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Solve a small-molecule structure: Difference between revisions
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→Solve the structure with SHELXD: add GS posting
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=== hints from George Sheldrick === | |||
From a [https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=CCP4BB;7190ec63.1111 November 2011 posting]: UNIT specifies the number of atoms of each type in the unit-cell. For such | |||
'small-molecule' problems you should try to get the numbers of heavier atoms | |||
correct, if only CHNO are present any numbers will do. | |||
For such problems I recommend setting FIND to about 70% of the number of atoms | |||
(excluding H) in the asymmetric unit. | |||
The first PLOP number should be approximately the number of atoms (excluding H) | |||
in the asymmetric unit. The second PLOP number should be about 1.2 times this | |||
and the third about 1.4 times it (three PLOP cycles are enough). This allows | |||
the 'peaklist optimization algorithm' to throw out some of the atoms. | |||
You will need data to 1.2A or better (1.0 is much better than 1.2!). The data | |||
should be as complete as possible. | |||
== Refine using [[SHELXL]] == | == Refine using [[SHELXL]] == | ||