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Tutorials and Examples

Platon (Shelx Compatible) Structure Analysis Toolkit Software by Ton Spek

Using Platon's Addsym to find missing Symmetry and possibly correctly assign the spacegroup based on the atom positions

The CCP14 Homepage is at http://www.ccp14.ac.uk

[Tutorials page] | [Platon Tutorial Index]
[Platon Introduction] | [Obtaining Platon] | [Installing and Running Platon]
[Starting out with Platon] | [Platon Runthroughs] | [Platon's Addsym]

Platon's Addsym Manual - by Ton Spek


One of the mega powerful features of Platon is the Addsym algorithm "(building on Yvon LePage's powerful published MISSYM (C) algorithm)" which checks the spacegroup based on the positions of the atoms and looks for missing symmetry. This can be very useful not only for single crystal problems but also powder diffraction based structures where the indexing or solving algorithms may have given a lower symmetry. In some cases, it is preferable to solve structures in low symmetry spacegroups such as P1 (such as powder based simulated annealing/ real space algorithms). Platon can then possibly pick up the symmetry and assign a correct spacegroup. Addsym is "also" applicable to inorganic structures, mineral structures and structures solved and refined using powder diffraction methods.

Platon makes this type of check quite trivial and easy to do for all structures. More compelling reasons for routinely do this are in the following webpage on "Cases of Pseudo Symmetry or real missed Symmetry in the CSD".


The following example is a small inorganic phase. Though of course this can be applied to much larger structures.

If running Platon for UNIX, just type platon filename.ins, platon filename.res or platon filename.cif to enter the Shelx or CIF file.

For Platon for Windows, open a structure file using the File, Open command.

File formats supported by WinPLATON


Enter the Platon MENU option using the Platon, PLATON Menu to be able to access the common Platon command options.

File formats supported by WinPLATON


Select ADDSYM (under Symmetry) and hang back and let Platon do the rest. In this case, Platon has found some extra symmetry.

Addsym finished running


The results are in the "Platon Dialog Window", examine then and determine for yourself if Platon is onto something.

Addsym Output in the Dialog Window


If you instead run Addsym-PLT, a structural output will be generated to the screen. Or the resulting structure can be outputted directly to a Shelx *.res file using the ADDSYM-SHX menu option.

Addsym-PLT graphical structure output Window


[Tutorials page] | [Platon Tutorial Index]
[Platon Introduction] | [Obtaining Platon] | [Installing and Running Platon]
[Starting out with Platon] | [Platon Runthroughs] | [Platon's Addsym]

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