Include all hydrogen atoms and show all unshared electrons and the formal charges, if any – Brainly
• H3O+ – CHEMISTRY COMMUNITY – Laurence Lavelle
• H3O+ Geometry and Hybridization – Chemistry Steps