Phosphorus Nitride P₃N₅:  Synthesis, Spectroscopic, and Electron Microscopic Investigations

Pure, stoichiometric, hydrogen-free, and crystalline phosphorus nitride P 3 N 5 has been obtained for the first time by reaction of (PNCl 2 ) 3 and NH 4 Cl between 770 and 1050 K. The compound has been characterized by elemental analyses, 31 P and 15 N MAS NMR, EXAFS, IR spectroscopy, X-ray powder diffraction, and electron microscopy. In the solid a three-dimensional cross-linked network structure of corner sharing PN 4 tetrahedra has been identified with 2 / 5 of the nitrogen atoms bonded to three P atoms and 3 / 5 of the nitrogen atoms bonded to two P atoms. By electron diffraction (ED) and high-resolution transmission electron microscopy (HRTEM) two distinguishable modifications α-P 3 N 5 and β-P 3 N 5 have been identified which differentiate only by the stacking order of identical sheets similar to the polytypes of SiC.