Synthesis and cation distribution of the spinel cobaltites CuxMyCo3-(x+y)O4 (M = Ni, Zn) obtained by pyrolysis of layered hydroxide nitrate solid solutions

A series of hydroxide nitrate solid solutions with a simple layered structure and general formula CumMnCo2-(m+n)(OH)(3)NO3, (M = Ni, Zn) has been synthesized by double jet precipitation technique, from the corresponding aqueous metal nitrate solutions and NaOH. X-ray diffraction, infrared spectroscopy, and thermal analysis studies have shown that they are single phases which decompose thermally at about 200 degrees C, yielding the corresponding single-phase spinel-type oxides CuxMyCo3-(x+y)O4 (x = 3m/2,y = 3n/2). The cation distribution in these complex spinels has been calculated on the basis of the tetrahedral and octahedral M-O distances determined by X-ray Rietveld refinement of their structures.