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 structu re and general formula CumMnCo2-(m+n)(OH)(3)NO3, (M = Ni, Zn) has been synt hesized by double jet precipitation technique, from the corresponding aqueo us metal nitrate solutions and NaOH. X-ray diffraction, infrared spectrosco py, and thermal analysis studies have shown that they are single phases whi ch decompose thermally at about 200 degrees C, yielding the corresponding s ingle-phase spinel-type oxides CuxMyCo3-(x+y)O4 (x = 3m/2,y = 3n/2). The ca tion distribution in these complex spinels has been calculated on the basis of the tetrahedral and octahedral M-O distances determined by X-ray Rietve ld refinement of their structures.