K. Peters et al., Crystal structure of (1 ' R*,3R*,3aR*,4S*,8aR*)-dimethyl 1 ',3-epoxy-decahydro-3,5-(2 '-oxapropanylidene)-8-oxo-azulene-3a,4-dicarboxylate, C12H12O3(COOCH3)(2), Z KRIST-NEW, 214(1), 1999, pp. 91-92
C16H18O7, monoclinic, P2(1)/c1 (No. 14), a = 11.186(1) Angstrom, b = 8.655(
1) Angstrom, c = 16.258(2) Angstrom, beta = 109.37(1)degrees, V = 1484.9 An
gstrom(3), Z = 4, R-gt(F) = 0.082, R-w(F) = 0.085, T = 293 K.