Crystal structure of 2-(3-amino-2,4,4-tricyano-buta-1,3-dienyl)-thiophene

The title compound (C11H6N4S) crystallizes in the orthorhombic space group Pbca with a = 23.561(4) Angstrom, b = 7.064(1) Angstrom, c = 13.018(3) Angstrom, Z = 8; D-x = 1.387(1) g.cm(-3); R = 0.073 for 1697 observed reflections [F-2 greater than or equal to 2 sigma(F-2)]. The interesting feature is disorder in the crystal structure resulting from the existence of two isomeric molecules with interchangable carbon and sulfur positions, occuring at random but with equal probability in the structure