1630HYDROGENO-PYROPHOSPHATE TRIPOTASSIQUE TRIHYDRATE 2,489 A correspondant ~ une liaison hydrog~ne tr~s courte. Par ailleurs on remarque que l'oxyg~ne du pont intervient dans la coh6sion de la structure en formant une liaison 61ectrostatique avec un atome de potassium. Les The alkaloid morphine crystallizes as hydrochloride trihydrate in the orthorhombic space group P21212~ with the unit-cell dimensions a= 13.019, b= 20.750, c= 6.941 A. Three-dimensional data were collected on an automatic linear diffractometer. The structure was determined by the heavy-atom technique and the positions of the hydrogen atoms were established by difference syntheses. Refinement by full-matrix least-squares methods resulted in a final R value of 0.046 for 1089 observed reflexions. The morphine molecules, connected by N-H...O hydrogen bonds, form chains about the 2~ axes parallel to a and the chains are connected via water molecules and chloride ions. The packing of the molecules and the hydrogen bonding system are very similar to those earlier found in the structures of morphine hydroiodide dihydrate and codeine hydrobromide dihydrate.
The drug dextromethorphan crystallizes as the hydrobromide monohydrate in the orthorhombic space group P212121 with cell dimensions a = 9.217, b = 27.398, c = 7.063 A. The structure was determined by the heavy-atom technique with 2050 observed symmetry-independent reflexions collected by diffractometry. Full-matrix least-squares refinement yielded a final R value of 0.057. The absolute configuration of the cation, determined from the anomalous dispersion of Br-, was found to be opposite to that of natural (-)-morphine. In the crystal the packing of the cations is determined by hydrogen bonds; the piperidine NH ÷ acts as donor to the water molecule which in its turn forms two OH... Br-bonds running in infinite zigzag chains parallel to a.
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