Crystal data for a second polymorph (β) of C.I. Pigment Red 1,1-[(4-nitrophenyl)azo]-2-naphthol

The preliminary single-crystal data and powder pattern are given for a second polymorph of C.I. Pigment Red 1, C₁₆H₁₁N₃O₃. The powder pattern has been indexed using the single-crystal dimensions; the problems of multiple indexing have been reduced by comparison with single-crystal intensities.