A Novel High-Pressure Tin Oxynitride Sn₂ N₂ O

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Chemistry

Background:

• Oxynitrides are compounds containing oxygen and nitrogen.
• Previous studies focused on silicon and germanium oxynitrides.
• The coordination of metal atoms in oxynitrides influences their properties.

Purpose of the Study:

• To synthesize and characterize the first oxynitride of tin (Sn2N2O).
• To determine the crystal structure and physical properties of tin oxynitride.
• To compare the properties of tin oxynitride with related silicon and germanium compounds.

Main Methods:

• High-pressure synthesis at 20 GPa and 1200-1500°C.
• Characterization using synchrotron powder X-ray diffraction and automated diffraction tomography (ADT) in TEM.
• In-situ synchrotron X-ray diffraction in a diamond anvil cell to determine bulk modulus.
• Density Functional Theory (DFT) calculations for structural and electronic properties.

Main Results:

• Successfully synthesized tin oxynitride (Sn2N2O) with a Rh2S3-type crystal structure (space group Pbcn).
• Observed six-fold coordination for all tin atoms, distinct from four-fold coordination in Si and Ge analogs.
• Determined an isothermal bulk modulus (Bo) of 193(5) GPa.
• DFT calculations supported the structure model and provided insights into formation enthalpy, bulk modulus, and band structure.

Conclusions:

• The first oxynitride of tin, Sn2N2O, has been synthesized and characterized.
• Tin oxynitride exhibits a unique crystal structure with six-fold tin coordination.
• The high bulk modulus suggests potential applications in materials science.