Basic auxochromes. Auxochrome vs chromophore. Auxochrome is a Greek word arising from two word roots; ‘auxo’ meaning “to increase” and. This lesson explains the parts of a molecule responsible for color: chromophores and auxochromes. Chromophores and auxochromes are. CHROMOPHORE IS THE ACTUAL PART RESPONSIBLE FOR IMPARTING COLOR TO A MOLECULE; AUXOCHROME IS A HELPER THAT.

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Electrolytic dissociation of the auxochrome group helps in binding and it is due to this reason a basic substance takes an acidic dye. Linguistic relativity and the color naming debate Blue—green distinction in language Color history Color in Chinese culture Traditional colors of Japan Chromophoers skin color.

Chromophores are constituents of molecules that absorb or reflect certain colors when light fall on them. Color model additive subtractive Color mixing Primary color Secondary color Tertiary color intermediate Auxochrlmes color Quinary color Aggressive color warm Receding color cool Pastel colors Color gradient. This is a property of pH indicatorswhose molecular structure changes upon certain changes in the surrounding pH.

The chromophore is a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum. A—F List of colors: Chromophores do not absorb light without the requisite contents but with the presence of an auxochrome there is a shift in the absorption of these chromogens. Unsourced material may be challenged and removed.

An auxochrome is a functional group of atoms attached to the chromophore which modifies the ability of the chromophore to absorb light, altering cgromophores wavelength or intensity of the absorption.

Difference between auxochrome and chromophore

All substances like dyes produce colors by absorption of visible light owing to the various constituent compounds. Auxochrome is a group of atoms which is functional and has the capability to alter the capacity of the chromophore to reflect colors. The nature of the central metal can also auxoxhromes the absorption spectrum of the metal-macrocycle chromophorez or properties such as excited state lifetime. An auxochrome helps a dye to bind to the object that is to be colored.


Auxochromes are classified as either positively charged or negatively charged. The electromagnetic spectrum has a very wide variation in wavelengths but the human eye visualizes only short wavelength radiation.

However, if an auxochrome is present in the meta position to the chromophore, it does xnd affect the color. Chhromophores an auxochrome is present in the meta position of the chromophore, then there is no change in the color.

Retrieved from ” https: Different auxochromes produce different effects in the chromophore which in turn causes absorption of light from other parts of the spectrum. The chromophore is the part of the molecule where the energy difference between two different molecular orbitals falls within the range of the visible spectrum and hence absorbs some particular colours from visible light.

Views Read Edit Chromophkres history. An auxochrome is a functional group of atoms with one or more lone pairs of electrons when attached to a chromophore, alters both the wavelength and intensity of absorption. Because of their limited extent, the aromatic rings only absorb light in the ultraviolet region, and so the compound appears colorless in the pH range.

From Wikipedia, the free encyclopedia. If these groups are in direct conjugation with the pi -system of the chromophore, they may increase the wavelength at which the light chromkphores absorbed and as a result intensify the absorption.

Chromophores auxochroes represented as nitrogen, carbon, oxygen and sulphur which usually have single or double bonds. Chemical compounds Color Chemical reactions. Auxochrome increases the color of any organic substance. To convert basic dyes to acidic dyes, the negatively charged sulphonic groups are often used.


Auxochrome – Wikipedia

Various factors in a chromophore’s structure go into determining at what wavelength region in a spectrum the chromophore will absorb. Dyes containing auxochromes are basically aromatic compounds and include the presence of aryl rings which have delocalized electron systems. Academic Press, New York. If the energy incorporated is changed, automatically the wavelength of the radiation it absorbs will also change and the compound will appear colored. By using qnd site, you agree to the Terms of Use and Privacy Policy.

Visible light that hits the chromophore can thus be absorbed by exciting an electron from its ground state into an excited state. Auxochromes are molecules which are attached to non ionizing compounds yet retain their ability to ionize and chroophores the ability of absorbing light when attached to a chromophore.

Views Read Edit View history. These are responsible for the absorption of different radiations with different wavelengths based on the energy of the electron.

Normally, auxochromes which intensify the colour are chosen. Hence the molecule appears coloured. It increases the color of any organic compound. Please help improve this article auxochromess adding citations to reliable sources. This makes the three rings conjugate together to form an extended chromophore absorbing longer wavelength visible light to chromophoees a fuchsia color.

Light waves with frequency very close to their natural frequency are absorbed readily. Chromophores with double covalent bond appear to be colored as a result of the heightened chtomophores of the electrons. Azobenzene is an example of a dye which contains a chromophore.