Heptavalent manganese compound

Heptavalent manganese compound

Potassium permanganate KMnO _{4 is a} purple-black crystal, which is the most important Mn(Ⅶ) compound
.
The color of the aqueous solution is related to the concentration.

KMnO ₄ is the most important and most commonly used oxidant, which can be prepared by K ₂ MnO ₄ disproportionation, chlorination, electrolysis and other methods
.
However, the conversion rate of the disproportionation method is low, the cost of the chlorine oxidation method is high, and the electrolysis method is adopted in the industry

The oxidation ability and reduction products of KMnO ₄ differ significantly due to the acid-base degree of the medium
.
E.
g

In acidic solution KMn04 _.
4 is a strong oxidizing agent, capable of CI ^- , of Cr ³⁺ , the I ₂ and other oxidized with H ₂ O ₂ reaction solution was used to analyze the HO ₂ content

Laboratories often use the quantitative reaction between KMnO ₄ and H ₂ C ₂ O ₄ under acidic conditions to calibrate the concentration of KMnO ₄ solution
.

Permanganate is highly oxidative and thermodynamically unstable.
It decomposes significantly in acidic solutions and slowly decomposes in neutral or slightly alkaline solutions

The solid stability of permanganate is slightly higher, but it decomposes when the temperature is higher than 200℃
.

Other oxides of manganese are also formed at higher temperatures
.

KMnO ₄ is an important chemical raw material, used in the production of saccharin and benzoic acid , and can be used as a disinfectant and water purifier
.

KMnO ₄ reacts with cold concentrated sulfuric acid to produce dark green oily Mn ₂ O ₇
.

Mn ₂ O ₇ explodes when heated, and burns when it encounters organic matter
.

Light catalyzes the decomposition of potassium permanganate, so potassium permanganate solution should be stored in a brown bottle
.
Due to decomposition, its concentration will change with time.
The potassium permanganate standard solution needs to be re-calibrated before use