IN 1935, E. Kordes 1 recognized that LiAl 6 0 8 has nearly a spinel structure, but he observed a large number of extra lines, which he could not explain. A. Hoffman 2 prepared the corresponding compound LiFe 6 0 8 , which again was recognized as having nearly spinel structure. We found 3 that the powo<>r diagrams of LiFe 6 0 8 correspond with a primitive cubic lattice with a lattice constant of 8•33 A. The space group was found to be very probably P4 3 3 (or P4 1 3) and the positions of the atoms (in the notation of the International Tables, 1935) are : P4 3 3 4 Li at 4 (6)

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Crystals of 3,20-bis(ethylenedioxy)-9,10-seco-pregna-5,7,10(19)-triene are monoclinic, space group P21. The lattice constants are a = 7.134, b = 12.281, c= 12-746 A, fl= 93-00 ° and Z= 2. The structure was solved by simultaneous application of direct methods and Patterson-image-seeking methods. The refinement of the structure, using diffractometer data, resulted in an R value of 7-15 %. The triene system of atoms 4, 5, 6, 7, 8, 9, 10, 14, 19, 1 is not planar, but consists of a nearly planar diene system 4, 5, 6, 7, 8, 9, 10, 14 enclosing a dihedral angle with the planar ene system 1, 5, 10, 19. The triene system is cis relative to C(10)-C(5) and trans with respect to C(6)-C(7), C(6) opposing C(9). The chair conformation of ring A is modified from the conformation of this ring in the 4-iodo-5-nitrobenzoate ester of ergocalciferol. C(19)is 0"69 ,~ above the diene system while being 1.2 A below this system in the ester. The conformations of rings A, C, D and the dioxolane rings are described by means of torsion angles and Newman projections.