Crystalline Nitridophosphates by Ammonothermal Synthesis.

Nitridophosphates are a well-studied class of compounds with high structural diversity. However, their synthesis is quite challenging, particularly due to the limited thermal stability of starting materials like P3 N5 . Typically, it requires even high-pressure techniques (e.g. multianvil) in most cases. Herein, we establish the ammonothermal method as a versatile synthetic tool to access nitridophosphates with different degrees of condensation. α-Li10 P4 N10 , β-Li10 P4 N10 , Li18 P6 N16 , Ca2 PN3 , SrP8 N14 , and LiPN2 were synthesized in supercritical NH3 at temperatures and pressures up to 1070 K and 200 MPa employing ammonobasic conditions. The products were analyzed by powder X-ray diffraction, energy dispersive X-ray spectroscopy, and FTIR spectroscopy. Moreover, we established red phosphorus as a starting material for nitridophosphate synthesis instead of commonly used and not readily available precursors, such as P3 N5 . This opens a promising preparative access to the emerging compound class of nitridophosphates.