Zinc sulfate is the inorganic compound
with the formula ZnSO4 as well as any of
three hydrates. It was historically
known as "white vitriol". All of the
various forms are colorless solids. The
heptahydrate is commonly encountered. It
is on the World Health Organization's
List of Essential Medicines, a list of
the most important medication needed in
a basic health system.
Production and reactivity
Zinc sulfate is produced by treating
virtually any zinc containing material
with sulfuric acid.
Specific reactions the reaction of the
metal with aqueous sulfuric acid:
Zn + H2SO4 + 7 H2O → ZnSO4(H2O)7 + H2
Pharmaceutical grade zinc sulfate is
produced by treating high purity zinc
oxide with sulfuric acid:
ZnO + H2SO4 + 6 H2O → ZnSO4(H2O)7
In aqueous solution, all forms of zinc
sulfate behave identically. These
aqueous solutions consist of the metal
aquo complex [Zn(H2O)6]2+ and SO42−
ions. Barium sulfate forms when these
solutions are treated with solutions of
barium ions:
ZnSO4 + BaCl2 → BaSO4 + ZnCl2
With a reduction potential of -0.76,
zinc(II) reduces only with difficulty.
When heated over 680 C, zinc sulfate
decomposes into sulfur dioxide gas and
zinc oxide fume, both of which are
hazardous.
Applications
The hydrates, especially the
heptahydrate, are the primary forms used
commercially. The main application is as
a coagulant in the production of rayon.
It is also a precursor to the pigment
lithopone. Zinc sulfate is used to
supply zinc in animal feeds,
fertilizers, and agricultural sprays.
Zinc sulfate, like many zinc compounds,
can be used to control moss growth on
roofs. It is used as in electrolytes for
zinc plating, as a mordant in dyeing, as
a preservative for skins and leather and
in medicine as an astringent and emetic.
Minerals
As a mineral ZnSO4·7H2O is known as
goslarite. Zinc sulfate occurs as
several other minor minerals
Zinc-melanteriteSO4·7H2O. Lower hydrates
of zinc sulfate are rarely found in
nature:SO4·6H2O,SO4·4H2O, andSO4·H2O.
Safety
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.
References
^ Lide, David R., ed.. CRC Handbook of
Chemistry and Physics. Boca Raton, FL:
CRC Press. ISBN 0-8493-0487-3. 
^ a b Zumdahl, Steven S.. Chemical
Principles 6th Ed. Houghton Mifflin
Company. p. A23. ISBN 0-618-94690-X. 
^ a b c Dieter M. M. Rohe, Hans Uwe Wolf
"Zinc Compounds" in Ullmann's
Encyclopedia of Industrial Chemistry
2005, Wiley-VCH, Weinheim.
doi:10.1002/14356007.a28 537
^ "WHO Model List of
EssentialMedicines". World Health
Organization. October 2013. Retrieved 22
April 2014. 
^ "Zinc Sulphate Zinc Sulfate MSDS Sheet
of Manufacturers". Mubychem.com.
2013-05-05. Retrieved 2013-06-08. 
^ "Moss on Roofs," Community
Horticultural Fact Sheet #97, Washington
State University King County Extension,
[1]
^ European Food Safety Authority,
"Scientific Opinion on safety and
efficacy of zinc compounds as feed
additives for all animal species: Zinc
sulphate monohydrate", Feb 2012 [2]
