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Phthalocyanine Green G

  Phthalocyanine Green G, also called phthalo green, Pigment Green 7, Copper Phthalocyanine Green, C.I. Pigment Green 42, Non-flocculating Green G, Polychloro copper phthalocyanine, or C.I. 74260, is a synthetic green pigment from the group of phthalocyanine dyes, a complex of copper(II) with chlorinated phthalocyanine. It is a very soft green powder insoluble in water. Its CAS number is [1328-45-6] and [1328-53-6]. Its chemical formula ranges from C32H3Cl13CuN8 to C32HCl15CuN8. It is a bright, high intensity colour used in oil and acrylic based artist's paints, and in other applications.

Phthalocyanine green is a phthalocyanine blue pigment where most of the hydrogen atoms are replaced with chlorine. The strongly electronegative chlorine atoms influence the distribution of the electrons in the phthalocyanine structure, shifting its absorption spectrum. It is made by chlorination of the phthalocyanine blue as a melt of sodium chloride and aluminium chloride, to which chlorine is introduced at elevated temperature. Material from some manufacturers may be contaminated by trace amounts of polychlorinated biphenyls.

The phthalo green molecules are highly stable. They are resistant to alkali, acids, solvents, heat, and ultraviolet radiation.

Due to its stability, phthalo green is used in inks, coatings, and many plastics. In application it is transparent. The pigment is insoluble and has no tendency to migrate in the material. It is a standard pigment used in printing ink and packaging industry. It is also allowed in all cosmetics except those used around the eyes, and is used in some tattoos.

Copper phthalocyanine green 36 is another variant where part of the chlorine atoms is replaced with bromine; the mixture of this with phthalocyanine green can reach a wide tonal range of greens to green-yellows.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Phthalocyanine_Green_G". A list of authors is available in Wikipedia.
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