[Ifeffit] Re: about atoms.inp data of As2O3 (arsenious oxide)

Matthew Marcus mamarcus at lbl.gov
Mon May 8 11:36:43 CDT 2006


Mincryst has two crystal forms of As2O3.  One of these is claudetite, for 
which they give the following data:
1, t-claudetite, form I, f-arsenolite

As(2)O(3)
Monoclinic  P 2(1)/n  Z = 4
         F.Pertlik (1978)
        * Mh. Chem., 109, 277-282

  Lattice parameters (cub. angs.,degr.):

             a =   5.2500   alpha =   90.00
             b =  12.9900   beta  =   93.88
             c =   4.5300   gamma =   90.00

   Co-ordinates, thermal parameters, occupation for atomic positions:

NoP   x/a     y/b     z/c    B(j)   atom  / occupation

  1  0.2577  0.1017  0.0423   0.00   As    = 1.00
  2  0.3584  0.3504  0.0043   0.00   As    = 1.00
  3  0.4353  0.2190  0.0624   0.00   O     = 1.00
  4  0.6613  0.3975  0.1513   0.00   O     = 1.00
  5  0.9608  0.1381  0.1452   0.00   O     = 1.00

  Full unit cell contains         20  positions


   X-ray density (g/cm cub.)   =      4.26

and the other is arsenolite:

Cubic  F d3m  Z = 16
Ref.Str.:
         Pertlik F. (1978)
        * Czech. J. Phys., B28, 170-176

  Lattice parameters (cub. angs.,degr.):

             a =  11.0740   alpha =   90.00
             b =  11.0740   beta  =   90.00
             c =  11.0740   gamma =   90.00


   Co-ordinates, thermal parameters, occupation for atomic positions:

NoP   x/a     y/b     z/c    B(j)   atom  / occupation

  1  0.8971  0.8971  0.8971   0.00   As    = 1.00
  2  0.1726  0.0000  0.0000   0.00   O     = 1.00

  Full unit cell contains         80  positions


   X-ray density (g/cm cub.)   =      3.87


I don't know which is the more common form or more likely.  Both yield 
3-coordinate As.
    mam

----- Original Message ----- 
From: "Bruce Ravel" <bravel at anl.gov>
To: "Lee, Ji-Hoon" <jhlee2 at gist.ac.kr>; "XAFS Analysis using Ifeffit" 
<ifeffit at millenia.cars.aps.anl.gov>
Sent: Monday, May 08, 2006 8:38 AM
Subject: [Ifeffit] Re: about atoms.inp data of As2O3 (arsenious oxide)


> On Monday 08 May 2006 08:47, you wrote:
>> I am a Ph.D. student in Gwangju Institute Science and Technology, South
>> Korea. I have been tried to analyze my EXAFS sample with reference of 
>> As2O3
>> (arsenious oxide) obtained from "The Atoms.inp Archive
>> (http://cars9.uchicago.edu/~newville/adb/search.html). But I could not 
>> run
>> the feff in the Artemis (version 0.8.006) successfully with the As2O3 
>> atoms
>> file. Could you let me know how to solve the problem? It would be very
>> honor to me if you let suggest a clue for the problem, sir.
>
> Ji-Hoon,
>
> This is the sort of question that should be asked on the Ifeffit mailing 
> list,
> so I am taking the liberty of CCing my answer there.
>
> I agree that the input file for As2O3 from the database is wrong.  It
> generates an obviously incorrect list of coordinates.  You need to go to 
> the
> crystallography literature and find the correct data for that structure.
>
> There is nothing wrong (at least with respect to this question!) with
> Artemis.  It seems likely that the problem is with the reliability of the 
> data
> for As2O3 in the database.
>
> B
>
>
> -- 
> Bruce Ravel  ---------------------------------------------- bravel at anl.gov
>
> Molecular Environmental Science Group, Building 203, Room E-165
> MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007
>
> Argonne National Laboratory         phone and voice mail: (1) 630 252 5033
> Argonne IL 60439, USA                                fax: (1) 630 252 9793
>
> My homepage:    http://cars9.uchicago.edu/~ravel
> EXAFS software: http://cars9.uchicago.edu/~ravel/software/
>
>
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