Why Do Sulfurous Compounds Show Different Peaks in X-ray Absorption Spectra?

Click For Summary
SUMMARY

The discussion focuses on the interpretation of X-ray absorption spectra of iron and sulfur compounds, specifically addressing the differences in peak formation. The article "Phase Composition of Iron Oxide Nanoparticles Studied Using Hard X-ray Absorption Spectroscopy" explains that the oxidation states of iron contribute to the Fe-K absorption edge shift, while tetrahedral conformation results in a pre-peak. In contrast, the article "In Situ Analysis of Sulfur Species in Sulfur Globules" raises questions about the dual peaks observed in sodium thiosulfate, attributed to differing oxidation states of sulfur, which contrasts with the single peak observed in magnetite despite its mixed oxidation states.

PREREQUISITES
  • Understanding of X-ray absorption spectroscopy principles
  • Knowledge of oxidation states in chemical compounds
  • Familiarity with iron oxide compounds such as FeO, hematite, and magnetite
  • Basic concepts of sulfur chemistry, particularly thiosulfate
NEXT STEPS
  • Research the principles of X-ray absorption spectroscopy in detail
  • Study the oxidation states of sulfur in various compounds
  • Explore the structural differences between tetrahedral and octahedral coordination in minerals
  • Investigate the specific absorption features of sodium thiosulfate in X-ray spectroscopy
USEFUL FOR

Chemists, materials scientists, and students studying X-ray absorption spectroscopy, particularly those interested in the analysis of iron and sulfur compounds.

feelice
Messages
1
Reaction score
0
Homework Statement
Interpretation of X-ray absorption spectra
Relevant Equations
none
Hey guys :)

actually my homework was just to research the absorption spectra of some iron compounds and some sulfurus compounds - to which I have the answer. I just dont understand it. In this arcticle, fig 2b: "Phase Composition of Iron Oxide Nanoparticles Studied Using Hard X-ray Absorption Spectroscopy" the needed FeO, hematite and magnetite are listet. It was explained to the course, that roughly the oxidation state is added to the shift of the Fe-K-absorption edge which fits, also that tetrahedral conformation will lead to a pre peak, which also fits.
Now we come to the sulfurous compounds. In this article, fig.3b: "In Situ Analysis of Sulfur Species in Sulfur Globules Produced from Thiosulfate by Thermoanaerobacter sulfurigignens and Thermoanaerobacterium thermosulfurigenes", the sodium thiosulfate is somehow not fitting in for me. Why does ist have two main peaks - if you say because on sulfur has the oxidation state -1 and the other plus 5, then why does magnetite only have on peak even though it has one iron in oxidation stat +2 and the other two in +3. Why do we split in thiosulfate?

It really bothers me and I would be very glad if someone could help me solve this puzzle.
 
Physics news on Phys.org
feelice said:
Homework Statement: Interpretation of X-ray absorption spectra
Relevant Equations: none

In this arcticle, fig 2b:

do you have links to the 2 articles you are reading, please