Crystal structure of chain silicate Cs₃LuSi₃O₉

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Crystallography

Background:

• Silicate compounds are crucial in materials science.
• Rare-earth silicates exhibit diverse structural and functional properties.
• Caesium-based compounds offer unique ionic characteristics.

Purpose of the Study:

• To synthesize and characterize a new caesium lutetium(III) silicate.
• To determine the crystal structure of Cs3LuSi3O9.
• To investigate its structural relationship with known rare-earth germanates.

Main Methods:

• High-temperature solid-state reaction synthesis at 1273 K.
• Single crystal growth from a melted pellet.
• X-ray diffraction analysis for crystal structure determination.

Main Results:

• Successfully synthesized caesium lutetium(III) silicate, Cs3LuSi3O9.
• Determined the crystal structure: ortho-rhom-bic space group Pna21.
• Identified a single-chain silicate structure with [Si6O18]12- chains parallel to [011].
• Observed octahedral coordination of Lu3+ ions and Cs+ ions in framework voids.
• Established structural analogy with Cs3REGe3O9 (RE = Pr, Nd, Sm-Yb).

Conclusions:

• Cs3LuSi3O9 represents a new member of the Cs3RESi3O9 family.
• The structure features a 3D framework built from silicate chains and coordinated cations.
• This synthesis expands the known structural diversity of rare-earth silicates.