Sulfate of manganese (II) or manganese sulfate is an inorganic s alt of sulfuric acid and manganese, which has an oxidation state of 2+. It is also sometimes called manganese sulfate. The chemical formula of manganese sulfate is MnSO4. In nature, it occurs as crystalline hydrates in some minerals: smikite (monohydrate), ilesite (tetrahydrate), jococuite (pentahydrate), mallardite (heptahydrate).
Receive
This s alt is obtained by dissolving manganese (II) oxide or manganese carbonate in sulfuric acid.
MnO + H2SO4=MnSO4 + H 2O
MnCO3 + H2SO4=MnSO4 + H2O + CO2
Manganese oxide is a fairly common raw material, so almost all manganese sulfate is obtained in this way.
It can be obtained by leaching reduced ore with ammonium sulfate. It is also a by-product of the processing of manganese carbonate ores.
Physical properties
Manganese sulfate is a colorless crystalline powder. Its solutions have a slightly pink tint due to the formation of an aquacomplex with manganese [Mn(H2O)6]2+ . Easily soluble in water, very slightly in alcohols and ethylene glycol. The maximum solubility is reached at 25 °C. Melting point - 700 °C, at 850 °C it decomposes into oxides of sulfur and manganese. The density of crystals at 20 °C is 3.25g/cm3. It is a paramagnet, i.e. magnetized in an external magnetic field.
Can absorb water to form crystalline hydrates with 1, 4, 5 or 7 water molecules. These crystalline hydrates are pink in color and have slightly different physical properties from anhydrous manganese sulfate. Each of them has its own temperature range in which it will be most stable: monohydrate - only above 200 °C, tetrahydrate - at 30-40 °C, pentahydrate - 9-25 °C, heptahydrate - only below 9 °C. Almost all of these crystalline hydrates erode in air (lose water and break down), except for the tetrahydrate.
Chemical properties
Since the manganese in this s alt has the lowest oxidation state (+2), this s alt can be a reducing agent and interact with strong oxidizing agents:
2MnSO4 + 8HNO3 + 5PbO2=2HMnO 4 + 4Pb(NO3)2 + Pb(HSO4) 2 + 2H2O
Reacts with alkalis, with precipitation:
MnSO4 + 2KOH=Mn(OH)2↓ + K2SO4
Metal manganese can be obtained by electrolysis of a solution of manganese sulfate:
2MnSO4 + 2H2O=2Mn↓ + O2 + 2H 2SO4
Application
In chemical production, this s alt is used to obtain pure manganese and its other compounds. It is also used as an analytical reagent. In the food industry and pharmaceuticals, it is a dietary supplement (for both humans and animals). It is also a catalyst in organic synthesis. Detailed technical data on this substance are available in various GOSTs. Manganese sulfate is used in the textile industry as a component of dyes for fabrics and porcelain.
The main use of manganese sulfate is fertilizer. Manganese and sulfur are important elements for plant growth, and in this compound they are in a very accessible form for them, because manganese sulfate is highly soluble in water.
More about the use of fertilizer
This fertilizer can be applied to almost all plants and on any soil. Sandy and forest soils definitely need the use of this fertilizer. Carefully it is worth increasing the concentration of manganese on chernozems in order to prevent an overabundance of this element. This can lead to intoxication of plants and the appearance of spots on the edges of the leaves. But it should be borne in mind that soil acidity affects the rate of s alt dissolution: inin acidic soils, manganese sulfate dissolves more slowly, which means it is more slowly absorbed by plants. Therefore, before applying fertilizer, it is desirable to deoxidize the soil with limestone.
Manganese vitriol qualitatively and quantitatively increases crop yields, as manganese helps to increase the chlorophyll content in plants. With its deficiency, chlorosis, fusarium, brown spotting and brown rust occur: young leaves become too small and spots appear on them, and old ones become pale and yellow between the veins. Such leaves quickly die off, which is why the plants are delayed in growth and flowering. Some crops stop fruiting altogether.
Usually, manganese sulfate is applied together with nitrogen, phosphorus and potash fertilizers. It increases the ability of plants to absorb other essential nutrients: potassium, nitrogen and phosphorus. It also increases the sugar content in crops. This is especially true of root crops, berries and vegetables. Juices that are obtained from such fruits have a low acidity. All this has a positive effect on the shelf life of fruits.
This fertilizer has another useful property: it is not washed out by precipitation, thereby remaining in the soil for a long time. This makes the effect of the fertilizer prolonged. When used in greenhouse conditions, it is recommended to apply fertilizer in the form of a solution with a concentration not higher than 0.2%. It is best to water fertilized plants with water at a temperature of 20-25 ° C, since s alt dissolves bestexactly in this interval.
Safety
Manganese sulphate is a toxic substance. Moreover, both anhydrous and its crystalline hydrates. When ingested, it causes severe poisoning, which can seriously damage the nervous and digestive systems, as well as the brain. When it comes into contact with the skin, dermatitis and eczema appear, which are very difficult to treat.
When working with this substance, it is necessary to cover exposed skin, be sure to wear rubber gloves and a respirator. The room must be well ventilated or have a ventilation system, as well as constantly checked for the maximum permissible concentration of manganese in the air. Manganese sulfate should be stored only in sealed packaging.
