Quantum-chemical modeling of the structure, electronic properties, and stability of hexagonal manganese clusters (MnAkBi)m · nH2O (A, B = O, SO4, H2SO4; i, k = 0, 1, 2; n = 3–15, m = 3, 6, 12) has been performed by the density functional theory method with gradient correction (PBE and B3LYP). It has been demonstrated that the hexagonal manganese clusters can react with water to release oxygen and ozone (upon the transition to low-lying excited states, for example, on heating or exposure to light). The release of ozone from the (MnO2)n clusters (n = 3, 6, 12, …) requires the smallest energy input. It has been revealed that the interaction with hydrogen in the gas phase can lead to the adsorption of ozone onto the cluster surface.