Compounds containing urea-precursors of mixed oxides. I - Synthesis of nickel ferrite

A polynuclear coordination compound precursor of nickel ferrite, correspond ing to the molecular formula, [Fe2Ni(urea)(6)](NO3)(8). 2H(2)O was synthesi zed using two methods, respectively, a solid state method and a coprecipita tion one. The polynuclear compound was characterized by elemental analysis, vibrational and electronic spectral measurements and thermal analysis. Aft er a thermal treatment (4 hours at 800 degrees C) of the calcination residu es, a clean, well-crystallized nickel ferrite with particle size 350 Angstr om was obtained.