Plasma-assisted synthesis and properties of Na(3)N

Area of Science:

• Solid-state chemistry
• Inorganic materials synthesis
• Crystallography

Background:

• Sodium nitride (Na3N) is a rare compound with limited synthesis and characterization data.
• Understanding the structure and properties of alkali metal nitrides is crucial for materials science.

Purpose of the Study:

• To synthesize and characterize a novel sodium nitride compound.
• To determine the crystal structure and thermal stability of the synthesized sodium nitride.

Main Methods:

• Synthesis of sodium nitride (Na3N) via reaction of sodium or Na-K alloy with plasma-activated nitrogen at low pressure.
• Powder and single-crystal X-ray diffraction for structural determination.
• Differential scanning calorimetry to assess thermal decomposition.

Main Results:

• Dark-blue sodium nitride (Na3N) was successfully synthesized.
• The compound crystallizes in the cubic anti-ReO(3)-type structure (space group Pm3m, a = 4.73301(6) Å, Z = 1).
• Na3N decomposes into its elements above 104°C, with an estimated enthalpy of formation (ΔHf) of +64(2) kJ/mol.

Conclusions:

• A new cubic anti-ReO(3)-type sodium nitride (Na3N) has been synthesized and characterized.
• The compound exhibits limited thermal stability, decomposing at relatively low temperatures.
• This work provides fundamental data on alkali metal nitride structures and properties.