Mn4+ vacancies in hexagonal birnessite, both reduce the band gap, and therefore enhance electrical conductivity. Half-metallic behavior was observed for MnO2 nanosheets with Mn vacancies, rendering them promising candidates for applications in spintronics. Birnessite is able to break down prions via oxidation. How well this process works outside the laboratory is unclear. See also Other manganese oxides: Buserite Pyrolusite Psilomelane References Sodium minerals Calcium minerals Potassium minerals Manganese(III,IV) minerals Hydroxide minerals Monoclinic minerals Minerals in space group 12