Nickelatetrazoles have been proposed as intermediates in the course of the
photoreaction of Ni-II complexes of [NiP2(N-3)(2)] constitution (P-2: mono-
or diphosphane ligands). However, any metallatetrazoles as well as their o
rganic analogue, 5H-carbatetrazole, could neither be prepared nor identifie
d up to now. Based on density functional theory (DFT) calculations, predict
ions are given concerning the molecular and electronic structure of tetrazo
les. While 5H-tetrazole is indeed a rather unstable species, metallatetrazo
le moieties in square-planar d(8) transition metal complexes should be expe
rimentally accessible.