In Situ Single-phase Formation of LaCl(CN₂) Mixed-Anion Compound Via Controlled Pyrolysis of La³⁺ Modified Melamine...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Solid-State Chemistry

Background:

• Mixed-anion compounds containing nitride (N^3-) or cyanamide (CN₂^2-) offer unique properties.
• Synthesis of these materials, especially those incorporating N^3- or CN₂^2-, presents significant challenges.

Purpose of the Study:

• To demonstrate the in situ single-phase formation of a LaCl(CN₂) mixed-anion compound.
• To develop a safe and stable single-source precursor method for synthesizing cyanamide-based materials.

Main Methods:

• Chemical modification of melamine with LaCl₃ to create a precursor complex.
• Controlled heating and pyrolysis under a nitrogen atmosphere.
• Characterization using density functional theory, UV-vis spectroscopy, and X-ray photoelectron spectroscopy.

Main Results:

• Successful in situ single-phase formation of LaCl(CN₂) from a melamine-LaCl₃ precursor.
• Formation of an intermediate LaCl(CN₂)/g-C₃N₄ composite followed by decomposition of g-C₃N₄ at higher temperatures.
• Electronic properties determined: band gap energy (4.7 eV), valence band maximum (1.8 eV), and conduction band minimum (-2.9 eV relative to Fermi energy).

Conclusions:

• This study presents a novel and safe method for synthesizing LaCl(CN₂) using a single-source precursor.
• The developed approach facilitates the exploration and potential application of various cyanamide-based mixed-anion compounds.