Ab initio structure determination of low-molecular-weight compounds using synchrotron radiation Laue diffraction

The potential of using polychromatic synchrotron radiation for ab initio structure determination of low-molecular-weight compounds is investigated. Three different organic compounds were studied. For each of the structures the cell volume was determined with the aid of a Zr attenuator that was placed in the direct beam to obtain a sharp edge. Space-group determination did not prove to be complicated; it was aided by deconvolution of the multiple spots. Two low-temperature data sets were collected, and it appeared that spot streaking owing to the inherent increase of mosaicity due to freezing was not too detrimental to the application of the Laue method. Although both the values (around 12%) and the final values (around 10%) are higher than usually found in monochromatic experiments, all structures show reasonable geometry. Comparison of one of the structures with a reference structure obtained with monochromatic data shows an r.m.s. deviation between the 21 non-H-atom positions of 0.019 Å.