copper(II) sulfate

File:Synthesizing Copper Sulfate.jpg

Copper sulfate is produced industrially by treating copper metal with hot concentrated sulfuric acid or copper oxides with dilute sulfuric acid. For laboratory use, copper sulfate is usually purchased. Copper sulfate can also be produced by slowly leaching low-grade copper ore in air; bacteria may be used to hasten the process.{{cite web|title=Uses of Copper Compounds: Copper Sulphate|url=http://www.copper.org/resources/properties/compounds/copper_sulfate01.html|website=copper.org|publisher=Copper Development Association Inc.|access-date=10 May 2015}}

Commercial copper sulfate is usually about 98% pure copper sulfate, and may contain traces of water. Anhydrous copper sulfate is 39.81% copper and 60.19% sulfate by mass, and in its blue, hydrous form, it is 25.47% copper, 38.47% sulfate (12.82% sulfur) and 36.06% water by mass. Four types of crystal size are provided based on its usage: large crystals (10–40 mm), small crystals (2–10 mm), snow crystals (less than 2 mm), and windswept powder (less than 0.15 mm).

Copper(II) sulfate pentahydrate decomposes before melting. It loses two water molecules upon heating at {{cvt|63|C}}, followed by two more at {{cvt|109|C}} and the final water molecule at {{cvt|200|C}}.{{cite book |url=https://books.google.com/books?id=i9nyvTYBQtAC&pg=PA229 |pages=228–229 |title=Thermal decomposition of ionic solids |author=Andrew Knox Galwey |author2=Michael E. Green|publisher=Elsevier |year=1999 |isbn=978-0-444-82437-0}}{{cite book|url=https://books.google.com/books?id=LxhQPdMRfVIC&pg=PA1263|page=1263|title=Inorganic chemistry|first=Egon |last=Wiberg |author2=Nils Wiberg |author3=Arnold Frederick Holleman |publisher=Academic Press|year=2001|isbn=978-0-12-352651-9}}

The chemistry of aqueous copper sulfate is simply that of copper aquo complex, since the sulfate is not bound to copper in such solutions. Thus, such solutions react with concentrated hydrochloric acid to give tetrachlorocuprate(II):

:{{chem2|Cu(2+) + 4 Cl− → [CuCl4](2-)}}

Similarly treatment of such solutions with zinc gives metallic copper, as described by this simplified equation:{{cite journal |doi=10.15227/orgsyn.014.0066|title=P-Nitrophenyl Ether |journal=Organic Syntheses |year=1934 |volume=14 |page=66|author=Ray Q. Brewster, Theodore Groening }}

:{{chem2|CuSO4 + Zn → Cu + ZnSO4}}

A further illustration of such single metal replacement reactions occurs when a piece of iron is submerged in a solution of copper sulfate:

:{{chem2|Fe + CuSO4 → FeSO4 + Cu}}

In high school and general chemistry education, copper sulfate is used as an electrolyte for galvanic cells, usually as a cathode solution. For example, in a zinc/copper cell, copper ion in copper sulfate solution absorbs electron from zinc and forms metallic copper.{{cite book|last1=Zumdahl|first1=Steven|last2=DeCoste|first2=Donald|title=Chemical Principles|date=2013|publisher=Cengage Learning|isbn=978-1-285-13370-6|pages=506–507}}

:{{chem2|Cu(2+) + 2e− → Cu (cathode)}}, E^°_cell = 0.34 V

Copper sulfate is commonly included in teenage chemistry sets and undergraduate experiments.{{cite journal |doi=10.1021/ed079p486|title=A Copper-Sulfate-Based Inorganic Chemistry Laboratory for First-Year University Students That Teaches Basic Operations and Concepts |year=2002 |last1=Rodríguez |first1=Emilio |last2=Vicente |first2=Miguel Angel |journal=Journal of Chemical Education |volume=79 |issue=4 |page=486 |bibcode=2002JChEd..79..486R }} It is often used to grow crystals in schools and in Copper electroplating experiments despite its toxicity. Copper sulfate is often used to demonstrate an exothermic reaction, in which steel wool or magnesium ribbon is placed in an aqueous solution of {{chem2|CuSO4}}. It is used to demonstrate the principle of mineral hydration. The pentahydrate form, which is blue, is heated, turning the copper sulfate into the anhydrous form which is white, while the water that was present in the pentahydrate form evaporates. When water is then added to the anhydrous compound, it turns back into the pentahydrate form, regaining its blue color.{{cn|date=January 2025}} Copper(II) sulfate pentahydrate can easily be produced by crystallization from solution as copper(II) sulfate, which is hygroscopic.

Copper sulfate has been used for control of algae in lakes and related fresh waters subject to eutrophication. It "remains the most effective algicidal treatment".{{cite journal |doi=10.1051/jp4:20030547|title=Fate and forms of Cu in a reservoir ecosystem following copper sulfate treatment (Saint Germain les Belles, France) |year=2003 |last1=Van Hullebusch |first1=E. |last2=Chatenet |first2=P. |last3=Deluchat |first3=V. |last4=Chazal |first4=P. M. |last5=Froissard |first5=D. |last6=Lens |first6=P. N.L. |last7=Baudu |first7=M. |journal=Journal de Physique IV (Proceedings) |volume=107 |pages=1333–1336 }}{{cite journal |doi=10.1016/S0043-1354(00)00054-3|title=Forms and fate of Cu in a source drinking water reservoir following CuSO4 treatment |year=2000 |last1=Haughey |first1=M. |journal=Water Research |volume=34 |issue=13 |pages=3440–3452 }}

Bordeaux mixture, a suspension of copper(II) sulfate ({{chem2|CuSO4}}) and calcium hydroxide ({{chem2|Ca(OH)2}}), is used to control fungus on grapes, melons, and other berries.{{cite journal|title = Uses of Copper Compounds: Copper Sulfate's Role in Agriculture|journal = Annals of Applied Biology|volume = 20|issue = 2|pages = 342–363|doi=10.1111/j.1744-7348.1933.tb07770.x|year = 1933|last1 = Martin|first1 = Hubert}} It is produced by mixing a water solution of copper sulfate and a suspension of slaked lime.

A dilute solution of copper sulfate is used to treat aquarium fishes for parasitic infections,{{cite web|title = All About Copper Sulfate|publisher = National Fish Pharmaceuticals|url = http://www.nationalfishpharm.com/Q&A/all_about_copper.html|access-date = 2007-12-31}} and is also used to remove snails from aquariums and zebra mussels from water pipes.{{Cite web|date=2020-10-26|title=With Zebra mussels here to stay, Austin has a plan to avoid stinky drinking water|url=https://www.kxan.com/news/local/austin/with-zebra-mussels-here-to-stay-austin-has-a-plan-to-avoid-stinky-drinking-water/|access-date=2020-10-28|website=KXAN Austin|language=en-US}} Copper ions are highly toxic to fish. Most species of algae can be controlled with very low concentrations of copper sulfate.

Several chemical tests utilize copper sulfate. It is used in Fehling's solution and Benedict's solution to test for reducing sugars, which reduce the soluble blue copper(II) sulfate to insoluble red copper(I) oxide. Copper(II) sulfate is also used in the Biuret reagent to test for proteins.

Copper sulfate is used to test blood for anemia. The blood is dropped into a solution of copper sulfate of known specific gravity—blood with sufficient hemoglobin sinks rapidly due to its density, whereas blood which sinks slowly or not at all has an insufficient amount of hemoglobin.{{cite book|title = Basic Medical Laboratory Techniques|first= Barbara H. |last=Estridge |author2=Anna P. Reynolds |author3=Norma J. Walters |page = 166|publisher = Thomson Delmar Learning |year = 2000 |isbn = 978-0-7668-1206-2}} Clinically relevant, however, modern laboratories utilize automated blood analyzers for accurate quantitative hemoglobin determinations, as opposed to older qualitative means.{{citation needed|date=January 2023}}

In a flame test, the copper ions of copper sulfate emit a deep green light, a much deeper green than the flame test for barium.

Copper sulfate is employed at a limited level in organic synthesis.{{cite book|last=Hoffman |first=R. V. |title= Copper(II) Sulfate, in Encyclopedia of Reagents for Organic Synthesis|year= 2001|publisher= John Wiley & Sons|doi=10.1002/047084289X.rc247|chapter=Copper(II) Sulfate |isbn=978-0471936237 }} The anhydrous salt is used as a dehydrating agent for forming and manipulating acetal groups.{{cite book|author=Philip J. Kocienski| title=Protecting Groups|url=https://books.google.com/books?id=eI8p5B1uTJMC&pg=PA58| year=2005| publisher=Thieme| isbn=978-1-58890-376-1|page=58}} The hydrated salt can be intimately mingled with potassium permanganate to give an oxidant for the conversion of primary alcohols.{{OrgSynth|last = Jefford |first=C. W. |last2=Li |first2=Y. |last3=Wang |first3=Y.|prep = cv9p0462|title = A Selective, Heterogeneous Oxidation using a Mixture of Potassium Permanganate and Cupric Sulfate: (3aS,7aR)-Hexahydro-(3S,6R)-Dimethyl-2(3H)-Benzofuranone|collvol = 9|collvolpages = 462}}

Reaction with ammonium hydroxide yields tetraamminecopper(II) sulfate or Schweizer's reagent which was used to dissolve cellulose in the industrial production of Rayon.

Copper(II) sulfate has attracted many niche applications over the centuries. In industry copper sulfate has multiple applications. In printing it is an additive to book-binding pastes and glues to protect paper from insect bites; in building it is used as an additive to concrete to improve water resistance and prevent plant and mushroom growth. Copper sulfate can be used as a coloring ingredient in artworks, especially glasses and potteries.{{cite web|last1=Copper Development Association|title=Uses of Copper Compounds: Table A - Uses of Copper Sulphate|url=http://www.copper.org/resources/properties/compounds/table_a.html|website=copper|publisher=Copper Development Association Inc.|access-date=12 May 2015}} Copper sulfate is also used in firework manufacture as a blue coloring agent, but it is not safe to mix copper sulfate with chlorates when mixing firework powders.{{cite web|last1=Partin |first1=Lee |title=The Blues: Part 2 |url=http://www.skylighter.com/fireworks/how-to-make/blue-copper-fireworks-stars.asp |website=skylighter |publisher=Skylighter.Inc |access-date=12 May 2015 |url-status=dead |archive-url=https://web.archive.org/web/20101221162804/http://www.skylighter.com/fireworks/how-to-make/blue-copper-fireworks-stars.asp |archive-date=21 December 2010 }}

File:Copper sulfate etching bath.JPG

Copper sulfate was once used to kill bromeliads, which serve as mosquito breeding sites.{{cite book|last1=Despommier|last2=Gwadz|last3=Hotez|last4=Knirsch|title=Parasitic Disease|date=June 2005|publisher=Apple Tree Production L.L.C|location=NY|isbn=978-0970002778|pages=Section 4.2|edition=5|url=http://www.medicalecology.org/diseases/malaria/malaria.htm|access-date=12 May 2015}} Copper sulfate is used as a molluscicide to treat bilharzia in tropical countries.

In 2008, the artist Roger Hiorns filled an abandoned waterproofed council flat in London with 75,000 liters of copper(II) sulfate water solution. The solution was left to crystallize for several weeks before the flat was drained, leaving crystal-covered walls, floors and ceilings. The work is titled Seizure.{{cite web|url=https://www.artangel.org.uk/project/seizure/ |title=Seizure |publisher=Artangel.org.uk |access-date=2021-10-05}} Since 2011, it has been on exhibition at the Yorkshire Sculpture Park.{{cite web|url=http://www.ysp.co.uk/exhibitions/roger-hiorns-seizure|title=Roger Hiorns: Seizure|publisher=Yorkshire Sculpture Park|access-date=2015-02-22|archive-url=https://web.archive.org/web/20150222005608/http://www.ysp.co.uk/exhibitions/roger-hiorns-seizure|archive-date=2015-02-22|url-status=dead}}

Copper(II) sulfate is used to etch zinc, aluminium, or copper plates for intaglio printmaking.[http://www.greenart.info/galvetch/bordeaux.htm greenart.info], Bordeau etch, 2009-01-18, retrieved 2011-06-02.[http://www.ndiprintmaking.ca/?p=74 ndiprintmaking.ca], The Chemistry of using Copper Sulfate Mordant, 2009-04-12, retrieved 2011-06-02.

It is also used to etch designs into copper for jewelry, such as for Champlevé.[http://mordent.com/etch-howto/ http://mordent.com/etch-howto/], How to Electrolytically etch in copper, brass, steel, nickel silver or silver, retrieved 2015-05-2015.

Copper(II) sulfate can be used as a mordant in vegetable dyeing. It often highlights the green tints of the specific dyes.{{citation needed|date=December 2022}}

An aqueous solution of copper(II) sulfate is often used as the resistive element in liquid resistors.{{citation needed|date=December 2022}}

In electronic and microelectronic industry a bath of {{chem2|CuSO4*5H2O}} and sulfuric acid ({{chem2|H2SO4}}) is often used for electrodeposition of copper.{{Cite book |url=https://www.worldcat.org/oclc/868688018 |title=Copper Electrodeposition for Nanofabrication of Electronics Devices |date=2014 |author1=K. Kondo |author2=Rohan N. Akolkar |author3=Dale P. Barkey |author4=Masayuki Yokoi |isbn=978-1-4614-9176-7 |location=New York |oclc=868688018}}

Anhydrous copper(II) sulfate can be produced by dehydration of the commonly available pentahydrate copper sulfate. In nature, it is found as the very rare mineral known as chalcocyanite.{{Cite web|url=https://www.mindat.org/min-963.html|title=Chalcocyanite|website=www.mindat.org}} The pentahydrate also occurs in nature as chalcanthite. Other rare copper sulfate minerals include bonattite (trihydrate),{{Cite web|url=https://www.mindat.org/min-718.html|title=Bonattite|website=www.mindat.org}} boothite (heptahydrate),{{Cite web|url=https://www.mindat.org/min-720.html|title=Boothite|website=www.mindat.org}} and the monohydrate compound poitevinite.{{Cite web|url=https://www.mindat.org/min-3249.html|title=Poitevinite|website=www.mindat.org}}{{Cite web|url=https://www.ima-mineralogy.org/Minlist.htm|title=List of Minerals|date=March 21, 2011|website=www.ima-mineralogy.org}} There are numerous other, more complex, copper(II) sulfate minerals known, with environmentally important basic copper(II) sulfates like langite and posnjakite.{{Cite web|url=https://www.mindat.org/min-2322.html|title=Langite|website=www.mindat.org}}{{Cite web|url=https://www.mindat.org/min-3265.html|title=Posnjakite|website=www.mindat.org}}

{{Gallery

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| Anhydrous {{chem2|CuSO4}}

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| Copper(II) sulfate monohydrate

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| Copper(II) sulfate pentahydrate

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| The rare mineral boothite ({{chem2|CuSO4*7H2O}})

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{{See also|Copper toxicity}}

Copper(II) salts have an LD50 of 100 mg/kg.Windholz, M., ed. 1983. The Merck Index. Tenth edition. Rahway, NJ: Merck and Company.{{citation |publisher=U.S. Environmental Protection Agency, Office of Pesticide Programs |year=1986 |title=Guidance for reregistration of pesticide products containing copper sulfate. Fact sheet no. 100. |location=Washington, DC}}

Copper(II) sulfate was used in the past as an emetic.{{cite journal |last1=Holtzmann |first1=N. A. |last2=Haslam |first2=R. H. |title=Elevation of serum copper following copper sulfate as an emetic |journal=Pediatrics |volume=42 |issue=1 |pages=189–93 |date=July 1968 |doi=10.1542/peds.42.1.189 |pmid=4385403 |s2cid=32740524 }} It is now considered too toxic for this use.{{cite book |last=Olson |first=Kent C. |title=Poisoning & drug overdose |publisher=Lange Medical Mooks/McGraw-Hill |location=New York |year=2004 |page=[https://archive.org/details/poisoningdrugove00olso/page/175 175] |isbn=978-0-8385-8172-8 |url=https://archive.org/details/poisoningdrugove00olso/page/175 }} It is still listed as an antidote in the World Health Organization's Anatomical Therapeutic Chemical Classification System.{{ATC|V03|AB20}}

{{clear}}

• Chalcanthum
• Vitriol

{{reflist|30em}}

• {{cite book|ref =CRC92|editor=Haynes, William M.|year=2011|title=CRC Handbook of Chemistry and Physics (92nd ed.). |place=Boca Raton, FL |publisher=CRC Press|isbn=978-1439855119}}

• {{Commons category-inline}}
• {{ICSC|0751|07}}
• {{ICSC|1416|14}}
• [https://web.archive.org/web/20080302034606/http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory – Copper and compounds fact sheet]

{{Copper compounds}}

{{Sulfates}}

{{Antidotes}}

{{Sulfur compounds}}

{{Authority control}}

{{DEFAULTSORT:Copper(Ii) Sulfate}}

Category:Copper(II) compounds

Category:Sulfates

Category:Desiccants

Category:Herbicides