The results of quantum chemical calculations of isolated molecules of pentaammine-(5-cyano-2 H -tetrazolato- N ²)-, pentaammine-(5-nitrotetrazolato- N ²)-, tetraammine- cis -bis(5-nitro-2 H -tetrazolato- N ²)-, tetraammine- cis -bis(1-methyl-5-aminotetrazolo- N ³, N ⁴)cobalt(III) perchlorates and the products of their possible primary decomposition stage are presented. The energetics and pathways of such reactions are determined. For the first time, using quantum chemical calculations, it was shown that the decomposition of cobalt amminates can begin with the destruction of the tetrazole ligand and elimination of the nitrogen molecule, and not with the dissociation of the coordinated ammonia molecule from the inner sphere of the cobalt(III) complex. The activation and dissociation energies of these processes are determined.