Self-propagating routes to transition-metal phosphides

Abstract

Frictional or thermal initiation (25–550 °C) of a mixture of sodium phosphide (Na₃P) and anhydrous transition-metal halides in evacuated sealed Pyrex or quartz ampoules produces transition-metal phosphides, sodium chloride and in some cases phosphorus via, an exothermic self-propagating reaction. The reaction proceeds with a short thermal flash (1–2s) with estimated reaction temperatures in excess of 1000 °C. The metal phosphides were purified by methanol trituration and characterised by X-ray powder diffraction, SEM, EDXA, magnetic moment measurements, FTIR, microanalysis and solid-state ³¹P NMR.