The courses of the ammonolyses of the ammonium hexafluorometalates of aluminum, gallium, and indium, (NH4)(3)MF6 (M = Al, Ga, In)

The courses of the ammonolysis reactions of the ammonium hexafluorometalate s (NH4)(3)MF6 (M = Al, Ga, In) were investigated with the aid of in-situ po wder diffractometry and differential thermal analysis. Under these conditio ns, the reaction of (NH4)(3)AlF6 With gaseous ammonia yields at about 360 d egrees C AlF3 via the intermediates NH4AlF4, Al(NH3)(2)F-3 and Al(NH3)F-3. The ammonolysis of (NH4)(3)GaF6 produces GaN at about 400 degrees C. Depend ing upon the actual reaction conditions, the intermediates NH4GaF4 and Ga(N H3)F-3 as well as their ammonia adducts NH4GaF4. NH3 and Ga(NH3)(2)F-3 and the amide-ammoniate Ga(NH3)(NH2)F-2 are observed. In the case of (NH4)(3)In F6 the intermediates (NH4)(3)InF6. NH3 and In(NH3)F-3 may exist; there are also indications for the reduction of In(III) to In(I) and for the existenc e of In(NH3)(2)F and InF as products of the ammonolysis of (NH4)(3)InF6.