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Synthesis, properties, and complex crystal structure of Th2Se5
Brian J Bellott1, Christos D Malliakas, Lukasz A Koscielski
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
Inorganic Chemistry
|December 29, 2012
Summary
The synthesized thorium selenide (Th(2)Se(5)) exhibits a modulated crystal structure and semiconductor properties. Its band gap is 0.37 eV, suggesting potential electronic applications.
Area of Science:
- Solid State Chemistry
- Materials Science
- Crystallography
Background:
- Thorium selenides are compounds with potential applications in materials science.
- Understanding the crystal structure and electronic properties of these materials is crucial for their development.
Purpose of the Study:
- To synthesize and characterize the crystal structure of thorium selenide (Th(2)Se(5)).
- To investigate the electronic properties, including electrical resistivity and band gap, of Th(2)Se(5).
- To compare the structure of Th(2)Se(5) with Neptunium selenide (Np(2)Se(5)) to infer oxidation states.
Main Methods:
- Single-crystal X-ray diffraction for structure determination.
- Electrical resistivity measurements to analyze semiconductor behavior.
- Spectroscopic measurements to determine the band gap.
Main Results:
- Th(2)Se(5) was synthesized and its modulated crystal structure solved in the monoclinic super space group P2(α0γ)0.
- The structure contains infinite Se-Se chains with varying bond distances.
- Th(2)Se(5) is a semiconductor with a band gap of 0.37(2) eV and thermally activated resistivity (activation energy 0.40(1) eV).
Conclusions:
- The modulated structure of Th(2)Se(5) contrasts with the non-modulated structure of Np(2)Se(5), suggesting a formal oxidation state of 4+ for Np.
- Th(2)Se(5) exhibits semiconductor properties with a defined band gap, indicating potential for electronic device applications.
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