Potassium dimanganate(III), K6Mn2O6, is a manganese(III) compound.

Unlike lithium and sodium manganites, MMnO2, which are best described as mixed oxides, potassium dimanganite contains discrete Mn2O6−6 anions in the solid state.

[2] It rapidly hydrolyzes in air.

[1] K6Mn2O6 is prepared as ruby-red crystals by the reaction of excess potassium oxide with manganese(II) oxide in a sealed nickel bomb at 610 °C for ten days.

[1] The Mn2O6−6 anion has an Al2Cl6-type structure.