Is PH3 Polar or Nonpolar

PH3 polarity

Are you wondering is PH3 polar or nonpolar? This article will help you clarify all your confusion. Before proceeding to PH3 polarity, let’s understand what PH3 is.

The phosphine (PH3) is a flammable, colorless, and very toxic gas that smells like rotten fish. It is flammable in the air due to substituted and diphosphate (P2H4) and phosphine (PH3).

When white phosphorus reacts with sodium, phosphine is made from this process—the concentration of phosphine is found in the earth’s atmosphere at high and low variable concentrations.

The phosphine (PH3) was first obtained in 1783 by heating white phosphorus in a solution of potassium carbonate.

It is also found in Jupiter’s turbulent atmosphere, where it forms inside the planet’s high temperature and reacts with other compounds in the upper atmosphere.


The chemical formula of phosphine is PH3.

Reaction Of White Phosphorus With Sodium:

3 KOH + P4 + 3 H2O → 3 KH2PO2 + PH3

Is PH3 Polar or Nonpolar

PH3 polar or nonpolar
Polarity of PH3

Explanation 1:

Phosphine (PH3) is a polar molecule because PH3 has lone electrons and has electron-electron repulsion, resulting in a bent structure. The bond P-H is nonpolar because its electronegativity is the same, but phosphorus has lone pair, making the whole molecule polar. Therefore, PH3 is a polar molecule.

Explanation 2:

Phosphine (PH3) is a polar molecule because phosphorus has five valence electrons and three hydrogen atoms, which gives three electrons to atom p to complete the octet. Therefore in phosphorus (P), there must be an unshared pair of electrons, which form a negative region. The hydrogen charge will be positive, which results in a PH3 molecule with a positive and negative region; therefore, PH3 is considered a polar molecule.

NH3 is also a polar molecule for the same reason.

Explanation 3:

The PH3 is a polar molecule because there is uneven charge distribution throughout the molecule, which results in a dipole moment and making PH3 a polar molecule. The lone pairs on the atom phosphorus (P) gives a strong dipole moment.

Explanation 4:

The PH3 is a polar molecule because, in PH3, the atom has one lone pair of the electron, making the molecule polar. Still, the electronegativity of P-H is nonpolar because the electronegativity of both is mostly the same.


Simple is that PH3 is a polar molecule.

PH3 Molecular Geometry

phosphine (PH3) molecular geometry
phosphine (PH3) shape

The molecular geometry of PH3 is trigonal pyramidal, and the fourth corner of it is created for the phosphor free electron pair.

In PH3, the phosphorus has 5 valence electrons and 3 hydrogen atoms, so if we add it and divide it by two, it becomes four, which stands for sp3 hybridization.

The shape of the sp3 hybridization with no lone pair is tetrahedral, and the shape of the sp3 hybridization with one lone pair is pyramidal. Ph3 has one lone pair. Therefore, its molecular geometry is trigonal pyramidal.


Simple is that the molecular geometry of PH3 is trigonal pyramidal.

PH3 Lewis Structure

Lewis structure of ph3
Ph3 Lewis structure

To draw the PH3 Lewis structure, follow the below instructions.

  • First of all, find out the total number of valence electrons in the NH3 using the periodic table.
  • In PH3, phosphorus (P) is in group 5 in the periodic table and has five valence electrons. Hydrogen is in group 1 and has one valence electrons, but we have three hydrogens; therefore, we will multiply 1(3)=3
  • To find the total number of valence electrons in the PH3, we will add phosphorus (P) and hydrogen (H) valence electrons, which become 5+3= 8.
  • Now we know that we have a total of eight valence electrons in the PH3.
  • Put the phosphorus (p) in the center and add hydrogen around it. Remember, hydrogen always goes on the outside.
  • To form a chemical bond between each atom, put the electrons between hydrogen and phosphorus.
  • Now you have used six valence electrons, and you need to use the eight to complete the octet. Put the last two in the center for a total of eight valence electrons.
  • The phosphorus (p) in the center has eight valence electrons, and its shell is full. 
  • Hydrogen only needs two valence electrons to the full outer shell.

If you didn’t understand the above steps watch this video to draw the Lewis structure of PH3.

Hybridization Of PH3

The hybridization of PH3 has not been defined because of Arago’s rule. According to Drago’s rule, if the central atom’s electronegativity is comparable with that of hydrogen, it doesn’t take the part of hybridization.

The bond angle between P-H is 90 degrees suggesting the pure shape of the P atom. You can also determine the hybridization from the geometry of the compound.

The hybridization type of PH3 is Nil.


The PH3 hybridization is Nil.

Is PH3 Ionic Or Covalent

The PH3 is a polar covalent compound, but phosphorus’s electronegativity and hydrogen are mostly the same, with a nonpolar covalent bond. The whole PH3 molecule is polar.

The phosphorus (P) has one lone pair of electrons, and it is bonded to the three hydrogen atoms.

You can’t say 100% about the bond that it’s ionic or covalent. Still, it’s large when you see the electronegativity difference, so the ionic character chances increase. When the electronegativity is nearly the same, then there is an increase in the covalent character.


Simple is that the PH3 is covalent because of its electronegativity difference.

PH3 Dipole Moment

The PH3 dipole moment is 0.58D. It is non-symmetrical, and its dipole moment is high than PCL3.

The arrangement of both PCL3 and PH3 is pyramidal and have one lone pair of electron. The PH3 has a greater dipole moment because In PH3, the dipole moment is from hydrogen to phosphorus, and the dipole moment of the liquid is in the same direction as the dipole of the lone pair.

For PCl3, the dipole moment points to the chlorine atom. The resulting dipole moment is opposite to the direction of a single pair of dipoles, and its effective moment is reduced. Therefore, the dipole moment is smaller than PH3.


Simple is that the dipole moment of PH3 is 0.58D.

PH3 Electron Geometry

The electronic and molecular geometry of PH3 is pyramidal, In PH3, the phosphorus atom has 5, and the hydrogen atom has 1 valence electron. In the phosphorus, due to the one lone pair of electrons, the structure becomes pyramidal.


Ph3 molecular and electronic geometry is pyramidal.

Properties Of  Phosphine (PH3)

  • The molar mass of PH3 is 33.99758 g/mol.
  • The appearance of PH3 gas is colorless and has fish or garlic-like odor.
  • Its density is 1.379 g/l, gas (25 °C).
  • It is soluble in alcohol, benzene, and ethanol.
  • The boiling point of PH3 is −87.7 °C (−125.9 °F; 185.5 K), and the melting point is −132.8 °C (−207.0 °F; 140.3 K).


Above are the properties of PH3.

Uses Of Phosphine (PH3)

  • In the semiconductor industry, phosphine is used to introduce phosphorus into silicon crystals.
  • It is also used as a fumigant and polymerization initiator.
  • It is used in food products and tobacco.
  • It’s also used Used to prepare various flame retardants.
  • Ph3 is used in chemical processing as well.


Above are the uses of PH3.

Final Thoughts

That was all about is PH3 polar or nonpolar. I hope it’s now clear to you that PH3 is a polar molecule because of the nearly same electronegativity of both phosphorus (P) and hydrogen (H) atoms.

If you want to know in detail why PH3 is polar, then read the above four explanations that will clarify all your confusion.

The PH3 molecular and electronic geometry is trigonal pyramidal. Many people are confused about drawing the Lewis structure of PH3, but it’s very simple to watch the above video to make everything easy for you.

The hybridization of PH3 is Nil, which means it is not defined. The PH3 is a covalent bond because it’s mostly the same electronegativity.

The phosphine dipole moment is 0.58 D. The PH5 does not exist, but PF5 does.

Do you think we have missed something about the PH3 topic? Let us know in the comments section below we will add them.

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