Copper
Copper is a reddish-orange metal and one of the very few elements humans have used since prehistoric times, prized for millennia for its workability and, in the modern era, for being an outstanding conductor of electricity. It was one of the first metals people learned to shape, long before smelting or even the concept of chemical elements existed.
- Group · Period
- 11 · 4
- At room temp
- solid
- Melts at
- 1357.77 K
- Density
- 8.933 g/cm³
- Discovered
- Ancient
Uses
Copper’s excellent electrical conductivity makes it the backbone of modern electrical infrastructure, used extensively in wiring, motors, and electronics. It’s also a key material in plumbing, valued for its resistance to corrosion and its natural antimicrobial properties. Alloyed with other metals, copper forms bronze (with tin) and brass (with zinc), two alloys that have been essential to toolmaking, hardware, and decorative objects for thousands of years.
Copper’s natural resistance to bacteria and other microbes has also led to its use on frequently touched surfaces, like door handles and fixtures, in settings where reducing the spread of germs matters.
History
Copper has no single discoverer — it was one of the earliest metals worked by humans, going back roughly ten thousand years, because it occasionally occurs as pure native metal that early people could shape without smelting. As techniques for extracting it from ore developed, copper use became widespread enough that archaeologists mark a distinct Copper Age preceding the Bronze Age, when copper was alloyed with tin to make a harder metal. Its name, and its chemical symbol Cu, both trace back to “cuprum,” the Latin term referencing Cyprus, a major copper-producing region in the ancient world.
Fun facts
- Copper is one of the rare metals that can be found in nature as pure, native metal, which is part of why ancient humans worked with it so early.
- It's one of the best electrical conductors of any metal, second only to silver, which is why it's the standard choice for electrical wiring.
- Copper's chemical symbol, Cu, and its name both trace back to Cyprus, a major source of copper ore in the ancient Mediterranean world.
Frequently asked questions
Why is copper used for electrical wiring instead of a cheaper metal?
Copper conducts electricity with very little resistance, second only to silver among all metals, and it's far more affordable and easier to work with than silver at large scale. That combination of high conductivity, decent cost, and good ductility for drawing into wire is why it's remained the standard choice for household and industrial wiring for well over a century.
Who discovered copper?
No one person gets credit — copper was one of the first metals worked by prehistoric humans, discovered independently by different cultures thousands of years ago because it sometimes occurs as pure metal in nature and is relatively easy to shape. Its early adoption was significant enough that archaeologists use the term "Copper Age" for the period when it started replacing stone tools.
Why does copper turn green over time?
Exposed to air and moisture, copper slowly reacts to form a thin greenish coating called patina, made up of copper compounds like carbonates. Unlike iron rust, this layer is stable and actually protects the metal underneath from further corrosion, which is why old copper roofs and statues, like the Statue of Liberty, develop their well-known green color rather than deteriorating.
Compounds
6 notable compounds containing Cu
- Cu2Omineral
Copper(I) oxide
A red solid found in nature as the mineral cuprite, formed from copper's less common +1 oxidation state. It has long served as both a pigment and a protective coating additive.
Used for: Antifouling paint for ship hulls and red ceramic glaze pigment
- CuCl2salt
Copper(II) chloride
A yellow-brown solid (green when hydrated) well known for imparting a distinctive blue-green color to flames, a property used in flame tests and pyrotechnics alike.
Used for: Flame-coloring agent in pyrotechnics and catalyst in organic synthesis
- CuOoxide
Copper(II) oxide
A black solid representing copper's more common +2 oxidation state, formed readily when copper metal is heated in air and widely used to color glass and glazes.
Used for: Pigment in ceramics and glass; precursor in copper chemical manufacturing
- CuSO4salt
Copper(II) sulfate
Best known in its vivid blue pentahydrate form ("blue vitriol"), this is perhaps the most recognizable copper compound, prized for its striking color and long history in classic chemistry demonstrations.
Used for: Fungicide and algicide (Bordeaux mixture) and copper electroplating
- Cu2CO3(OH)2mineral
Malachite
A bright green basic copper carbonate mineral that forms naturally where copper ores weather, and is the same compound responsible for the green patina that develops on aged copper and bronze.
Used for: Ornamental stone and green pigment; ore of copper
- YBa2Cu3O7industrial
Yttrium barium copper oxide (YBCO)
A ceramic compound famous as the first material found to superconduct above the boiling point of liquid nitrogen, opening the door to more practical high-temperature superconductor research.
Used for: High-temperature superconductor in research and superconducting wires/tapes
Isotopes
31 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Cu-63 stable | 69.15% | Stable | — | -65,579.87 keV | 8,752.14 keV | — |
| Cu-65 stable | 30.85% | Stable | — | -67,263.68 keV | 8,757.1 keV | — |
Show all 31 isotopes
| Cu-53 | — | 130 ns | Proton emission | -13,140 keV | 7,891 keV | 3.51 × 10-9 eV |
| Cu-54 | — | 75 ns | Proton emission | -21,240 keV | 8,045 keV | 6.08 × 10-9 eV |
| Cu-55 | — | 55.9 ms | Electron capture / beta-plus decay (100%), ECP | -31,635.4 keV | 8,234 keV | 8.16 × 10-15 eV |
| Cu-56 | — | 80.4 ms | Electron capture / beta-plus decay (100%), ECP (0.4%) | -38,629.73 keV | 8,355.99 keV | 5.67 × 10-15 eV |
| Cu-57 | — | 196.3 ms | Electron capture / beta-plus decay (100%) | -47,309.01 keV | 8,503.26 keV | 2.32 × 10-15 eV |
| Cu-58 | — | 3.204 s | Electron capture / beta-plus decay (100%) | -51,667.85 keV | 8,570.97 keV | 1.42 × 10-16 eV |
| Cu-59 | — | 81.5 s | Electron capture / beta-plus decay (100%) | -56,358.45 keV | 8,642 keV | 5.60 × 10-18 eV |
| Cu-60 | — | 23.7 m | Electron capture / beta-plus decay (100%) | -58,345.26 keV | 8,665.6 keV | 3.21 × 10-19 eV |
| Cu-61 | — | 3.339 h | Electron capture / beta-plus decay (100%) | -61,984.06 keV | 8,715.51 keV | 3.80 × 10-20 eV |
| Cu-62 | — | 9.67 m | Electron capture / beta-plus decay (100%) | -62,787.54 keV | 8,718.08 keV | 7.86 × 10-19 eV |
| Cu-64 | — | 12.7006 h | Electron capture / beta-plus decay (61.5%), Beta-minus decay (38.5%) | -65,424.42 keV | 8,739.07 keV | 9.98 × 10-21 eV |
| Cu-66 | — | 5.120 m | Beta-minus decay (100%) | -66,258.29 keV | 8,731.47 keV | 1.49 × 10-18 eV |
| Cu-67 | — | 61.83 h | Beta-minus decay (100%) | -67,319.55 keV | 8,737.46 keV | 2.05 × 10-21 eV |
| Cu-68 | — | 30.9 s | Beta-minus decay (100%) | -65,567.04 keV | 8,701.89 keV | 1.48 × 10-17 eV |
| Cu-69 | — | 2.85 m | Beta-minus decay (100%) | -65,736.22 keV | 8,695.2 keV | 2.67 × 10-18 eV |
| Cu-70 | — | 44.5 s | Beta-minus decay (100%) | -62,976.38 keV | 8,646.87 keV | 1.03 × 10-17 eV |
| Cu-71 | — | 19.4 s | Beta-minus decay (100%) | -62,711.13 keV | 8,635.02 keV | 2.35 × 10-17 eV |
| Cu-72 | — | 6.63 s | Beta-minus decay (100%) | -59,783.01 keV | 8,586.53 keV | 6.88 × 10-17 eV |
| Cu-73 | — | 4.2 s | Beta-minus decay (100%), Beta-minus, neutron emission | -58,987.45 keV | 8,568.57 keV | 1.09 × 10-16 eV |
| Cu-74 | — | 1.63 s | Beta-minus decay (100%), Beta-minus, neutron emission (0%) | -56,006.21 keV | 8,521.56 keV | 2.80 × 10-16 eV |
| Cu-75 | — | 1.224 s | Beta-minus decay (100%), Beta-minus, neutron emission (3.5%) | -54,470.22 keV | 8,495.08 keV | 3.73 × 10-16 eV |
| Cu-76 | — | 0.641 s | Beta-minus decay (100%), Beta-minus, neutron emission (3%) | -50,981.63 keV | 8,443.6 keV | 7.12 × 10-16 eV |
| Cu-77 | — | 469.8 ms | Beta-minus decay (100%), Beta-minus, neutron emission (30.1%) | -48,862.83 keV | 8,411.25 keV | 9.71 × 10-16 eV |
| Cu-78 | — | 335 ms | Beta-minus decay (100%), Beta-minus, neutron emission (65%) | -44,789.47 keV | 8,354.67 keV | 1.36 × 10-15 eV |
| Cu-79 | — | 241.0 ms | Beta-minus decay (100%), Beta-minus, neutron emission (66%), B-2N | -42,408.04 keV | 8,320.94 keV | 1.89 × 10-15 eV |
| Cu-80 | — | 113.6 ms | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -36,679 keV | 8,246 keV | 4.02 × 10-15 eV |
| Cu-81 | — | 73.2 ms | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -31,910 keV | 8,185 keV | 6.23 × 10-15 eV |
| Cu-82 | — | 33 ms | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | -25,730 keV | 8,108 keV | 1.38 × 10-14 eV |
| Cu-83 | — | — | Beta-minus decay (100%), Beta-minus, neutron emission, B-2N | -20,390 keV | 8,044 keV | — |