Ab initiostructure determination of the Γ form ofD-sorbitol (D-glucitol) by powder synchrotron X-ray diffraction

A high-resolution powder synchrotron X-ray diffraction pattern of the Γ form of D-sorbitol has been recorded at 293 K on the BM1B beamline at the ESRF (Grenoble). The starting model of the structure was found by Monte Carlo simulated annealing. The final structure was obtained through Rietveld refinements performed with soft restraints on interatomic bond lengths and angles. The symmetry is orthorhombic, space group P 2 1 2 1 2, with 12 molecules within the cell a = 24.3012 (2), b = 20.5726 (2), c = 4.8672 (1) Å, V = 2433.30 (3) Å 3 , Z ′ = 3, 36 non-H independent atoms. Crystalline cohesion between neighbouring molecules is achieved by three networks of O—H...O hydrogen bonds. The width of the Bragg peaks is interpreted through a microstructural approach in terms of anisotropic strain effects.