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The crystal structure of s-glucose has been fully determined. In the elucidation of the structure, extensive use was made of the two-dimensional Patterson function. The refinement of the atomic parameters was carried out by Fourier and least-squares methods.The stereochemical configuration of the molecule, as deduced on purely chemical grounds, has been directly confirmed. The pyranose ring is in the Sachse-lY[ohr trans form, and there is a c/sglycol grouping on C 1 and C~. Some attempt was made to determine the interatomic bond distances with precision; there would appear to be a shortening of the glycosidic and primary hydroxyl bonds compared with the results obtained for C-O bonds in other investigations.

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This note describes a graphical method by means of which it is possible to determine, without any calculation, both the unit-cell dimension and the indices of the reflexions of cubic substances, when the positions of the diffraction lines on the powder photographs are known.For the cubic system sin 2 0 = (h2+ ks+ 19) h~/4a ~, while, for a cylindrical camera, the Bragg angle in degrees is given by 0-90LIAR. Here a represents the cell edge, /5 the distance between corresponding diffraction lines on opposite sides of the nndiffraeted X-ray beam, and R the diameter of the camera.By plotting L as a function of a for a given value of (h2+]c~+l~), we obtain a smooth curve, which gives for this particular choice of indices the relation between the position of the corresponding diffraction line on the photograph and the cell dimension. Doing so for many values of (h~+ ]c9-t -l~), we obtain a chart consisting of a large number of curves, from which we can read, conversely, the indices and the unit-cell dimension of the substance under investigation.