Comparison of Infrared and Raman Selection Rules

We have now discovered that the selection rules for Raman and IR spectra are different. The IR selection rule requires a vibration to belong to the same irreducible representation as X, y, z, whereas vibrations are Raman active if they belong to irreducible representations for the products of axes. This means that vibrations that show up in IR spectra need not be present in Raman and vice versa. 

This is not the case for molecules that belong to other point groups. For example, the cis isomer of 1,2-dichloroethene belongs to the C2V point group. Here, the character table 

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