MAGNESIUM AND CALCIUM NITRIDES AS NITROGEN-SOURCES IN METATHETICAL REACTIONS TO PRODUCE METAL NITRIDES

Reaction of Ca3N2 or Mg3N2 with anhydrous metal chlorides (MnCl2; MCl( 3), M = Ti, V, Mo, Nd, Sm, Gd, Tb, Er; MCl(3), M = Hf, W; MCl(5), M = Nb, Ta) in evacuated sealed Pyrex or quartz ampules at 500-900 degrees C or by filament initiation under nitrogen or argon was used to produ ce metal nitrides and calcium or magnesium chloride. The nitrides were purified by washing with methanol and isolated in ca. 70-90% yield. V ariation in reaction conditions allowed the isolation of intermediate phazes of Ln(2)Cl(3)N (Ln Sm, Gd, Tb, Er) and Ca2NCl, giving evidence that at least some of the reactions proceed via ionic metathesis pathw ays. Phase-pure VN and V2N were produced, both of which have previousl y been inaccessible in solid-state reactions using metathetical method s.