Sr₉La₂(WO₆)₄ containing [WO₆] octa-hedra.

Area of Science:

• Solid-state chemistry
• Crystallography
• Materials science

Background:

• Tungstate compounds are of interest due to their diverse structural and functional properties.
• Understanding the crystal chemistry of complex oxides like strontium lanthanum tungstates is crucial for developing new materials.

Purpose of the Study:

• To synthesize and characterize a novel strontium lanthanum tungstate compound, Sr₉La₂(WO₆)₄.
• To determine the crystal structure of Sr₉La₂(WO₆)₄ using single-crystal X-ray diffraction.
• To analyze the structural features and relationships to known structure types.

Main Methods:

• Polycrystalline sample preparation via solid-state reaction of SrCO₃, WO₃, and La₂O₃ at 1473 K.
• Single-crystal growth by reheating the sample at 1673 K.
• X-ray crystal structure analysis of a single-crystal grain.

Main Results:

• Sr₉La₂(WO₆)₄ was successfully synthesized and crystallized in the tetragonal space group I4₁/a.
• The compound is isotypic with Sr₁₁(ReO₆)₄, with four formula units per unit cell.
• The structure consists of isolated [WO₆] octahedra and mixed Sr/La sites coordinated by 8-12 oxygen atoms, describable as a double-perovskite related structure with vacancies.

Conclusions:

• The crystal structure of Sr₉La₂(WO₆)₄ was elucidated, revealing a unique arrangement of tungstate octahedra and mixed cation sites.
• The findings provide fundamental insights into the structural diversity of tungstate-based materials.
• This work contributes to the understanding of complex oxide structures and their potential applications.