Copper (Cu)

Copper is a chemical element with an atomic number of 29 in the periodic table of elements. The occurrence of this metal in Earth’s crust is about 0.25%, concentrated in copper ores. Apart from gold, copper is the only metal that does not naturally occur in gray or silver color. It also has two valence electrons that provide a relatively stable configuration. 

Chemical and Physical Properties of Copper

Atomic number29
Atomic weight (mass)63.546 g.mol-1
Group number11 (1b)
ColorA reddish-gold metal with an orange hue
Physical stateSolid at room temperature of 20°C
Half-lifeFrom 75 ns to 61.83 hours
Electronegativity according to Pauling1.9
Density8.96 g/cm³
Melting point1084.62°C, 1984.32°F, 1357.77 K
Boiling point2560°C, 4640°F, 2833 K
Ionic radius0.096 nm (+1) ; 0.069 nm (+3)
Most characteristic isotope63Cu
Electronic shell[Ar] 3d10 4s1
The energy of the first ionization743.5 kJ.mol -1
The energy of the second ionization1946 kJ.mol -1
UsesMost often used as an electrical conductor. Also used in the manufacture of water pipes. Its alloys are used in jewelry and for coins.
DescriptionBluish-silver, ductile metal.
Crystal StructureCubic: Face centered
Covalent Radius1.17 Å
Atomic Radius1.57 Å
Atomic Volume07.1 cm³/mol
Name OriginSymbol from Latin: cuprum (island of Cyprus famed for its copper mines).
Discovery dateKnown to the ancients.
Oxydation States(2),1

With the periodic table symbol Cu, atomic number 29, atomic mass of 63.546 g.mol-1, and electron configuration [Ar] 3d104s1, copper is both malleable and ductile metal with a face-centered cubic crystalline structure. Having excellent electrical and thermal conductivity, pure copper reaches its boiling point at 2560°C (4640°F, 2833 K), while the melting point is achieved at 1084.62°C (1984.32°F, 1357.77 K).

In addition, the corrosion-resistant copper metal has an electronegativity of 1.9 according to Pauling, whereas the atomic radius according to van der Waals is 0.128 nm. 

Copper can be polished to a bright lustrous finish, which places this element in the same group as silver and gold. The pure, elemental form of copper is softer than zinc and highly malleable. When copper forms a reaction with oxygen when exposed to high temperatures, it results in cuprous oxide (Cu2O).

Cryogenic Properties of Copper  

When exposed to temperatures below zero, copper and copper alloys display greater ductility and strength.

How Was Copper Discovered?

The first evidence of copper suggests that this reddish-gold metal with an orange hue was discovered by the ancient civilizations of Chaldea and Sumer. Chaldeans of Mesopotamia and Sumerians of the Tigris and Euphrates river valleys had used this non-precious metal 5,000 to 6,000 years ago.

Copper was the first metal to be smelted from sulfide ores. Ancient people also created art-objects by applying thin copper sheets on a wooden background with a bitumen lining. Such figures have been found in the archeological site at Tell al Ubaid

The Copper Age

The Chalcolithic Period, or the Copper Age, is a period that lasted for around 1000 years, from 500 B.C. to 3500 B.C. The period’s name is derived from the Greek words “chalco” (copper) and “lithos”(stone). Present-day northern Iraq holds the oldest copper ornament dating from around 8700 B.C.  

Right after the Copper Age, around 3500 BC, the ancient civilizations began making alloys of copper and tin in order to add hardness to the reddish-gold metal. In fact, the copper-tin alloy was used in construction around 3000 BC by the ancient civilizations. This period is referred to as the Bronze Age. 

How Did Copper Get Its Name?

This soft metal used since ancient times was presumably named after the main location from where the ancient people living in Mesopotamia, the Middle East, Egypt, Phoenicia, Greece, and Rome were obtaining copper – the Mediterranean island of Cyprus.

Namely, the ancient Romans have labeled the copper-producing ore as “aes Cyprium”, i.e “the metal of Cyprus” in Latin. Throughout the times, the name “cyprium” was modified by oral lore from “coprum”, into “cuprum”, to the present-day name of this chemical element – copper

Where Can You Find Copper?

The pure elemental form of copper, also labeled as “native copper”, can be found in ashes of seaweeds, sea corals, and the human liver. In nature, it’s obtained from various types of geological deposits and rocks, such as porphyry, sediment-hosted copper deposits, volcanic-hosted massive sulfide deposits, deposits of ultramafic, mafic, ultrabasic, and carbonatite rocks, veins in metamorphic rocks, as a primary mineral in basaltic lavas, etc. 

Also, copper can be obtained from oxidized ores (cuprite and tenorite), azurite, bornite, digenite, copper sulfosalts such as tetrahedrite-tennantite, and enargite, copper carbonates (azurite and malachite), and sulfide ores (chalcopyrite (CuFeS2), covellite (CuS), as well as from chalcocite (Cu2S)).  

Copper Mining Processes

The copper ores can be obtained via the following types of mining:

  • Surface open-pit mining (by blasting copper ore deposits);
  • Underground mining (by sinking a shaft to the ore);
  • Solution In-situ mining (drilling and using chemical solutions). 

After the extraction of the deposits, copper is isolated by high-temperature chemical reactions. Copper production also involves the following preparational procedures: 

  • Roasting;
  • Smelting;
  • Converting;
  • Fire refining.

The Largest Copper Deposits In the World

Peru and Chile’s Andean Mountains are the locations of the world’s largest known porphyric deposits formed by volcanic activity. Nowadays, Chile, Peru, Zaire, and Zambia are the leaders in the world’s copper market.

The United States takes fifth place on the copper market, right behind the aforementioned leading group of countries. The porphyry copper ore is mostly found in Arizona, New Mexico, Montana, and Utah – the countries that account for 99 percent of U.S. production of this soft metal. 

Copper in Everyday Life

Nowadays, copper is one of the metals with the largest application in everyday life. Copper sees a wide array of applications in everyday life since it’s found in a large number of alloys. Most commonly, copper has the following uses:

  • Making of coins and copper wire, electromagnets, lightning rods, switches, and  electrical relays;
  • In refrigerators and air conditioning systems;
  • Making of magnetrons, screws, and kettles;
  • Industrial machinery (such as heat exchangers);
  • In vacuum tubes and cathode-ray tubes;
  • For glass coloring and ceramic glaze;
  • Making of musical instruments (especially brass instruments, such as trumpet, trombone, flugel, horn);
  • Jewelry, ornaments, utensils, computer parts, household items, and weapons;
  • Nutritional supplements;
  • Water-proof roofing, building construction, and plumbing;
  • Artwork, high-value furniture, lamps, and decorative tea and coffee sets;
  • Production of brass (copper and zinc), bronze (copper and tin), and nickel silver (copper, zinc, and nickel) alloys;
  • Electric motors;
  • Manufacturing of electric vehicles (EVs), charging stations, inverters, and batteries;
  • Fungicides.

Copper as a Sustainable Energy Source

Copper is used in the production of sustainable energy, which benefits our environment immensely. Being one of the essential components of electric vehicles (EVs), solar photovoltaic panels, and building high-megawatt wind farms. As a result of the excellent electrical conductivity and heat, as well as its durability and malleable properties, copper is often the first-choice metal used in the manufacture of hybrid and electric buses. 

Electrical vehicles reduce environmental pollution and costs, thus supporting the economic growth of countries. The United States of America, in particular, are completely self-sufficient when it comes to copper. 

Copper in Medicine

Since ancient times, copper has been used as a medicine and purifier of drinking water. It’s one of the essential elements that contribute to balanced functions of the body and brain. 

Copper as a Trace Element

This chemical element is an indispensable trace element in the human body. It also plays a significant role in the normal growth and well-being of plants and animals. Copper deficiency may result in vitamin B12 and iron deficiency, fragile bones, neurological disorders, and anemia. 

Antimicrobial Properties of Copper

Copper naturally possesses some antibacterial properties. For this reason, the doorknobs, and handrails in public buildings are made of brass, bronze, or copper-nickel. According to the Copper Development Association, copper and copper alloys possess an inherent property of destroying harmful bacteria and have been included in the US Environmental Protection Agency’s Registered Public Health Claim as antimicrobial substances. 

Copper Supplements

Being naturally stored in bones and muscles, this mineral plays an important role in many of the body’s processes. When the copper levels are too low, copper deficiency occurs. The required quantity is supplemented via food rich in copper, by adding the synthesized form of this trace element in a form of tablets or intravenously (by IV).

Copper-Rich Foods

Some foods are naturally rich in copper. By including them in the daily diet, they can naturally regulate the required levels of the trace element in case of copper deficiency and enhance human health. The list includes:

  • Seafood (tuna, salmon, sardines, lobster);
  • Meat (pork, veal, beef, liver, turkey, chicken);
  • Egg yolk;
  • Dark chocolate;
  • Avocados;
  • Cashews;
  • Sesame seeds;
  • Mushrooms;
  • Sweet potatoes;
  • Pineapples;
  • Mangos;
  • Bananas;
  • Kiwifruit;
  • Apricots;
  • Jackfruit;
  • Dried Figs;
  • Prunes;
  • Turnip greens;
  • Beet greens;
  • Asparagus;
  • Soybean sprouts;
  • Artichokes;
  • Dates (Deglet Noor)
  • Dried cranberries;
  • Goat cheese.

Copper In the Modern Architecture

Copper has been given a valued place in the field of architecture as a substance suitable for the construction of many architectural elements, especially domes, wall claddings, spires, gutters, etc. At the same time, copper adds an artistic flair to the buildings.

The Statue of Liberty

Have you ever wondered what gives the Statue of Liberty its green color? It turns out that there are 179,000 pounds of copper used in the making of the Statue of Liberty. This metal has been used in the restoration of both the external and internal components of the Statue of Liberty. 

According to the research of the Copper Development Association, oxidation is the reason why copper turns greenish, rather than reddish-orange. Namely, the copper typically used for roofing always oxidizes into green verdigris (or patina).

Patina refers to a mixture of hydroxo-carbonate, hydroxo-sulfate, and small amounts of other compounds. Also, the weathering and oxidation had led to the reduction of the superficial copper layer to a thickness of only 0.005 inches (0.127 millimeters) in a century on one of the most famous monuments of New York. 

How Dangerous Is Copper?

The National Institute for Occupational Safety and Health (NIOSH) so far hasn’t classified copper as a carcinogen. However, long-term exposure to high levels of copper and its accumulation in the soft tissues may result in damage and dysfunction of the brain and the kidneys, liver problems, as well as some severe medical conditions, such as Wilson’s disease.

Wilson’s Disease

This genetic disorder occurs due to abnormal accumulations of copper in the body. Since copper participates in the building of nerves and bones as a trace element and supports the formation of melanin and collagen, excess amounts of this metal disturb these processes. 

Symptoms of a Prolonged Exposure to Copper

Even though copper is one of the trace elements found in the human body, the absorption of large quantities of this metal can lead to adverse health effects. Despite the fact that Wilson’s disease is a genetically inherited disorder and occurs in the first days of life, the symptoms do not appear until copper accumulates in the brain, liver, or any other soft tissue. The affected individuals may experience the following signs and symptoms:

  • Jaundice (characterized by a yellowish coloration of the skin and the white part of the eyes);
  • Kayser-Fleischer rings (a golden-brown discoloration of the eyes);
  • Legs or abdominal swelling as a result of liquids buildup;
  • Coordination problems,
  • Vomiting and diarrhea;
  • Severe headaches and dizziness;
  • Dysfunctional speech;
  • Rigidity of muscles;
  • Tiredness and lack of appetite.


If left untreated for a longer period of time, the following complications may occur:

  • Cirrhosis (scarring of the liver);
  • Dysfunctionality of the central nervous system;
  • Psychological problems.

Inheriting only one defective gene from both parents may result in Wilson’s genetically inherited disease. The carriers of this type of defective genes carry only one copy that does not provoke this disorder in them. However, they can transfer this gene onto the next generations. 

Environmental Effects of Copper

This substance can be found abundantly in the environment. It either occurs naturally in forest fires, sea spray, and decaying vegetation or can be traced near copper mines, industries using copper in their production, waste disposals, agricultural farms, or landfills. 

The water-soluble copper compounds impose the largest health hazard, since the contaminated water may affect food and drinking water. The dust particles spreading from the mining areas and the industrial plants may also contaminate the air. 

The Environmental Importance of Copper Recycling

Recycling copper has several significant environmental benefits, which include reduced energy requirements for the processing of this metal, solid waste diversion, as well as natural resource conservation. Old electrical cables and radiators, builders’ hardware, built-in appliances, wires, tubes, and brass goods make for great sources of scrap copper. 

Isotopes of Copper

This chemical element occurs in the form of two stable isotopes (63Cu and 65Cu), as well as 29 radioisotopes. Having a half-life of with a half-life of 61.83 hours, cuprum-67 is the most stable isotope of copper. While the stable isotopes of copper undergo a β− decay, the unstable isotopes decay by β+ decay. 



[n 1]

ZNIsotopic mass (Da)

[n 2][n 3]



[n 4]



[n 5]

Spin and


[n 6][n 7]

Natural abundance (mole fraction)
Excitation energy[n 7]Normal proportionRange of variation
52Cu292351.99718(28)# p51Ni(3+)#  
53Cu292452.98555(28)#<300 nsp52Ni(3/2−)#  
54Cu292553.97671(23)#<75 nsp53Ni(3+)#  
55Cu292654.96605(32)#40# ms [>200 ns]β+55Ni3/2−#  
56Cu292755.95856(15)#93(3) msβ+56Ni(4+)  
57Cu292856.949211(17)196.3(7) msβ+57Ni3/2−  
58Cu292957.9445385(17)3.204(7) sβ+58Ni1+  
59Cu293058.9394980(8)81.5(5) sβ+59Ni3/2−  
60Cu293159.9373650(18)23.7(4) minβ+60Ni2+  
61Cu293260.9334578(11)3.333(5) hβ+61Ni3/2−  
62Cu293361.932584(4)9.673(8) minβ+62Ni1+  
64Cu293563.9297642(6)12.700(2) hβ+ (61%)64Ni1+  
β (39%)64Zn
66Cu293765.9288688(7)5.120(14) minβ66Zn1+  
67Cu293866.9277303(13)61.83(12) hβ67Zn3/2−  
68Cu293967.9296109(17)31.1(15) sβ68Zn1+  
68mCu721.6(7) keV3.75(5) minIT (84%)68Cu(6-)  
β (16%)68Zn
69Cu294068.9294293(15)2.85(15) minβ69Zn3/2−  
69mCu2741.8(10) keV360(30) ns  (13/2+)  
70Cu294169.9323923(17)44.5(2) sβ70Zn(6-)  
70m1Cu101.1(3) keV33(2) sβ70Zn(3-)  
70m2Cu242.6(5) keV6.6(2) s  1+  
71Cu294270.9326768(16)19.4(14) sβ71Zn(3/2−)  
71mCu2756(10) keV271(13) ns  (19/2−)  
72Cu294371.9358203(15)6.6(1) sβ72Zn(1+)  
72mCu270(3) keV1.76(3) µs  (4-)  
73Cu294472.936675(4)4.2(3) sβ (>99.9%)73Zn(3/2−)  
β, n (<.1%)72Zn
74Cu294573.939875(7)1.594(10) sβ74Zn(1+, 3+)  
75Cu294674.94190(105)1.224(3) sβ (96.5%)75Zn(3/2−)#  
β, n (3.5%)74Zn
76Cu294775.945275(7)641(6) msβ (97%)76Zn(3, 5)  
β, n (3%)75Zn
76mCu0(200)# keV1.27(30) sβ76Zn(1, 3)  
77Cu294876.94785(43)#469(8) msβ77Zn3/2−#  
78Cu294977.95196(43)#342(11) msβ78Zn   
79Cu295078.95456(54)#188(25) msβ, n (55%)78Zn3/2−#  
β (45%)79Zn
80Cu295179.96087(64)#100# ms [>300 ns]β80Zn   

Source: Wikipedia

Copper Compounds 

The most common copper compounds occur as minerals, salts, acetates, oxides, chlorides, oxychlorides, and nitrates. 

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Turquoise is a copper(II) mineral. It got its name after the most significant country on its path to Europe. Namely, the French term “turquoise” denotes “Turkish”, due to the fact that this mineral was first mined in the historical Khorasan of Iran (Persia) before being brought to Europe through Turkey.

The color of this vividly blue (Persian blue) gemstone comes from the presence of copper in the turquoise producing ore. It can be found only in locations where the acidic, copper-rich groundwater forms chemical reactions with phosphorus and aluminum-containing minerals. 

The Role of Scheele’s Green (CuHAsO3) in Napoleon’s Death 

Scheele’s Green (CuHAsO3), or Schloss Green, is an acidic copper arsenite with a yellowish-green pigment that was extensively used in the past for the manufacturing of green paint. Despite its toxicity, it was also used as a coloring agent of some types of desserts.

Invented in 1775 by the Swedish pharmaceutical chemist Carl Wilhelm Scheele (1742 – 1786), it was commonly prepared as a solution of sodium carbonate and arsenious oxide that was added to a copper sulfate solution. 

Used for the coloring of wallpapers, in paints, and paintings, Sheele’s Green was also produced by the following copper compounds:

  • Copper metaarsenite (CuO·As2O3);
  • Copper arsenite salt (CuHAsO3, Cu(AsO3)2·3H2O);
  • Neutral copper ortho-arsenite (3CuO·As2O3·2H2O);
  • Copper arsenate (CuAsO2 and Cu(AsO2)2);
  • Copper di-arsenite (2CuO·As2O3·2H2O).

When the French statesman Napoleon Bonaparte was exiled to the South Atlantic island of St. Helena, he was accommodated in a green-walled room. The color of the walls is of great importance in this story because death found this distinguished military leader of the French Revolution in the aforementioned room – not on the battlefield.

Since he suffered from a  cancerous stomach ulcer, for many years after his death it was believed that this was the reason behind his demise. 

However, in the 1960s, scientists reopened this issue and discovered high amounts of arsenic in a sample of Bonaparte’s hair. The advanced means of research pointed to the green pigment of his room containing copper arsenic. 

The findings of the contemporary toxicological analysis of the hair sample also revealed that the humidity of the city where Napoleon Bonaparte resided contributed to an enhanced chemical reaction of the Scheele’s Green and oxygen in the air, leading to the release of arsenic. This helped explain the poisoning symptoms in the other members of the household. 

List of Copper Minerals

  • Agardite
  • Aktashite
  • Algodonite
  • Arcubisite
  • Arthurite
  • Anthonyite
  • Antipinite
  • Antlerite
  • Apachite
  • Arhbarite
  • Astrocyanite-(Ce)
  • Atacamite
  • Attikaite
  • Aubertite
  • Aurichalcite
  • Bayldonite
  • Bilibinskite
  • Boleite
  • Briartite
  • Bukovite
  • Blossite
  • Bluebellite
  • Botallackite
  • Brochantite
  • Calcio-volborthite
  • Caledonite
  • Chalcostibite
  • Chanabayaite
  • Cubanite
  • Cupalite
  • Calumetite
  • Carrollite
  • Cesbronite
  • Chalcanthite
  • Chalconatronite
  • Chalcophyllite
  • Chlorophyte
  • Chrysothallite
  • Clinoclase
  • Connellite
  • Cornetite
  • Cornubite
  • Cuprosklodowskite
  • Cyanotrichite
  • Demesmaekerite
  • Eilat stone
  • Enargite
  • Eskebornite
  • Euchlorine
  • Fingerite
  • Freibergite
  • Fukuchilite
  • Germanite
  • Hemusite
  • Icosahedrite
  • Iyoite
  • Kesterite
  • Khatyrkite
  • Kostovite
  • Lautite
  • Lemanskiite
  • Langite
  • Lavendulan
  • Leightonite
  • Libethenite
  • Linarite
  • Lindgrenite
  • Liroconite
  • Lyonsite
  • Mohite
  • Mooihoekite
  • Nekrasovite
  • Oosterboschite
  • Penroseite
  • Salzburgite
  • Schmiederite
  • Skaergaardite
  • Stannite
  • Tyrrellite
  • Tangeite
  • Teineite
  • Tenorite
  • Tlalocite
  • Tlapallite
  • Torbernite
  • Triazolite
  • Tsumebite
  • Turquoise
  • Tyrolite
  • Weissite
  • Wulffite
  • Zhanghengite

List of Copper Proteins

  • Amicyanin
  • Azurin
  • Hemocyanin
  • Keyhole limpet hemocyanin
  • Plastocyanin (a family of copper-binding proteins)
  • Rusticyanin
  • Stellacyanin

List of Copper(I) and Copper (II) Compounds and Salts

  • Bismuth strontium calcium copper oxide
  • Burgundy mixture
  • Calcium copper titanate
  • Chromated copper arsenate
  • Copper aspirinate
  • Copper benzoate
  • Copper chromite
  • Copper gluconate
  • Copper ibuprofenate
  • Copper monosulfide
  • Copper naphthenate
  • Copper peroxide
  • Copper usnate
  • Copper(II) acetate
  • Copper(II) arsenate
  • Copper(II) azide
  • Copper(II) bromide
  • Copper(II) carbonate
  • Copper hydride
  • Copper indium gallium selenide
  • Copper salicylate
  • Copper(I) acetylide
  • Copper(I) bromide
  • Copper(I) chloride
  • Copper(I) cyanide
  • Copper(I) fluoride
  • Copper(I) hydroxide
  • Copper(I) iodide
  • Copper(I) nitrate
  • Copper(I) oxide
  • Copper(I) phosphide
  • Copper(I) sulfate
  • Copper(I) sulfide
  • Copper(I) t-butoxide
  • Copper(I) thiocyanate
  • Copper(I) thiophene-2-carboxylate
  • Basic copper carbonate
  • Copper(II) chlorate
  • Copper(II) chloride
  • Copper(II) cyanurate
  • Copper(II) fluoride
  • Copper(II) hydroxide
  • Copper(II) nitrate
  • Copper(II) oxide
  • Copper(II) perchlorate
  • Copper(II) phosphate
  • Copper(II) selenite
  • Copper(II) sulfate
  • Copper(II) tetrafluoroborate
  • Copper(II) thiocyanate
  • Copper(II) triflate
  • Egyptian blue
  • Fehling’s solution
  • Han purple and Han blue
  • Paris green
  • Potassium tetrachlorocuprate(II)
  • Scheele’s Green
  • Thallium barium calcium copper oxide
  • Verdigris

5 Interesting Facts and Explanations

  1. Copper pots are a chef’s go-to cooking utensils because the food is evenly heated in them. 
  2. USS Constitution” or “Old Ironsides” is the oldest commissioned warship that is still afloat in Boston. Constructed in Boston in 1797, this legendary ship has a bronze cannon made by Paul Revere, one of the earliest American coppersmiths. 
  3. Chaldea is a country that existed somewhere between the late 10th and mid-6th centuries BC in the southeastern part of Mesopotamia. After the 6th century BC, the people of Chaldea were assimilated into Babylonia. 
  4. After iron and aluminum, copper comes in third on the list of the world’s most used metals. 
  5. A single Boeing 747-200 jet plane is made of about 9,000 pounds of copper.