SYNTHESIS, CRYSTAL-STRUCTURE, AND PROPERT IES OF PHOSPHORUS(V) NITRIDE IMIDE HP4N7

Pure HP4N7 was obtained as a fine crystalline solid which is resistant to hydrolysis. The compound was synthesized by thermal condensation a t 750 degrees C in sealed quartz ampoules starting from the molecular precursor compound (NH2)(2)P(S)NP(NH2)(3). The crystal structure was s olved by direct methods and refined by a Rietveld algorithm on the bas is of synchrotron X-ray powder diffraction data which have been collec ted at the NSLS Brookhaven, beamline X7A (HP4N7, P2(1)/a, a = 1507.95( 2), b = 480.304(6), c = 710.722(8)pm, beta = 92.191(1)degrees, Z = 4, 1689 reflections, WRp = 0.082, R-p = 0.063, R-F = 0.038). In HP4N7 the re are PN4-tetrahedra as characteristic structural motifs which are co nnected through common edges and corners resulting in a three-dimensio nal network structure. Two out of seven nitrogen each are bridging two and the remaining N are bridging three neighbouring P atoms. Solid st ate IR spectroscopy of HP4N7 reveals a strong N-H stretching vibration at 3089 cm(-1). The P-31 MAS NMR spectrum shows one signal at -26 ppm . In a nonoxidizing atmosphere HP4N7 is Stable up to 800 degrees C. Ab ove that temperature NH3 eliminates and P3N5 is formed.