β-Li₂Zn₅: A Low Symmetric Polar Intermetallic Compound

Area of Science:

• Solid-state chemistry
• Crystallography
• Materials science

Background:

• Lithium-zinc (Li-Zn) compounds exhibit diverse crystal structures, often characterized by high symmetry and disorder.
• Understanding the structural variations in Li-Zn systems is crucial for developing new materials with tailored properties.

Purpose of the Study:

• To determine the crystal structure of the high-temperature modification of Li₂Zn₅.
• To identify the structural type and symmetry of β-Li₂Zn₅.
• To analyze the factors contributing to its lower symmetry compared to other Li-Zn compounds.

Main Methods:

• Single-crystal X-ray diffraction was employed to collect diffraction data.
• The crystal structure was solved and refined.
• Density Functional Theory (DFT) calculations were performed to analyze structural properties.

Main Results:

• β-Li₂Zn₅ represents a new binary structure type with triclinic space group P1̅.
• The unit cell parameters are a = 8.0073(3)Å, b = 11.5956(6)Å, c = 15.2956(5)Å, α = 96.39°, β = 101.92°, γ = 108.13°.
• The structure exhibits a pseudohexagonal motif with Li-zigzag and Zn chains, and displays high bond polarity with electron density transfer from Li to Zn atoms.

Conclusions:

• The determined crystal structure of β-Li₂Zn₅ provides a new structural model for Li-Zn binary compounds.
• The lower symmetry of β-Li₂Zn₅, compared to other Li-Zn compounds, is attributed to specific arrangements of Li and Zn atoms and verified by DFT calculations.
• The high polarity of bonds and electron transfer characteristics are key features of this compound.