Hydrogen Phosphate, H3PO4 is an important chemical compound. Phosphoric acid, likewise known as orthophosphoric acid is a colorless and also odorless weak acid v an 85% aqueous solution. The is also accessible in a transparent solid-state with a thickness of 1.834 g/cc.

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Phosphoric acid has a most uses in everyday life. It has actually its applications in dentistry during fillings and also roughening of teeth surfaces. Various other than this, it has actually a wide variety of applications in the people of fertilizers.

It is likewise used in anti-rust treatment, microfabrication, sanitizers, and also compound semiconductor industry.Health hazards encompass severe skin irritation and also damages to the eyes.

H3PO4 Lewis Structure

To discover the nature of bonding inside any type of chemical molecule, the very first and foremost step is to have a basic idea about its structure.

Lewis structure diagram provides us a simple representation of any given molecular composition v the aid of electron period methodology.


The over diagram reflects the Lewis structure of a common molecule NO or nitric oxide.

Here, together we deserve to see, we have obtained a 2D diagrammatic map out that can help us understand the electronic arrangement in one undetailed yet crisp manner.

We have used period notations to stand for the valence electrons and lone pairs surrounding the ingredient atoms. We have used atomic symbols and also straight lines to suggest the type of bond formed.

Let us see just how we can uncover out the most perfect Lewis Structure lay out for H3PO4:

Steps to draw Lewis framework for H3PO4

Step 1: Find the end the total valence electron number.

A single molecule that hydrogen phosphate has three atom of hydrogen, one phosphorus, and four oxygen atoms.

P belong to group 5 of the routine table, therefore has 5 valence electrons. O belongs to the chalcogen group or team 6, hence has 6 valence electrons.

A hydrogen atom has actually only one atomic number of 1, because of this the valency. Total variety of valence electron in H3PO4

= 1*3 + 5 + 6*4 = 32.

Step 2: identify the central atom.


The above-mentioned chart provides us the electronegativity worths of all main group elements in the regular table.

During the development of any kind of molecule, usually, the the very least electronegative aspect takes increase the main position prevent a couple of exceptions.

This is probably because of the fact that electropositive aspects are much more likely to be conducive to sharing electrons and also forming bonds help in preserving stability.

Here, we have actually P as the least electronegative element and it will become the central atom. Because we have a triatomic molecule, we have placed the atoms in the following manner:


Step 3: lay out the molecular structure with electron-dots.

We have now surrounding the molecule atoms with the help of dot notations.


Step 4: check Octet Rule.

The main group aspects of the periodic table have actually a tendency to acquire octet construction in their outermost shells i.e. They tend to follow the valence covering configurations of the noble gases that the same period.

For E.g. Carbon tends to obtain the octet configuration of Neon (Atomic No:10).

So, let united state now check the valence shells approximately the atom in the Lewis Structure.

As we have the right to see quite vividly, all the atoms have attained octet fulfillment like P and also O every of the atoms having actually eight electrons.

However, hydrogen has actually only 2 electrons bordering it however it additionally has completed noble gas configuration( in this case, that is Helium, atomic No: 2 ).

Step 5: type of bond formation.

As octet fulfillment has been done, let us examine the type of bond formation inside a molecule that hydrogen phosphate.

Since two electrons have actually been shared between each of the atomic pairs, we will certainly stick to solitary bonding.

Step 6: check Formal Charge.

We can not verify whether we have acquired the most suitable Lewis framework configuration unless and until we have actually checked the formal charge values.

A charge is assigned come a bonded atom assuming that it is common equally amongst all the bonded atoms within the offered molecule. This is known as the official charge.


Formal charge of ns = 5 – 0.5*8 – 0 = +1.

Formal charge of O at the optimal = 6 – 0.5*2 – 6 = -1.

Formal fee of other O atoms each = 6 – 0.5*4 – 4 = 0.

Formal charge of each H atom = 1 – 0.5*2 – 0 = 0.

Since P has a formal fee of +1, we can do part variations to do it the a lesser value.

An exception to Octet Rule

In the Lewis Structure, us will shift the optimal electrons from the O atom at the height towards the p atom to form double bonds.


This will certainly make P have actually a valence electron variety of 10 hence an exemption to the octet rule.

The formal fee of the O in ~ the top is currently 0. The formal charge of p = 0.

The most an ideal lewis framework for H3PO4 is:


H3PO4 molecule Geometry

Electrons are like-charged particles that type a negatively charged cloud neighboring the atom nuclei within a polyatomic molecule.

This causes repulsion which is necessary to be minimized for stability and also balance. This is known as the VSEPR concept or Valence shell Electron Repulsion Pair Theory.

Now, for H3PO4, we have to find out the number of electron density regions surrounding the main atom the the molecule.

Here, the central atom is Phosphorus.

If us look in ~ the Lewis structure, us can find out the there are 4 electron density regions approximately P: 3 OH and also one O region.

There is zero lone pair ~ above P.


So, follow to VSEPR theory, we gain a tetrahedral arrangement.



Orbital Hybridization: A quick Intro

An orbital have the right to be identified as the mathematical probability that the existence of electrons in any given local space.We have actually several atomic orbitals ( AOs ) of various shapes and energy levels choose s, p, d, f.

When AOs combine and fuse to form hybrid orbitals favor sp, sp2, sp3d, and so on, the procedure is recognized as orbit hybridization. This is an essential concept of chemical bonding.

H3PO4 Hybridization

Now, let united state look in ~ the molecule and understand the principle of sigma and also pi bonds. A single bond is composed of one sigma shortcut i.e. A sigma pair.

A dual bond however consists the one sigma and also one pi pair. The pi pair does not take part in the hybridization process.

Let united state look in ~ the sigmas in H3PO4.

The main atom ns is bonded singly with three O atom ( developing the O-H or hydroxyl bonds) and also doubly bonded through one O atom.

So, the three single bonds and one double bond consists of 4 sigmas.

The hybridization the the H3PO4 molecule is sp3.


What do you mean by Polarity?

During formal fee calculation, we assume the electrons space shared in between bonding atoms in equal proportions, yet this is no what wake up in fact in every cases.

If we take into consideration a molecule favor H2 or Cl2, since both the the molecules being comparable have the same electronegativity values, we deserve to say the the electron bag are mutual equally here.

But if we take into consideration HCl, because H and also Cl have various electronegativity values, there will be a existence of partial charges.

The atom having actually less electronegativity worth will have actually a partial hopeful charge ( δ+) and the much more electronegative atom will certainly possess a partial negative charge ( δ- ).

This is known as polarity. HCl is a polar molecule conversely, Cl2 and H2 room nonpolar.

Polarity that H3PO4

Let us look in ~ the Pauling Electronegativity chart:

Electronegativity value of P: 2.19

Electronegativity value of O: 3.44

Electronegativity worth of H: 2.20

H3PO4 is one asymmetrical tetrahedral molecule with distinctions in electronegativity values, hence, it is polar.The network dipole moment right here is no equal come zero.

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In this article, we learned a lot around the nature of chemical bonding emerging inside H3PO4. We have disputed the actions to attract the perfect Lewis Structure and the molecule geometry via VSEPR theory. Us have additionally talked around hybridization and also polarity.