Control of nonstoichiometric defects in manganese oxides by self-propagating high-temperature synthesis

Nonstoichiometric compounds of Mn1−δO were self-propagating high-temperature synthesized by ignition of thoroughly mixed powders of Mn, NaClO4, and MnO without additional external heating. The mixing ratio was systematically varied to control δ. Single phase Mn1−δO products containing nonstoichiometric defects were obtained for 0 < δ ≤ 0.025. With increase in δ, Mn3O4 content of the products is increased. Double phases of Mn1−δO and Mn3O4 were obtained at 0.025 < δ ≤ 0.150. The lattice parameter, a, of the single phase Mn1−δO was well explained by the linear equation: a = −0.0667δ + 4.448.