Combining MN Octahedra and PN Trigonal Bipyramids in the Mica-like Nitridophosphates MP N (M=Al, In).

Layered silicates are a very versatile class of materials with high importance to humanity. The new nitridophosphates MP N (M=Al, In), synthesized from MCl , P N and NH N in a high-pressure high-temperature reaction at 1100 °C and 8 GPa, show a mica-like layer setup and feature rare nitrogen coordination motifs. The crystal structure of AlP N was elucidated from synchrotron single-crystal diffraction data (space group Cm (no. 8), a=4.9354(10), b=8.1608(16), c=9.0401(18) Å, β=98.63(3)°), enabling Rietveld refinement of isotypic InP N . It is built up from layers of PN tetrahedra, PN trigonal bipyramids and MN octahedra. PN trigonal bipyramids have been reported only once and MN octahedra are sparsely found in the literature. AlP N was further characterized by energy-dispersive X-ray (EDX), IR and NMR spectroscopy. Despite the vast amount of known layered silicates, there is no isostructural compound to MP N as yet.