Phosphorus nitride P3N5: Synthesis, spectroscopic, and electron microscopic investigations

Pure, stoichiometric, hydrogen-free, and crystalline phosphorus nitride P3N5 has been obtained for the first time by reaction df(PNCl2)(3) and NH4Cl between 770 and 1050 K. The compound has been characterized by elemental analyses, P-31 and N-15 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 PN4 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 alpha-P3N5 and beta-P3N5 have been identified which differentiate only by the stacking order of identical sheets similar to the polytypes of SiC.