This example uses the raw hkl data used to determine the crystal
structure of Cs2TiSi6O15
as published in I.E. Grey, R.S. Roth, M.L. Balmer,
Journal of Solid State Chemistry, 131, 38-42 (1997).
The starting information that is normally known before starting WinGX is:
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Run WinGX to bring up the following Menu Bar
From the menu, select Files, Job Paths, Move Working Directory and select the hkl file from which you are going to work with.
A Window will pop up that No (shelx) INS file was found for the Structure. This is OK as the Shelx INS file has not been created yet.
A summary window will then appear which has no information in it yet.
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(In the latest WinGX 1.62, running Model, PRELIM, AUTOSTART, will
automatically try and do everything for you (prompting for confirmation of
suggested space group and cell contents, etc) then automatically try and
solve the structure in Shelxs. The following is done the slower way but
gives more checking information)
To Model, PRELIM, E-statistics, to start off an initial look at the HKL data
If you have absorption corrected your data by various methods (i.e., gaussian, analytical, etc). Select the dataset you consider most appropriate.
When prompted, input the basic cell information, and Molecular Formula. Then select Estimate Z to have WinGX estimate the number of Formula units in the cell. (WinGX does quite an excellent job estimating Z. However, if is estimates incorrectly, it is up to the user to correct it).
WinGX will then look at the HKL data then output a number of graphs for you to evalulate by eye.
WinGX will then give you a warning that E-stats are just a guide.
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Now we want to determine the spacegroup. Thus via the
menu, select Model, PRELIM, Assign Spacegroup.
WinGX will then run Patrick McArdle's ABSEN software to try and suggest the most likely spacegroups. WinGX will bring up a screen prompting you to confirm or change the cell constants and cell type
WinGX will then recommend a space group (in this case, correctly C 2/c. You can over-ride this if you want and either directly enter or browse the list of possible spacegroups.
Click OK to terminate this dialog box so you can continue on to via the Model, PRELIM menu system to create the starting Shelx and CIF files.
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Now we want to initialise the Shelx INS and CIF files so
we can then make a start on solving the structure. Thus via the
menu, select Model, PRELIM, Initiliase Files.
WinGX will bring up a GUI window to input the extra information it needs to create the starting Shelx file and CIF files. Click on whether you are using F's or Fsquares, temperature of the data collection, X-rays Neutrons and the Wavelength being used.
Then select the Crystal Information tab and input the crystal colour and dimensions (and redo Z if you wish).
Fill in as much software information as you can at this point.
Press OK and WinGX should then prompt with a message stating.
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You may now continue on to either do various types of absorption correction or try and solve the structure using the available software, Shelxs, Sir or DIRDIF. |