A method for seeking an appropriate model of complicated organic crystal structure based on two-dimensional least squares refinement

In crystals of complicated organic substances of all atoms having approximately the same weights most of the atoms overlap in projections and therefore it is impossible to verify the correctness of a proposed model of structure and to improve it by Fourier projections. As the three-dimensional Fourier syntheses are rather time-consuming, two-dimensional least squares refinement of coordinates and individual temperature factors is used.The described method is appropriate for selecting the best model of crystal structure from several which come into consideration.The paper was presented at 9. Diskussionstagung für Kristallkunde der Deutschen Mineralogischen Gesellschaft held in Bonn in April 1967.The author wishes to thank Dr. B. Sedláek for his continuous interest, Dr. D. Oenáková for kindly supplying her least squares program and D. Kotíková for careful preparation of the drawings.