Crystalline Nitridophosphates by Ammonothermal Synthesis.

Area of Science:

• Solid-state chemistry
• Materials science
• Inorganic synthesis

Background:

• Nitridophosphates exhibit high structural diversity but are challenging to synthesize.
• Limited thermal stability of precursors like phosphorus pentanitride (P3N5) necessitates harsh conditions, including high pressures.
• Existing synthetic routes often rely on precursors that are not readily available.

Purpose of the Study:

• To establish the ammonothermal method as a versatile synthetic route for nitridophosphates.
• To explore the use of red phosphorus as a viable starting material.
• To synthesize nitridophosphates with varying degrees of condensation.

Main Methods:

• Ammonothermal synthesis in supercritical ammonia (NH3) under ammonobasic conditions.
• Utilizing red phosphorus as a precursor instead of P3N5.
• Employing temperatures up to 1070 K and pressures up to 200 MPa.
• Product characterization via powder X-ray diffraction, energy dispersive X-ray spectroscopy, and FTIR spectroscopy.

Main Results:

• Successful synthesis of diverse nitridophosphates including α-Li10P4N10, β-Li10P4N10, Li18P6N16, Ca2PN3, SrP8N14, and LiPN2.
• Demonstrated the efficacy of the ammonothermal method for nitridophosphate synthesis.
• Established red phosphorus as a practical and accessible starting material.

Conclusions:

• The ammonothermal method is a versatile and effective tool for synthesizing nitridophosphates.
• The use of red phosphorus offers a promising and accessible route to this emerging class of compounds.
• This work expands the synthetic accessibility of structurally diverse nitridophosphates.