Nonstoichiometric compounds of Mn1-delta O 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 delta. Single phase Mn1-delta O products containing nonstoichiometric defects were obtained for 0 < delta <= 0.025. With increase in delta, Mn3O4 content of the products is increased. Double phases of Mn1-delta O and Mn3O4 were obtained at 0.025 < delta <= 0.150. The lattice parameter, a, of the single phase Mn1-delta O was well explained by the linear equation: a = -0.06675+4.448. (C) 2012 Elsevier B.V. All rights reserved.