Synthesis and thermal stability study of cobalt hydroxynitrate in different polytypic modifications

Cobalt hydroxysalt exists in Co(OH)(NO3), Co2(OH)3(NO3), Co3(OH)4(NO3)2 and Co7(OH)12(NO3)2 compositions. Co2(OH)3(NO3) has been prepared by varying the experimental conditions. The X-ray powder diffraction patterns of Co2(OH)3(NO3) obtained by different methods exhibit significant changes in their peak positions and the relative intensities. Careful analysis of the X-ray powder diffraction patterns of Co2(OH)3(NO3) samples reveals that it can crystallize in different polytypic modifications. The thermal decomposition studies show that the Co2(OH)3(NO3) of 3R2 polytype has better structural stability compared to Co2(OH)3(NO3) of 1H polytype.