Physical and chemical properties of manganese dioxide MnO2

Manganese dioxide MnO2 overview

Manganese dioxide is an inorganic compound with the chemical formula MnO2. It is a black amorphous powder or black orthorhombic crystal. . For the preparation of manganese salts, also used as oxidant, rust remover, catalyst.

physical properties

Melting point: 535℃

Density: 5.03g/cm3

Appearance: black amorphous powder or black orthorhombic crystal

Water solubility: insoluble in water

chemical properties

Acidity and alkalinity: Manganese dioxide is an amphoteric oxide, which is a very stable black powdery solid at room temperature and can be used as a depolarizer for dry batteries. In the laboratory, its oxidizing property is often used, and it acts with concentrated HCl to produce chlorine gas.

Manganese dioxide is a strong oxidant in acidic media.

Manganese dioxide has an octahedral structure, the oxygen atoms are on the top of the octahedron, the manganese atom is in the octahedron, and the octahedrons are connected by common edges to form a single or double chain. These chains and other chains share the top to form a tunnel structure of voids. Octahedrons are either hexagonal close-packed, or cubic close-packed.

Manganese dioxide is an amphoteric oxide, and there are corresponding formal salts of perovskite structure such as BaMnO3 or SrMnO3 (obtained by a compound reaction in a molten alkali system), as well as manganese tetrachloride.

In the case of reducing agents, it is oxidizing. For example, manganese dioxide is heated to 1400K in a hydrogen stream to obtain manganese oxide; manganese dioxide is heated in an ammonia stream to obtain brown-black manganese trioxide; manganese dioxide is reacted with concentrated hydrochloric acid to obtain chloride Manganese, chlorine and water.

In the case of strong oxidants, it also exhibits reducing properties. If manganese dioxide, potassium carbonate and potassium nitrate or potassium chlorate are mixed and melted, a dark green melt can be obtained, and the melt can be dissolved in water and cooled to obtain potassium manganate, a compound of hexavalent manganese. It is a strong oxidant in acidic medium.

Strong oxidant, it does not burn by itself, but supports combustion, and should not be placed with flammable materials.

It is used as a catalyst in the reaction of potassium chlorate [KClO3] decomposition and hydrogen peroxide (hydrogen peroxide, H2O2) decomposition:

Application of manganese dioxide MnO2

Manganese dioxide MnO2 is used as a depolarizer for dry batteries, as a catalyst and oxidant in the synthesis industry, as a colorant, decolorizer, and iron removal agent in the glass industry and enamel industry. It is used in the manufacture of metal manganese, special alloys, ferromanganese castings, gas masks and ferrites for electronic materials. In addition, it can also be used in the rubber industry to increase the viscosity of rubber. It can also be used as a catalyst in chemical experiments.

Organic Synthesis Uses

Manganese dioxide is very useful in organic chemistry. Manganese dioxide is used in oxides in different forms, because manganese dioxide has multiple crystalline forms, the chemical formula can be written as MnO2 x(H2O)n, where x is between 0 and 0.5, and n can be greater than 0 . Manganese dioxide can be produced by the reaction of potassium permanganate (KMnO₄) and manganese sulfate (MnSO₄) at different pH.

One of the chemical reactions specific to manganese dioxide is the conversion of alcohols to aldehydes. Even if the alcohol has a double bond, it will not be oxidized by manganese dioxide: cis-RCH=CHCH2OH + MnO2 → cis-RCH=CHCHO + H2O + MnO

No matter how active the product is, it will not be oxidized again. Diols can be oxidized to dialdehydes by manganese dioxide. There are many other manganese dioxide reactions and can be used to oxidize amines, aromatics and triols.

laboratory use

It is used as a catalyst when hydrogen peroxide is decomposed to produce oxygen; it is used as a catalyst when potassium chlorate is decomposed by heating to produce oxygen; it can be aluminothermic reaction with elemental aluminum powder to obtain manganese. Used as pigment, yellow glass, etc.; react with hot concentrated hydrochloric acid to produce chlorine; react with molten caustic potash (potassium hydroxide) in the air to produce potassium manganate; in the decomposition reaction of potassium permanganate, manganese dioxide is used as a high Potassium manganate autocatalyst.

Manganese dioxide MnO2 price

The price of manganese dioxide MnO2 will change with random factors such as the production cost of manganese dioxide, transportation cost, international situation and the supply and demand of manganese dioxide MnO2 market. Tanki New Materials Co.,Ltd. aims to help industries and chemical wholesalers find high-quality, low-cost nanomaterials and chemicals by providing a full range of customized services. If you are looking for manganese dioxide MnO2, please feel free to send an inquiry to get the latest price of manganese dioxide.

Manganese dioxide MnO2 supplier

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