STRUCTURE OF THE HIGH-MELTING PHASE OF PETROSELINIC ACID

cis-6-Octadecenoic acid, C18H34O2, M(r) = 282.47, triclinic, P1BAR, a = 5.359 (1), b = 8.874 (2), c = 41.391 (5) angstrom, alpha = 90.49 (1), beta = 89.12 (2), gamma = 113.81 (2)-degrees, V = 1800.7 (6) angstrom 3, Z = 4, D(x) = 1.04 g cm-3, lambda(Cu K-alpha) = 1.5418 angstrom, mu = 4.7 cm-1, F(000) = 632, T = 263 K, R(F) = 0.068, wR(F) = 0.087 for 3927 unique observed reflections with F > 3-sigma(F). There are two crystallographically independent molecules A and B in the asymmetric unit. The methyl-terminal hydrocarbon chains of both molecules form a monoclinic subcell with parallel skeletal planes. Torsion angles of the C-C = C-C olefin group are 91, 1 and 130-degrees from the carboxyl side for molecule A, and 137, 1 and 119-degrees for molecule B.