Brief difference between auxochrome & chromophore.

The difference between chromophore and auxochrome is that a chromophore is a part of a molecule that absorbs visible light and reflects a certain color, while an auxochrome is a group of atoms that modifies the ability of the chromophore to absorb light and enhances its color.


A chromophore is usually a conjugated system of double bonds or aromatic rings that can undergo electronic transitions when exposed to light. For example, the nitro group (-NO2) is a chromophore that gives a yellow color to nitrobenzene. An auxochrome is a functional group that has one or more lone pairs of electrons that can extend the conjugation of the chromophore by resonance. For example, the amino group (-NH2) is an auxochrome that shifts the absorption of nitrobenzene from 225 nm to 280 nm and increases its intensity.

Some common examples of chromophores are ethylene, acetylene, carbonyl, nitrile, azo, and nitro groups. Some common examples of auxochromes are hydroxyl, amino, aldehyde, and methyl mercaptan groups. You can find more information about these terms and some examples in the following web search results: Define and differentiate between auxochromes and chromophores, What is the Difference Between Auxochrome and Chromophore, and Difference between auxochrome and chromophore. I hope this helps you understand the concept better. 😊

BY ALEENA SAEED

                                                Department of Chemistry