Blue FCF or FD&C Blue # 1
2;Bis[4-(N-ethyl-N-3-sulfophenylmethyl)aminophenyl]-2-sulfophenylmethylium disodium salt
Blue FCF is Blue:
Molecules are made up of atoms linked together by sharing electrons. Electrons in atoms and molecules are restricted to energy levels. This is somewhat like stairs in that you can occupy the level of a stair but not any level in between.
When electrons are spread out over many atoms, the energy levels become closer together. The electrons in atoms and molecules can jump up energy levels if exactly the right amount of energy is supplied. This amount of energy can be provided by electromagnetic radiation.
Visible light is one form of electromagnetic radiation. Small molecules, with little spreading out of electrons, have large energy steps and so require electromagnetic radiation of higher energy than visible light. Consequently, visible light passes through such molecules and they appear transparent. For larger molecules, if the electrons are spread out enough in the molecule, the energy levels for the electrons are close enough together that visible light has enough energy to make the electrons jump up a level.
When this happens, the particular energy of light, which corresponds to a particular wavelength or color, is absorbed and disappears. The remaining light, lacking this color, shows the remaining mixture of colors as non-white light.
For molecules to spread electrons out enough to absorb visible light, several double bonds (=) must be present alternating with single bonds (-). You can note this phenomenon in the structural diagram above. The wavelength of light absorbed in the Brilliant Blue FCF corresponds to 630 nm.Page by Sandra Allen
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