Potassium hypomanganate

Preparative routes

• by two-electron reduction of potassium permanganate with excess potassium sulfite;
• by the single-electron reduction of potassium manganate with hydrogen peroxide in 10 M potassium hydroxide solution;
• by the single-electron reduction of potassium manganate with mandelate in 3–10 M potassium hydroxide solution;
• by disproportionation when manganese dioxide is dissolved in a concentrated solution of potassium hydroxide;