Thermal decomposition of potassium permanganate

Smoldering splint flares up.

Scientific name: Potassium permanganate decomposes under heating.


Make Potassium manganate K2MnO4 (Thermal decomposition of KMnO4)

by ChemExperimentalist

Synthesis of K2MnO4 (Decomposition Of KMnO4)

by AHW214


Wear eye protection goggles and gloves. Reaction products are toxic. Avoid contact with produced substances.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

2KMnO4 → K2MnO4 + MnO2 + O2

Step-by-step instruction

  1. Put about 1 gram of potassium permanganate in the test-tube.
  2. Clamp it on the stand.
  3. Heat the test tube with a gas burner.
  4. Hold the smoldering splint to the mouth of the test tube.
  5. The splint flares up.

Scientific background

In the laboratory oxygen is produced by thermal or catalytic decomposition of oxygen contained substances. Heating potassium permanganate gives potassium manganate, magnesium oxide and oxygen. Since oxygen supports burning, splinter flashing is a common test on the presence of oxygen.


Published on 05 May 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst