[en] The specific features revealed in the structure of the molybdenum and tungsten peroxo complexes with the ratios M: O₂ = 1: 1, 1: 2, and 1: 4 are considered. It is demonstrated that the geometry of the coordination polyhedron of the metal atom is primarily determined by the 'metal: peroxo ligand' ratio. Formally, the pentagonal bipyramidal coordination polyhedra of the Mo(VI) and W(VI) oxo monoperoxo and oxo diperoxo complexes (the coordination numbers of the metal atoms are equal to seven) have different geometries, namely, the MO(O₂)A₄ pseudooctahedral and MO(O₂)₂A₂ pseudotrigonal bipyramidal configurations