It was noted that the diffusion of Na through the MnO2 lattice in a high-temperature solid-state reaction could affect the original structure of the oxide. This effect was significantly concentration-dependent. For x<0.5 in NaxMnO2, the chemical structure of the sodium manganese oxide was associated with the formation of MnO nanowires. The number of such nanowires increased upon increasing the concentration. At x > 0.5, it tended to form a conventional layered structure (with microscale particles). In the case of MnO2, this phenomenon occurred only for Na diffusion, when a chemical structure corresponding to Na0.44MnO2 formed.

Effect of Na Diffusion on the Formation of Fibrous Microcrystals of Manganese Oxide. A.Eftekhari, M.Kazemzad, F.Moztarzadeh: Materials Research Bulletin, 2005, 40[12], 2205-11