Phosphorus trifluoride shows up as a colorless gas and it is highly toxic in nature similar to carbon monoxide or equivalent to phosgene. The is odorless, nucleophile, and weak base in nature and has a chemical formula that PF3.

You are watching: Pf3 electron pair geometry and molecular geometry

In this article, we will comment on Phosphorous trifluoride (PF3) lewis dot structure, molecule geometry, electron geometry, hybridization, polar or nonpolar, its link angle, etc.

“Phosphorus trifluoride is similar to carbon monoxide in the it is a gas i beg your pardon strongly binds to iron in hemoglobin, preventing the blood from absorbing oxygen.”

Properties the Phosphorous trifluoride

It has a molar fixed of 87.96 g/mol.It has a boiling allude of −101.8 °C and also a melting allude of −151.5 °C.It has actually a dipole minute of 1.03 D.It is non-flammable gas.It is a highly toxic gas and reacts progressively with water
Name that MoleculePhosphorous trifluoride
Chemical formulaPF3
Molecular geometry/shape that PF3Trigonal pyramid
Electron geometry the PF3Tetrahedral
Bond angle96°
Total Valence electron for PF326
The formal fee of PF30

Page Contents present
1 exactly how to attract lewis structure of PF3
2 straightforward steps for drawing the Lewis dot framework for PF3
3 What room the electron and also molecular geometry the PF3?
4 Hybridization the PF3
5 The bond angle of PF3
6 Phosphorous trifluoride polarity: is PF3 polar or nonpolar
7 Three determinants that show the polarity of PF3
9 summary

How to draw lewis structure of PF3

PF3 lewis structure is consisted of of one phosphorous atom that situated at the central position and also three fluorine atom the spread roughly the central atom. There space a full of 10 lone pairs(including main and terminal atoms) and three external inspection pairs existing in the lewis dot structure of PF3.

Let’s see exactly how to attract the lewis structure of PF3 by complying with some straightforward steps-

Simple steps for drawing the Lewis dot structure for PF3

1. Count total valence electron in PF3

In the first step, we have actually to discover how many valence electrons space there in PF3, so that we deserve to distribute them around main and terminal atoms with the goal of completing your octet shell.

You have two methods to find out the valence electron for a particular atom, one of two people by spring at your periodic team or by creating their electronic configuration. We will use the technique of the periodic team for finding the valence electron in PF3.

Phosphorous atom belongs to Group 5A or 15A in the routine table, hence, it has actually a 5 valence electron in that outermost shell whereas fluorine atom belongs come Group 7A or 17A, hence, it has a 7 valence electron in that is outermost shell.

⇒ total valence electron in Phosphorous = 5

⇒ complete valence electron in Fluorine = 7

∴ full valence electron easily accessible for drawing the PF3 lewis framework = 5 + 7*3 = 26 valence electrons  <∴PF3 has three fluorine atom and one phosphorous>


2. Uncover the the very least electronegative atom and also placed it at center

Which is an ext electronegative, phosphorous or fluorine atom? the course, the fluorine atom(3.98) is more electronegative 보다 phosphorous(2.19). Hence, the fluorine atom goes external in the lewis diagram conversely, the phosphorus atom fetched the chair of the main position.


3. Affix phosphorous and fluorine with a single bond

In this step, we start illustration the PF3 skeletal framework by bonding together Phosphorous and Fluorine v a single bond.


Now look in ~ this structure and count how plenty of electrons we used till now and how countless are left. 

As three single bonds are used in the above structure that contains 6 electrons and also we have a full of 26 valence electrons are easily accessible for illustration the PF3 lewis structure.

∴ (26 – 6) = 20 valence electrons

So, we room left v 20 valence electrons.

4. Inserted remaining valence electrons beginning from external atom first

In this step, we have to place the remaining valence electrons beginning from the much more electronegative atom or native the outer atoms.

So, fluorine is more electronegative 보다 phosphorous and also it needs 8 electrons to complete its octet rule.

Fluorine atoms already sharing 2 electrons through the aid of a solitary bond so it only demands 6 more electrons to finish its octet rule.


As you see in the over structure, each fluorine has actually 6 electrons stood for as dots and 2 electrons in form of a solitary bond, hence, the fluorine atom has a full of 8 electrons and it completed its octet comfortably.

Now find how countless valence electrons room left.

Three fluorine atom in the above structure supplied 18 electrons(represented together dots) native a complete of 20 continuing to be valence electrons.

∴ (20 – 18) = 2 valence electrons

So, us left with just 2 electrons.

5. Complete main atom octet and use covalent shortcut if necessary

We room left with just 2 valence electrons and also by looking at the 4th step structure, we see, the main atom phosphorus has only 6 electrons(three single bonds), hence, it demands 2 an ext electrons to finish the octet and attains stability.

So, placed the staying two electron on the phosphorous atom and also complete that is octet.


Lewis dot structure for PF3

As you watch in this PF3 lewis period structure, phosphorous and also fluorine completed your octet, and also everything looks fine, but, because that the benefits of satisfaction, we should also determine the formal charge in the over structure to recognize whether the is secure or not.

6. Check the security with the aid of a formal fee concept

To calculate the formal fee in the PF3 lewis structure. Use the formula provided below-


Let’s begin with the main atom which is phosphorous in the PF3 molecule.

For phosphorous atom:

⇒ Valence electron of phosphorous = 5

⇒ Lone pair electron on phosphorous = 2

⇒ Bonding electrons of phosphorous(3 solitary bonds) = 6

∴ (5 – 2 – 6/2) = 0 formal charge on the phosphorous central atom.

Each fluorine atom in the PF3 lewis structure has the same variety of lone pair and bonded pair electrons, hence, simply count formal charge for just one fluorine atom

 For fluorine atom

⇒ Valence electrons of fluorine = 7

⇒ Lone pair electrons on fluorine = 6

⇒ Bonding electrons about fluorine (1 solitary bond) = 2

∴ (7 – 6 – 2/2) = o formal charge on each fluorine atom.

Hence, every atom in PF3 gets a formal charge equal to zero.


Therefore, the over lewis structure of PF3 (phosphorous trifluoride) is the many stable and reliable

The molecular geometry the PF3 is a trigonal pyramid and its electron geometry is tetrahedral due to the fact that phosphorous has actually Sp³ hybridization through 5 valence electrons in that valence shell and it makes three shortcut pairs, one v each fluorine atom.

And one lone pair is existing on the main phosphorous atom that tries come repel the bonded bag of electrons, together a result, the adjacent atoms push apart providing its geometry trigonal pyramid.


As you watch in the above structure, the lone pair top top the phosphorus atom defeat the nearby electron pairs, together a result, the 2 fluorine atom in equatorial position pushes much apart offering the molecule geometry the PF3 very same as a trigonal pyramid.

Let’s see exactly how to discover the molecular and electron geometry that PF3 making use of the VSEPR chart and AXN notation.

AXN technique is a famous method of determining the molecular and electron geometry utilizing the VSEPR chart.


AXN notation because that PF3 molecule:

A denotes the central atom, so, in the PF3 molecule, phosphorous is the central atom. A = PhosphorousX denotes the bonded atoms to the main atom, together we know, phosphorous is bonded with 3 fluorine atoms. Therefore, X = 3N denotes the lone pair top top the central atom, as per PF3 lewis structure, phosphorous has actually only one lone pair. Hence, N = 1

So, the AXN notation for the PF3 molecule i do not care AX3N1

As per the VSEPR chart, if a molecule main atom is attached with 3 bonded atoms and has contained only one lone pair top top the main atom climate the molecular geometry of the molecule is the trigonal pyramid in nature, and also electron geometry is tetrahedral.


Hence, the molecular shape for PF3 is a trigonal pyramid and also its electron geometry is tetrahedral.


PF3 molecule geometry/shape

Hybridization the PF3

Let’s uncover the hybridization of PF3 through the steric variety of its main atom.

“Steric number is the enhancement of a total variety of bonded atoms about a central atom and the lone pair current on it.”

∴ Steric number of PF3 = (Number the bonded atoms attached to phosphorous + Lone pair top top phosphorous)

As per the lewis structure of PF3, the main phosphorous atom is external inspection with three fluorine atoms and also it consists of one lone pair also.

∴ Steric number of PF3 = (3 + 1) = 4

Steric numberHybridization

So, for a steric number of four, we get the Sp3 hybridization ~ above a phosphorous atom in the PF3 molecule.

The newly developed hybrid orbitals in PF3 molecule have 25% actions of the s orbital and also 75% behavior of the ns orbital.

The bond edge of PF3

“Phosphorus trifluoride has actually an F−P−F bond edge of approximately 96°“.


PF3 is a polar molecule due to the fact that of that is asymmetric shape and electronegativity difference between phosphorous and fluorine which reason non-zero dipole moment.

For knowing, is PF3 polar or non-polar? we will talk about three determinants 1. electronegativity 2. dipole moment 3. Geometrical or molecule shape.

Three factors that suggest the polarity the PF3 

1. Electronegativity: 

The difference between the electronegativity that Phosphorous and also fluorine is directly proportional come the Polarity that the PF3 molecule.

The electronegativity of the fluorine atom is 3.98 and for the phosphorous atom, its worth is 2.19.

So, being an ext electronegativity that fluorine aid it come attract much more bonded electron than phosphorous. Therefore, fluorine profit a partial an adverse charge, and also phosphorous profit a partial optimistic charge.

Positive and an adverse charges cause non-uniform fee distribution around the PF3 structure. Hence, it likewise causes PF3 to end up being polar in nature.

Also, the electronegativity difference of fluorine and also phosphorous atom is better than 0.5 which ensures the PF3 is extremely polar in nature according to the Pauling scale.

2. Dipole moment

The net dipole minute of the PF3 molecule is 1.03 D. Dipole moment measure the strength of polarity. 

The larger the electronegativity distinctions of atoms better is the polarity and dipole moment.

The dipole that the PF3 molecule originates in the downward and also upward direction since of the lone pair present in Phosphorous. Hence, it reasons a non-zero dipole minute which causes the polar nature that PF3.

⇒ Dipole minute formula = fee on the atom * the distance between them 

∴ D = Q × R

3. Geometrical or molecular shape

The geometrical shape is likewise a large factor to identify is PF3 polar or non-polar.

As we understand molecular geometry that PF3 is trigonal pyramidal which is asymmetric and also when the shape of the molecule is asymmetric or distorted it no cancel the dipole moment throughout the molecule. Hence, reason polar nature the the molecule

All these factors are sufficient to understand why PF3 is polar in nature.


Why bond angle in PF3 greater than PH3?

This is because, in the PF3 molecule, back bonding occurs.

“The exchange of electrons in between an atomic orbital on one atom and an antibonding orbital on one more atom is well-known as back bonding.”

Due to ago bonding, greater bond pair-bond pair repulsion exists in PF3 보다 PH3.

Hence, the greater the repulsion in between bonded pairs, the larger is the shortcut angle.

Also, in the PF3 molecule, fluorine is a highly electronegative atom and also it fetched much more electrons in the direction of itself which likewise creates more repulsion, and also this causes, widening the bond edge in PF3. 

The almost right bond angle of PH3 is 93° and also for PF3, it is 96°.

How many lone pairs and also bond pairs are present approximately Phosphorous in the PF3 lewis structure?

According to the lewis dot structure of PF3, Phosphorous has 1 lone pair and 3 bonded pair i beg your pardon is fastened with 3 fluorine atoms.

How go the PF3 lewis dot structure obey the octet rule?

If an atom gets an ext or much less than 8 electron in an outermost covering then we have the right to say the atom violates the octet.

Phosphorous atom has five valence electrons in that is outermost shell and also it is capable of forming three covalent bonds v the surrounding atom to complete its octet.

Whereas the fluorine atom has actually 7 valence electrons and also is capable of creating only one covalent bond with various other atoms.

Therefore, in the PF3 lewis structure, phosphorous together a main atom creates three covalent bond (one with each fluorine atom) and also fulfills the octet necessity whereas the fluorine atom additionally completes its octet by one covalent shortcut attached with the central atom.

∴ all atoms in the PF3 lewis dot framework get exactly 8 electrons in their octet, hence, they are obeying the octet rule

Why is the molecular geometry the PF3 is trigonal pyramid conversely, its electron geometry is tetrahedral?

This is because there is a slight difference in molecular and electron geometry. Molecule geometry takes just bonded atoms right into account if calculating the form of any type of molecule.

Whereas the electron geometry considers both bonded atoms and also lone bag while predicting the geometry of any type of molecule.

The phosphorous central has 4 areas of electron density(one lone pair + 3 external inspection pairs) hence, as per VSEPR theory, the electron geometry of PF3 is distorted tetrahedral.

Whereas the molecule geometry of PF3 is trigonal pyramidal that has one atom in ~ the center and three atoms at the trigonal base corners and it is comparable to a tetrahedron however it walk not take into consideration lone pair.

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The total valence electron accessible for drawing the PF3 lewis framework is 26.The steric variety of the main atoms in phosphorous trifluoride is 4 the ensures that it has actually an Sp3 hybridization.PF3 is polar in nature as result of its distorted shape that reasons uneven charge distribution all end the atom leader to a non-zero dipole moment and also makes it polar in nature.The molecular geometry or form for PF3 is the trigonal pyramid.The electron geometry because that PF3 is tetrahedral together it main has 4 areas of electron density.Lewis dot framework of PF3 contains 1 lone pair top top the main atom(phosphorous) and also 3 lone pairs on each external atom(fluorine).