Zinc sulfate is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

. It is used as a

dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...

to treat zinc deficiency and to prevent the condition in those at high risk. Side effects of excess supplementation may include abdominal pain, vomiting,

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

, and

tiredness Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

. The most common form includes water of crystallization as the heptahydrate, with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

. It was historically known as "white vitriol". Zinc sulfate and its hydrates are colourless solids.

Uses

Medicine

In medicine it is used together with oral rehydration therapy (ORT) and an astringent.

Manufacturing

The hydrates, especially the heptahydrate, are the primary forms used commercially. The main application is as a coagulant in the production of

rayon Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose f ...

. It is also a precursor to the pigment lithopone. It is also used as an

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...

for zinc

electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be ...

, as a mordant in dyeing, and as a preservative for skins and leather.

Other

Zinc sulfate is used to supply zinc in animal feeds, fertilizers, toothpaste, and agricultural sprays. Zinc sulfate, like many zinc compounds, can be used to control moss growth on roofs. Zinc sulfate can be used to supplement zinc in the brewing process. Zinc is a necessary nutrient for optimal yeast health and performance, although it is not a necessary supplement for low-gravity beers, as the grains commonly used in brewing already provide adequate zinc. It is a more common practice when pushing yeast to their limit by increasing alcohol content beyond their comfort zone. Before modern stainless steel, brew Kettles, fermenting vessels and after wood, zinc was slowly leached by the use of copper kettles. A modern copper immersion chiller is speculated to provide trace elements of zinc; thus care must be taken when adding supplemental zinc so as not to cause excess. Side effects include "...increased acetaldehyde and fusel alcohol production due to high yeast growth when zinc concentrations exceed 5 ppm. Excess zinc can also cause soapy or goaty flavors." Zinc sulfate is a potent inhibitor of

sweetness Sweetness is a Taste#Basic tastes, basic taste most commonly Perception, perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasure, pleasurable. In addition to sugars like sucrose, many other chemical compounds ...

perception for most sweet-tasting substances.

Toxicity

Zinc sulfate powder is an eye irritant. Ingestion of trace amounts is considered safe, and zinc sulfate is added to animal feed as a source of essential zinc, at rates of up to several hundred milligrams per kilogram of feed. Excess ingestion results in acute stomach distress, with nausea and vomiting appearing at 2–8 mg/kg of body weight.

Production and reactivity

Zinc sulfate is produced by treating virtually any zinc-containing material (metal, minerals, oxides) with sulfuric acid. Specific reactions include the reaction of the metal with aqueous

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

: : Pharmaceutical-grade zinc sulfate is produced by treating high-purity zinc oxide with sulfuric acid: : In aqueous solution, all forms of zinc sulfate behave identically. These aqueous solutions consist of the metal aquo complex and ions.

Barium sulfate Barium sulfate (or sulphate) is the inorganic compound with the chemical formula Ba SO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium an ...

forms when these solutions are treated with solutions of barium ions: : With a reduction potential of −0.76 V, zinc(II) reduces only with difficulty. When heated above 680 °C, zinc sulfate decomposes into

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...

gas and zinc oxide fume, both of which are hazardous.

Minerals

As a mineral, ZnSO₄•7H₂O is known as goslarite. Zinc sulfate occurs as several other minor minerals, such as

zincmelanterite Zincmelanterite is a mineral, a sulfate of zinc, copper and iron with the chemical formula . It is a soft monoclinic yellow green mineral with Mohs hardness of 2 and a specific gravity of 2.02. It was discovered in 1920 in the Vulcan mining distr ...

, (structurally different from goslarite). Lower hydrates of zinc sulfate are rarely found in nature: (bianchite), (boyleite), and ( gunningite).

References

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