SYNTHESIS, CRYSTAL-STRUCTURE, AND PROPERT IES OF -HEXAAMINO-1-LAMBDA(5),3-LAMBDA(5)-DIPHOSPHAZENIUM CHLORIDE [(NH2)(3)PNP(NH2)(3)]CL

[(NH2)(3)PNP(NH2)(3)]Cl has been prepared by a three step synthesis. T he last step is the ammonolysis of [Cl3PNPCl3]Cl. Single crystals of 1 ,1,1,3,3,3-hexaamino-1 lambda(5), 3 lambda(5)-diphosphazenium chloride were obtained from an acetonitrile solution in a temperature gradient between 60 degrees C and room temperature. Between room temperature a nd -100 degrees C [(NH2)(3)PNP(NH2)(3)]Cl is subject to a phase transi tion. Therefore, the crystal structure was determined by single crysta l X-ray methods at room temperature (<(P)over bar 1>, a = 584.7(1) pm, b = 732.1(1) pm, c = 1092.0(2) pm, alpha = 71.05(3)degrees, beta = 76 .36(3)degrees, gamma = 89.83(3)degrees, Z = 2, R = 4.75%, wR = 2.47%). The cation [(NH2)(3)PNP(NH2)(3)](+) is built up by two corner sharing PN4 tetrahedra. Remarkably short P-N bonding distances have been obse rved and both PN4 tetrahedra exhibit a significant distortion resultin g in two large and four small N-P-N bond angles.