cis-Inositol monohydrate, C6H12O6.H2O, crystallizes in the monoclinic space group P 21/n [a 9.900(8), b 9.296(8), c 17.795(15) Ǻ, β 90.5(1)°, Z 8]. The normalized structure factors Eh have an atypical statistical distribution, and attempts to solve the structure by direct methods (triplet relationships) were unsuccessful. The structure was ultimately solved by Patterson and Fourier methods, and was refined by full-matrix least squares [Rw = 0.047 for 1665 independent reflections ≥2σ(Imin)]. The cis-inositol molecules have approximately trigonal symmetry, as expected. The difficulties encountered during the structure analysis are explained by the presence of two nearly identical molecules of high symmetry in the asymmetric unit. The independent molecules are related by translational pseudosymmetry, and their orientations are such that all the C-C and C-O bonds in the structure are approximately parallel to a small number of directions.

The crystal structure of iso-eremolactone, C20H2602, a plant product derivative from a new biogenetic series, has been solved by the direct methods of Karle & Hauptman for non-centrosymmetric structures. The space group is P212121, and a= 12.866, b=20.200, c=6"685 A,. The final R value is 0.063. Long sp3--sp 3 carbon-carbon bonds in the structure are associated with a high degree of substitution at the carbon atoms, and also with bond angles which differ considerably from the ideal tetrahedral values. The thermal motion in the structure has a substantial internal component, which results from the lability of bond angles with non-ideal values.