Gd. Potts et W. Jones, AN INVESTIGATION INTO THE SOLID-STATE BEHAVIOR OF ANTHRAQUINONE AND ITS DERIVATIVES, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 240, 1994, pp. 217-224
The principle packing motif observed in anthraquinone is apparent in a
number of halogenated derivatives and extends to very large polycycli
c systems. Halogenation of the anthraquinone nucleus generates steric
hindrance, which in extreme situations is manifested by the adoption o
f nonplanar molecular conformations.