Phthalocyanine Green G
Phthalocyanine Green G, also called phthalo green, Viridian Hue, Pigment Green 7, Copper Phthalocyanine Green, C.I. Pigment Green 7, 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 numbers are 1328-45-6 and 1328-53-6 depending on the extent of chlorine substitition: 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.
Properties, chemistry and production
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.