Na2[(VO)2(HPO4)2C2O4].2H2O: crystal structure determination from combined powder diffraction and solid-state NMR

Area of Science:

• Inorganic Chemistry
• Materials Science
• Solid-State Chemistry

Background:

• Vanadyl oxalatophosphate compounds are of interest due to their potential applications in materials science.
• Understanding the synthesis and structural properties of novel vanadyl phosphates is crucial for developing new functional materials.

Purpose of the Study:

• To synthesize and characterize a new vanadyl oxalatophosphate, Na2[(VO)2(HPO4)2C2O4].2H2O.
• To determine the crystal structure and investigate the thermal decomposition behavior of the synthesized compound.

Main Methods:

• Hydrothermal synthesis was employed for the preparation of the compound.
• X-ray powder diffraction and solid-state Nuclear Magnetic Resonance (NMR) spectroscopy were used for structural determination and refinement.
• In situ temperature-dependent X-ray diffraction and thermogravimetry (TG) were utilized to study thermal decomposition.

Main Results:

• The compound Na2[(VO)2(HPO4)2C2O4].2H2O was successfully synthesized and crystallizes in the monoclinic space group P2(1).
• The crystal structure reveals infinite [(VO)(HPO4)] chains linked by oxalate groups, forming a 2D anionic layer with sodium ions and water molecules intercalated.
• Thermal decomposition occurs in three stages, involving water removal and oxalate group decomposition, ultimately yielding NaVOPO4.

Conclusions:

• The successful synthesis and structural elucidation of Na2[(VO)2(HPO4)2C2O4].2H2O provide new insights into the vanadyl phosphate system.
• The compound's layered structure and thermal decomposition pathway offer potential for further material development.
• The study highlights the utility of combining X-ray diffraction and solid-state NMR for comprehensive material characterization.