BaRh2Si9--a new clathrate with a rhodium-silicon framework

Area of Science:

• Solid State Chemistry
• Materials Science
• Inorganic Chemistry

Background:

• Intermetallic clathrates represent a fascinating class of compounds with unique structural and electronic properties.
• The synthesis and characterization of new clathrate structures are crucial for expanding the library of functional materials.

Purpose of the Study:

• To synthesize and characterize a new semiconducting intermetallic clathrate, BaRh2Si9.
• To elucidate the crystal structure and electronic properties of this novel compound.

Main Methods:

• High-temperature synthesis reaction of Barium disilicide (BaSi), Rhodium (Rh), and Silicon (Si) at 950 °C.
• X-ray diffraction for crystal structure determination (space group C2/c, mC48).
• Band structure calculations and quantum chemical calculations for electronic property analysis.

Main Results:

• Successful synthesis of BaRh2Si9, a new intermetallic clathrate compound.
• Determination of its crystal structure, revealing a covalently bonded Rh-Si framework with encapsulated Ba atoms.
• Characterization as a diamagnetic p-type semiconductor with a calculated band gap of 0.12 eV.
• Quantum chemical calculations indicated charge distribution with Ba(+1.3), Rh(-1), and varying charges on Si atoms.

Conclusions:

• BaRh2Si9 is a novel diamagnetic p-type semiconductor with a unique clathrate structure.
• The electronic properties are consistent with band structure calculations and charge distribution analysis.
• The study contributes to the understanding of structure-property relationships in intermetallic clathrates.