Using Electron Diffraction to Solve the Crystal Structure of a Laked Azo Pigment

The structure of the ζ phase of Pigment Red 53:2 was solved using electron diffraction data. The unit cell determination appeared to be more complicated due to twinning of the crystals. A series of electron diffraction patterns derived by sequential crystal tilt around a main axis consisted of two complementary sequences originating from different twin domains. Subsequent assignment of the obtained zones to the two individuals allowed zone indexing and lattice parameter determination. The structure was solved by intensity distribution analysis in selected experimental electron diffraction patterns. Finally, the derived structure was refined against X-ray powder data.