TOWARDS THE SOLUTION OF ORGANIC CRYSTAL STRUCTURES BY POWDER DIFFRACTION
S. Pagola and P. W. Stephens
Department of Physics and Astronomy, State University of New York at Stony Brook, New York 11974-3800, U.S.A.
Keywords: powder diffraction-simulated annealing-molecular crystals
As a part of a program to develop and improve techniques for the solution of crystal structures from powder data, we have collected data sets for the following four compounds: (I) 2-amino-4,5-dimetoxyacetophenone (C10H13NO3); (II) 3-amino-5-mercapto-1,2,4-triazole (C2H4N4S); (III) 1,4-benzenedimethanol (C8H10O2); 3-aminoquinoline (C9H8N2).
They have been indexed to the unit cells and (tentative) space
groups listed below:
| Compound | a (A) | b (A) | c (A) | b (degrees) | Space. Group | Z |
| I | 13.00321(4) | 6.87013(2) | 11.51976(3) | 108.3306(2) | P21/n | 4 |
| II | 9.8518(2) | 12.3866(2) | 8.0075(1) | 102.175(1) | P21/c | 8 |
| III | 9.8429(2) | 15.4836(3) | 4.84511(7) | 101.1988(8) | P21/n | 4 |
| IV | 12.7300(4) | 7.7438(2) | 7.6473(2) | - | P21 21 21 | 4 |
During the recent past years important advances in the development of computational techniques for the prediction of organic crystal structures have been done, and results from ab-initio [1-3], or based in partial X-ray diffraction data [4], calculations have been shown.
We solved the structures I, III and IV using the simulated annealing technique [5]. In the mean time, they may provide useful tests for programs to predict the structures of molecular crystals, e.g., ref. 1-4.
Research performed at the N.S.L.S., Brookhaven National
Laboratory, which is supported by the US D.O.E., Division of
Chemical Sciences and Division of Materials Sciences. This work
was supported by U. S. NSF Grant No. DMR95-01325. The SUNY X3
beamline at the National Synchrotron Light Source is supported by
the Division of Basic Energy Sciences of the US D.O.E .
(DE-FG02-86ER45231).