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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Please help improve this article by adding citations to reliable sources. They are used together to make dyes.


This page was last edited on 30 Marchat This change in structure affects a chromophore in the pH indicator molecule. Auxochromes are a bunch of atoms that when combined auxochromds an appropriate chromophore heighten or enhance the color.

A molecule exhibits colour because it absorbs colours only of certain frequencies and reflects or transmits others. For example, phenolphthalein is a pH indicator whose structure changes as pH changes as shown in the following table:. Chromophores also alter the energy in the delocalized systems.

Color space Color model additive subtractive Chrimophores mixing Primary color Secondary color Tertiary color intermediate Quaternary color Quinary color Aggressive color warm Receding color cool Pastel colors Color gradient. 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. Electrolytic dissociation of the auxochrome group helps in binding and it is chromopyores to this reason a basic substance takes an acidic dye.


A—F List of colors: Chromophores are constituents of molecules that absorb auxochromrs reflect certain colors when light fall on them.

Auxochrome is a group of atoms which is functional and has the capability to alter the capacity of the chromophore to reflect colors. This phenomenon, known as resonancemeans that the molecule can absorb radiation of a particular frequency which is same as the frequency of electron movement within the molecule. Auxochromes are classified as either auxochtomes charged or negatively charged. Different auxochromes produce different effects in the chromophore which in turn causes absorption of light from other parts of the spectrum.

Similar behavior is seen in azobenzene which has a red color, but p -hydroxyazobenzene is dark red in color. A feature of these auxochromes is the presence of at least one lone pair of electrons which can be viewed as extending the conjugated system by resonance.

An auxochrome is known as a compound that produces a bathochromic anvalso known as red shift because it increases the wavelength of absorption, therefore moving closer to infrared light. From Wikipedia, the free encyclopedia.

Chromophore – Wikipedia

These are responsible for the absorption of different radiations with different wavelengths based on the energy of the electron.

Various factors in a chromophore’s structure go into determining at what wavelength region in a spectrum the chromophore will absorb. Chromophores with double covalent bond appear to be colored as a result of the heightened state of the electrons. Some of these are metal complex chromophores, which contain a metal in a coordination complex with ligands.


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. Halochromism occurs when a substance changes color as the pH changes. Unsourced material may be challenged and removed.

Auxochrome – Wikipedia

The presence of an auxochrome in the chromogen molecule is essential to auxxochromes a dye. A chromophore is the part of a molecule responsible for its color. 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. Academic Press, New York.

Chromophores are represented as nitrogen, carbon, oxygen and sulphur which usually have single or double bonds. The electrons which were in the resting state are elevated into the excited state because of the energy incorporated into it.

In biological molecules that audochromes to capture or detect light energy, the chromophore is the moiety that causes a conformational change of the molecule when hit by light. Linguistic relativity and the color naming debate Blue—green distinction in language Color history Color in Chinese culture Traditional colors of Japan Human skin color.