Understanding Crystal Structures: How to Read Table Data for Modeling in VESTA

  • Thread starter Thread starter dipole
  • Start date Start date
  • Tags Tags
    Reading Table
Click For Summary
SUMMARY

This discussion focuses on interpreting crystal structure data for modeling in VESTA, specifically analyzing a table that describes a cubic crystal with space group P a -3 (SG Number 205). The user seeks clarification on the columns labeled SOF (site occupancy fraction) and H, which relate to the positioning of atoms in the crystal lattice. The conclusion drawn is that the SOF indicates that the As and Se atoms occupy the same site with a 50% occupancy, suggesting a disordered arrangement within the crystal structure.

PREREQUISITES
  • Understanding of crystal structure terminology, including unit cell and space group.
  • Familiarity with VESTA software for crystal modeling.
  • Knowledge of Wyckoff positions and their significance in crystallography.
  • Basic comprehension of site occupancy fractions in crystal chemistry.
NEXT STEPS
  • Research the interpretation of Wyckoff positions in cubic crystals.
  • Learn how to model disordered structures in VESTA.
  • Explore the implications of site occupancy fractions in crystal chemistry.
  • Study the effects of crystal symmetry on atomic arrangements.
USEFUL FOR

Crystallographers, materials scientists, and researchers involved in modeling crystal structures using VESTA, particularly those working with disordered compounds.

dipole
Messages
553
Reaction score
149
Hello, I have a table here which describes the structure of a certain compound, but I'm unsure how exactly to read it.

Unit Cell 5.940(3) 5.940(3) 5.940(3) 90.0 90.0 90.0
Vol 209.58
Z 4
Space Group P a -3
SG Number 205
Cryst Sys cubic
Pearson cP12
Wyckoff c a
Red Cell P 5.94 5.94 5.94 90 90 90 209.585
Atom # OX SITE x y z SOF H
As 1 -1 8 c 0.383 0.383 0.383 .5 0
Se 1 -1 8 c 0.383 0.383 0.383 .5 0
Ir 1 +2 4 a 0 0 0 1. 0

I am unsure what the columns SOF and H might mean. I want to model this crystal in a program, but as you can see the As and Se atom are located in the same position, so my guess is that they somehow alternate with each other, but I'm exactly sure how to put the data in the program. I'm using VESTA if anyone's familiar with it.

Any help would be appreciated. Thanks.
 
Chemistry news on Phys.org
My best guess is SOF = site occupancy fraction. So, half of those sites are Se, and half are As. It may be disordered, so the Se and As are randomly distributed in the crystal.
 

Similar threads

Undergrad Miller indices and periodic boundary conditions
  • · Replies 0 ·
Replies
0
Views
3K
Graduate Understanding the Unit Cell of Wurtzite Crystal Structure: A Brief Overview
  • · Replies 1 ·
Replies
1
Views
4K
Graduate Avg. Num. Probes to Insert in Hash Table w/ Random Collision Res. Strat.
  • · Replies 3 ·
Replies
3
Views
4K
Fortran Why Am I Getting an 'Out of Range in G Table' Error in FORTRAN?
  • · Replies 1 ·
Replies
1
Views
3K
How do I calculate the density of calcium from atomic radius?
  • · Replies 11 ·
Replies
11
Views
17K
Flushing Data in Loop? -- Keep Entering Empty Space
  • · Replies 6 ·
Replies
6
Views
2K
Fortran FORTRAN- How to read a non-uniformly formatted text file
  • · Replies 3 ·
Replies
3
Views
4K
How to Write a C Program for DNA Sequencing?
  • · Replies 5 ·
Replies
5
Views
5K
How Does C Manage Memory Addresses and Types?
  • · Replies 7 ·
Replies
7
Views
3K
Mathematica This Week's Finds in Mathematical Physics (Week 241)
  • · Replies 8 ·
Replies
8
Views
5K