The crystal and molecular structure of 1,8-dioxo-9-(o-nitrophenyl)-1,2,3,4,5,6,7,8-octahydroxanthene

The crystal structure of the title compound is described. The compound crys tallizes in monoclinic space group P2(1)/a with Z=4. The unit cell dimensio ns are a = 10.809(2), b = 9.998(2) and c = 14.855(3) Angstrom, V = 1592(1) Angstrom(3), D-cal = 1.399 g/cm(3). The central ring of the octahydroxanthe ne moiety is slightly folded and the two outer rings are in sofa conformati ons. Due to the pi-conjugation there is an electron delocalized stretch. Th e phenyl ring of the 2-nitrophenyl substituent is perpendicular to the octa hydroxanthene ring system.