SYNTHESIS, CRYSTAL-STRUCTURE, AND PROPERT IES OF TETRAAMINOPHOSPHONIUM CHLORIDE [P(NH2)(4)]CL

[P(NH2)(4)]Cl has been prepared by ammonolysis of phosphorus pentachlo ride in liquid ammonia. The product was purified by reacting the bypro duct, ammonium chloride. with diethylamine and removing the diethylami ne hydrochloride. Suitable single crystals were obtained from an aceto nitrile solution in a temperature gradient between 60 degrees C and ro om temperature. The crystal structure of [P(NH2)(4)]Cl has been determ ined by single crystal X-ray methods (Pbcn, a = 470.8(2), b = 1622.3(3 ), c = 756.3(2) pm, Z = 4). In the solid, [P(NH2)(4)](+) and Cl- ions are found, resembling a TlI-analogous structure. The N-H ... Cl distan ces indicate N-H ... Cl hydrogen bonding interactions. The distortion of the P-N sceleton of the cation and the very short P-NH2 distances ( mean value: 161.2 pm) have been confirmed by ab initio calculations, w hich show a generalized anomeric effect of the electron pairs at nitro gen and p pi d pi bonding.