Ba4Ta2O9 oxide prepared from an oxalate-based molecular precursor-characterization and properties

Area of Science:

• Inorganic Chemistry
• Materials Science
• Solid State Chemistry

Background:

• Oxalate-based compounds serve as precursors for advanced materials.
• Barium tantalate (Ba-Ta) oxides are of interest for their dielectric and ferroelectric properties.
• The synthesis of specific polymorphs, especially at ambient conditions, remains challenging.

Purpose of the Study:

• To synthesize and characterize a novel heterometallic oxalate-based compound.
• To investigate the thermal conversion of this precursor into a mixed-metal oxide.
• To explore the properties of the resulting γ-Ba4Ta2O9 phase.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Infrared (IR) spectroscopy and thermal analysis (TGA/DSC).
• Density functional theory (DFT) calculations for electronic structure.

Main Results:

• A novel 3D coordination polymer, {Ba2(H2O)5[TaO(C2O4)3]HC2O4}·H2O, was successfully synthesized.
• Thermal treatment up to 1200 °C resulted in the formation of the γ-Ba4Ta2O9 phase with a 6H-perovskite structure.
• The γ-Ba4Ta2O9 phase, typically unstable at room temperature, was obtained and its spectroscopic, optical, photocatalytic, and electrical properties were investigated.

Conclusions:

• The synthesized oxalate compound serves as an effective molecular precursor for γ-Ba4Ta2O9.
• The study provides insights into the stabilization of the high-temperature γ-Ba4Ta2O9 polymorph.
• Investigated properties suggest potential applications for this novel barium tantalum oxide phase.