Enter the vectors and their magnitudes into the calculator to determine the bond angle.

Bond Angle Formula

The following formula is used to calculate the bond angle in a molecule.

BA = cos^{(-1)} [(l1•l2) / (|l1|*|l2|)]


  • BA is the bond angle l1 and l2 are the vectors representing the two bonds • represents the dot product of the two vectors |l1| and |l2| are the magnitudes of the vectors l1 and l2 respectively

To calculate the bond angle, first calculate the dot product of the two bond vectors. Then, calculate the magnitudes of the two bond vectors. Divide the dot product by the product of the magnitudes. Finally, take the inverse cosine of the result to get the bond angle in degrees.

What is a Bond Angle?

A bond angle is the geometric angle between two adjacent bonds in a molecule. It is determined by the specific shape and structure of the molecule, which is influenced by the arrangement of electrons around the central atom. Bond angles can greatly influence the polarity and reactivity of a molecule. For example, in a water molecule (H2O), the bond angle between the two hydrogen atoms is approximately 104.5 degrees.

How to Calculate Bond Angle?

The following steps outline how to calculate the Bond Angle using the given formula:

  1. First, determine the dot product of the two vectors (l1•l2).
  2. Next, determine the magnitudes of the vectors (|l1| and |l2|).
  3. Next, calculate the product of the magnitudes (|l1|*|l2|).
  4. Finally, use the formula ? = cos^(-1) [(l1•l2) / (|l1|*|l2|)] to calculate the bond angle.
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem:

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

l1 = 3

l2 = 5

? = ?