What Is Manganese Sulfate?
Manganese sulfate is the sulfate of manganese.
There are two types of manganese sulfate, manganese sulfate(II) and manganese sulfate(III), depending on the oxidation number of manganese. Like most metal sulfates, manganese sulfate(II) can be anhydrous or hydrate, with 1, 4, 5, and 7 hydrates known.
Manganese sulfate(II) is nonflammable. However, it decomposes on heating, producing toxic gases containing sulfur oxides. Ingestion can affect the central nervous system and may cause hereditary diseases.
Uses of Manganese Sulfate
Manganese sulfate is widely used as a raw material for products in the industrial and agricultural fields.
In industry, it is used as a raw material for manganese metal and manganese compounds. It is used as a raw material for desiccants in paints or printing inks, as a rust inhibitor to prevent rusting of metals, and as a pigment for ceramics (a coloring agent for ceramic products).
In the agricultural field, manganese is one of the trace elements necessary for plant growth. Manganese sulfate is added to fertilizers to promote plant photosynthesis and aid in plant growth.
Properties of Manganese Sulfate
Manganese sulfate(II) has a light red color and is a crystalline or crystalline powder solid. It is soluble in water and virtually insoluble in ethanol. It is deliquescent, with a melting point of 700°C, and decomposes at 850°C.
Depending on the temperature, manganese sulfate(II) gives various hydrates: anhydrous when heated above 280°C; anhydrous is white and lumpy; below 9°C, 7-hydrate is formed; between 9 and 26°C, 5-hydrate is formed; between 26 and 27°C, orthorhombic 4-hydrate is formed; and above 27°C, 1-hydrate is formed. Common commercial products are tetrahydrate.
Oxidation of manganese sulfate(II) with potassium permanganate produces manganese dioxide, which is used in dry cell materials.
Structure of Manganese Sulfate
The chemical formula for manganese sulfate(II) is MnSO4. The molar mass is 151.001 g/mol for the anhydride, 169.02 g/mol for the monohydrate, and 223.07 g/mol for the tetrahydrate. The density is 3.25 g/cm3 for anhydride, 2.95 g/cm3 for monohydrate, and 2.107 g/cm3 for tetrahydrate. The crystal structure of anhydride is orthorhombic, while that of monohydrate and tetrahydrate are monoclinic.
Other Information on Manganese Sulfate
1. Natural Manganese Sulfate(II)
Manganese sulfate(II) is an important precursor to manganese metal and various manganese compounds. It occurs naturally as monohydrate in Szmikite, tetrahydrate in Ilesite, pentahydrate in Jokokuite, and septahydrate in Mallardite.
2. Synthesis of Manganese Sulfate(II)
When sulfuric acid reacts with manganese metal, hydrogen is generated and manganese Sulfate(II) is formed. Manganese ore is usually purified by treating it with sulfuric acid to produce an aqueous manganese sulfate solution.
Manganese sulfate(II) can also be synthesized from sulfuric acid and manganese hydroxide with water. In the laboratory, it can also be obtained by the reaction of sulfur dioxide and manganese dioxide.
Manganese sulfate(II) also occurs as a by-product of industrial processes such as the production of hydroquinone and anisaldehyde using manganese dioxide as the oxidizing agent.
3. Characteristics of Manganese Sulfate(III)
The chemical formula of manganese sulfate(III) is Mn2(SO4)3. It is a dark green powder with a molecular weight of 398.07 g/mol and a density of 3.24 g/cm3.
Manganese sulfate(III) can be obtained by dissolving manganese(IV) oxide monohydrate or potassium permanganate in concentrated sulfuric acid, or by heating Mn2(SO4)3･H2SO4･H2O. When dissolved in water, it becomes a red solution, and Mn(OH)3 is precipitated by hydrolysis.