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" To: "Lee, Ji-Hoon" ; "XAFS Analysis using Ifeffit" 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@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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