C18H1002, monoclinic, C2/c, a = 10.918 (1),
b = 11.369(1), c = 19.850(1)A, /~= 97.224(7) ° ,
U = 2444.4 A 3, Z = 8, D,n = 1.41 (2), D c = 1.403 Mg
m -3, F(000) = 1072, 2(CuKa) = 1.5418/~, ~t =
0.742 mm -1. 2253 reflections were measured, of which
1039 had significant intensities. Refinement converged
to a final R of 0.045. The molecule is approximately
planar. Ring C is significantly non-delocalized. Bonds
C(3)-C(4) and C(5)-C(6) are short, and indicate
pronounced olefinic character for these bonds
