[Pw_forum] About the atomic radii used for visuliztion of a structre.

[Tone Kokalj]

On Mon, 2008-09-08 at 17:28 +0800, Hongsheng Zhao wrote:

> My issue is as follows:
> 
> What's relationship between the atomic radii used for visuliztion of a 
> structre and the atomic real radii of the atoms/ions?  This issue arise 
> from the fact that I find many crystal visuliztion tools, i.e.,  diamond, 
> rasmol, and etc., don't treat the atomic radii according to the real radii
>  of the atoms/ions belong to the structure, never so much as proportionate
>  to the counterpart real radii.

What should we choose for the real atomic radius: atomic, covalent,
ionic, wan der Waals, ... 

Usually the vizualizers do plot atoms according to some preset radii, 
but there are many types of radii. Say that they are plotted according 
to covalent radii, and that you are plotting some ionic crystal. 
The radii will not be what you expect ... Of course you know it is ionic, 
but the dummy visualizer do not, and merely plots the radii from preselected table.

Some programs do have the possibility to choose among different types of radii, 
and even to set the radii manually.

Regards, Tone

-- 
Tone Kokalj <tone.kokalj at ijs.si>
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel:
+386-1-477-3523 // fax:+386-1-477-3822)