Enter the difference in electronegativity and distance between atoms into the calculator to determine the molecular polarity. This calculator can also evaluate any of the variables given the others are known.

Molecular Polarity Formula

The following formula is used to calculate the molecular polarity.

MP = ∑ (ΔEN * d)

Variables:

  • MP is the molecular polarity (D) ΔEN is the difference in electronegativity between two atoms d is the distance between the two atoms (m)

To calculate the molecular polarity, multiply the difference in electronegativity between two atoms by the distance between them. Sum up these products for all pairs of bonded atoms in the molecule. The result is the molecular polarity.

What is a Molecular Polarity?

Molecular polarity refers to the distribution of electric charges in a molecule, which determines how a molecule interacts with other substances. It arises due to the difference in electronegativity between atoms in a molecule, where one atom might pull electrons more strongly than another, creating a dipole moment. This results in one part of the molecule having a slightly negative charge and another part having a slightly positive charge. The polarity of a molecule influences its physical properties such as boiling and melting points, solubility, and reactivity.

How to Calculate Molecular Polarity?

The following steps outline how to calculate the Molecular Polarity (MP) using the formula MP = ∑ (ΔEN * d).


  1. First, determine the difference in electronegativity (ΔEN) between the two atoms.
  2. Next, determine the distance (d) between the two atoms.
  3. Multiply the ΔEN by d.
  4. Repeat steps 1-3 for each pair of atoms in the molecule.
  5. Sum up all the values obtained in step 3 to get the total molecular polarity (MP).

Example Problem:

Use the following variables as an example problem to test your knowledge:

ΔEN (difference in electronegativity) = 0.5

d (distance between the two atoms) = 0.2 m