SHELX computer program

The best approach to date to automatic structure solution is the direct method (DM), introduced by Hauptmann,154 Jerome Karle,155 and Isabella Karle,156 and made possible by efficient computer programs, such as MULTAN (Main,15 Germain,158 and Woolfson59) and SHELX... 

All of this work is nowadays carried out by computer programs (e.g., SHELX-97 [49]). It is advisable, however, to do at least part of it by hand, so that one is familiar with the theory when there are difficulties. 

G. M, Sheldrick SHELX-97, Computer program for the solution and refinement of crystal strucutres. University of Gottingen, Germany 1997,... 

A number of very successful computer programs have heen developed which make use of such techniques to solve crystal stractures. Many of these are highly automated, so much so that one need not necessarily he fuUy aware of the underlying theory to use them. Such programs are SHELX-76 and SHELXS-84 hy G. M. Sheldrick and MULTAN, YZARC, and MAGIC by M. M. Woolfson. ... 

The most recently computed R values from Clemson (Table XII) Indicate that a lower figure can be obtained for a structure that has the same 06 positions within Individual chains but with 06 positions for the center chains being different from 06 positions of the corner chains. However, In the best model from Clemson, the polymer continuity Is disrupted by about 0.2 A at the top of the unit cell due to lack of polymeric constraints In the SHELX program. 

Although the R" values from SHELX are very low, the conventional R values computed with this program are still quite high. Indicating substantial error In gathering the data rather... 

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