First ternary tungsten tellurate(IV) WTe₂O₇ with unique crystal structure type

Area of Science:

• Solid-state chemistry
• Materials science
• Crystallography

Background:

• Ternary tungsten tellurates represent an underexplored class of inorganic compounds.
• Understanding the synthesis and structure of novel materials under extreme conditions is crucial for materials discovery.

Purpose of the Study:

• To synthesize and characterize a novel ternary tungsten tellurate compound.
• To determine the crystal structure and electronic properties of the new material.
• To investigate the presence and influence of lone pair electrons on tellurium atoms.

Main Methods:

• High-pressure/high-temperature synthesis using a multianvil apparatus.
• Single-crystal X-ray diffraction for crystal structure determination.
• X-ray photoelectron spectroscopy (XPS) for oxidation state verification.
• Density Functional Theory (DFT) calculations for electronic structure and vibrational spectra.

Main Results:

• Successful synthesis of the first ternary tungsten tellurate, WTe₂O₇, at 10 GPa and 1273 K.
• Determination of a novel triclinic crystal structure (space group P1̄) with edge-linked [WO₆] octahedra and four-coordinated Te⁴⁺.
• XPS confirmed W⁶⁺ and Te⁴⁺ oxidation states.
• DFT calculations revealed residual electron density on Te⁴⁺, indicative of lone electron pairs.

Conclusions:

• The novel ternary tungsten tellurate WTe₂O₇ has been successfully synthesized and structurally characterized.
• The crystal structure is defined by [WO₆] octahedra and Te⁴⁺ atoms with significant lone pair character.
• DFT calculations support the structural findings and highlight the electronic properties related to lone pairs.