[Wien] Space group P4(2)/nmc (137)

[Víctor Luaña Cabal]

On Thu, Mar 26, 2015 at 02:51:13PM +0100, Ary Ferreira wrote:
> Please,
> 
> I'm trying to use the makestruct script to build the structure of
> tetragonal zirconia. According to [Acta Cryst. (1962). 15, 1187], the space
> group is P4(2)/nmc (137), the parameters are a = 3.64 Ang., c =5.27 Ang.,
> and there are 6 atomic positions in the full cell:
> 
> [symbol] [id] [WP] [x] [y] [z]
> Zr 1 2a 0.0000 0.0000 0.0000
> Zr 2 2a 0.5000 0.5000 0.5000
> O 1 4d 0.0000 0.5000 0.1850
> O 2 4d 0.5000 0.0000 -0.1850
> O 3 4d 0.0000 0.5000 0.6850
> O 4 4d 0.5000 0.0000 0.3150

Ary,

Let's us forget programs. In the bilbao crystallographic server
you find:

space group P4(2)/nmc (137) , Wyckoff positions:

<http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list>

(2a) (3/4,1/4,3/4),(1/4,3/4,1/4)

Does not coincide with your positions, so the setting is not in the
same origin. However, the same page lets you displace the origen to the
reference of your data:

(2a) - (0.75,0.25,0.75) -> (0,0,0)

Now continues ...

This page lets you decide any origin:

<http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-chbasis?what=wpos&gnum=137&gor=t>

Best regards,
             Dr. Víctor Luaña
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