WEB TUTORIAL - Group Theory

Point Group Character Tables

• N Values (all 1 in this case) are the numbers preceding the symmetry element and are important for use in the Reduction Formula.

• The listed Symmetry Elements are all of the elements present in the point group.
A good way to check you have assigned the correct point group is to check the character table off against your molecule and make sure all of the elements in your molecule are present in the character table and vice versa.
• The h Term is a summation of all of the N Values and varies for each character table.
• _I Values are the entries into the table, which are used in the Reduction Formula.
• Normal/Quadratic Terms refer to mathematical properties in the table. However If there is a linear entry, the vibration accosiated with that row (A₁, B₁ etc.) will be IR active. If there is a quadratic term it is Raman active.
• Row Names are the labels given to each mode of vibration of the molecule.
A page with all of the Character Tables can be found here.