AB INITIO CRYSTAL STRUCTURE DETERMINATION FROM LOW TEMPERATURE X-RAY POWDER DATA:THE CHIRAL COMPOUND L-CARVONE. C.Miravitlles*, J.Rius*, J.Sañé*, M.A.Cuevast + & T.Calvet+ (*) Institut de Ciencia de Materials de Barcelona, camp. UAB, O8193-Bellaterra, Spain (+) Fac. de Geologia, Univ. de Barcelona, c/ Marti Franques s/n, Barcelona, Spain

The ab initio structure determination of the chiral compound l-carvone (C₁₀H_l4O) at 218 K is presented. The pattern was measured with CuK[[alpha]]₁ radiation, a position sensitive detector and the sample, liquid at room temperature, included in a glass capillary. The crystal data are: orthorhombic P2₁2₁2₁ with a = 6.8576(3), b = 6.8831(5), c = 19.988(2) Å, Z = 4. The structure was solved by Patterson-search methods using the 44 available integrated intensities. A rigid-body Rietveld refinement with preferred orientation correction and allowing the variation of one torsion angle converged to Rp= 0.03 and Rwp=0.04.

Perspective view of the l-carvone crystal structure at 218 K.