Pigment Yellow G583 – A Misclassified Pigment and its Relationship with other Acetoacetanilide Azo Pigments

Pigment Yellow G583 (nominally C.I. Pigment Yellow 6) has been compared with another version of C.I. Pigment Yellow 6 (Recolite Fast Yellow 3G) and the colour and X-ray powder diffraction pattern have been found to be different. Density measurements, crystal structure analysis and chemical analysis have shown that the former is a mixed crystal of 60mol% C.I. Pigment Yellow 6 and 40mol% C.I. Pigment Yellow 5. Pigment Yellow G583 was then compared crystallographically with a series of similar pigments, and it has been concluded that the structure of C.I. Pigment Yellow is different to that of all others