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Tutorials and Examples

Automated Single Crystal Structure Solution Using Sir2002

If Sir2002 does not solve by default (in this case on a polymeric inorganic) - making use of the RELAX option

The CCP14 Homepage is at http://www.ccp14.ac.uk
[CCP14 Tutorials page] | [Sir97/2002 Tutorial Index] | [EXPO]
[WinGX] | [Crystals] | [Platon/System S]
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).

Sir97 (and soon for Sir2002) can be spawned transparently from the following single crystal suites (freely available for students and academics) :

Note: a feature of Sir97 and Sir2002 that may not be obvious is that if it fails to solve on the first trial, you should just leave it run. Sir2002 by default goes through the first 200 Trials.

The following example structure is of a Cesium Titanium Silicate.

Be wary that Sir2002 assumes you have put in the correct chemistry (or close to the correct chemistry). When in doubt, perform an elemental analysis. It is not that uncommon for other elements to be present in inorganic crystals, especially if a flux of different composition has been used to grow the crystals.

Obtaining the data

Click here to obtain the zipped Cesium Titanium Silicate hkl data and Sir2002 starting file. (as published in I.E. Grey, R.S. Roth, M.L. Balmer, Journal of Solid State Chemistry, 131, 38-42 (1997))

First method of starting out with Sir2002

Copy over an existing Sir2002 *.sir file. Open the file in your favourite text editor and modify the cell, hkl file, spacegroup and contents information as per the following. By default, Sir2002 assumes F-square data. While the "Fosquare" command used in Sir97 is now redundant in Sir2002, it will not cause any harm having it in. 
%window
%structure    eg1scrat
%init
%job   XYZN file = SHELXL INS file, from DIRDIF output for EG1SCR
%data
         Cell     13.386   7.423  15.134  90.000 107.710  90.000
         Space   C 1 2/c 1
         Content   Cs    8 O    60 Si   24 Ti    4
         Reflections   eg1scrat.hkl
         Format  (3i4,2f8.2)
         Fosquare
%continue

Second method of starting out with Sir2002

Run Sir2002, and from the top left menu select, File, New to give the following GUI screen. Enter the directory where the hkl data is located, then fill in the information that Sir2002 requires.

Run Sir2002 to bring up the starting screen

From the top left menu select, File, Load and Go. Select the *.sir file and then select the Go ICON. You can edit the information before trying to solve the structure by selecting the Edit ICON.

However, Sir2002 may give something like the following that is not a suitable result. It actually looks like it has solved, but it may not look that obvious. At the time, this was a new structure type, so firstly there is the problem of solving, secondly there is the problem of recognising that the structure has been solved.

Trying the RELAX function

In this example, Sir2002 does not solve the structure in default mode. In the Sir2002 help system, there are hints on what to try next. Select the top right Help menu for the HTML based help.

In this case, we will try the RELAX function (which is described in the manual). Via the top menu, select Modify Setup, and then select the Use RELAX Procedure.

After selecting Use RELAX Procedure, now select the Go Icon. Sir2002 now solves the structure as shown below (in this case on the first cycle).

Exporting a solved structure from Sir2002 into another format

Using the top menu, select File, Export and choose your desired file format. (Shelx, Caos, Crystals, Schakal, etc)

[CCP14 Tutorials page] | [Sir97/2002 Tutorial Index] | [EXPO]
[WinGX] | [Crystals] | [Platon/System S]
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