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About Copper

Copper Bohr

Copper is a soft, ductile, and highly conductive metal that has been used by human societies since antiquity. Gold and meteoric iron were the only metals in common use prior to copper’s discovery circa 9000 BCE. This early use was facilitated by the existence of native copper deposits, which could be worked cold due to the softness of the metal. However, native copper is not particularly common, and eventually the process smelting of copper from ore was developed, which in turn led to the accidental discovery of alloying.

Adding another metal to copper increases its hardness and makes it easier to cast, making the metal considerably more useful. This occurred initially through the smelting of copper ores that contained small amounts of other metals, often arsenic and silicon, to produce a natural bronze. Later, it was discovered that bronze could be produced intentionally by adding tin to copper melt. This advance occurred between 4500 BCE and 600 BCE in different regions of the world. Bronze production is now recognized to be such a key technological achievement that the period in any society between this discovery and the development of iron smelting is often referred to as the “Bronze Age”.

The introduction of bronze allowed for the protection of harder, more durable metal tools and weapons. Bronze was so essential to civilizations of this period that history was shaped by the trade of the relatively rare tin ore necessary for its production. Though copper was easier to come by, its sources were also significant to ancient societies, and in fact lead to the naming of the element. In the Roman empire, copper was most often mined on the island of Cyprus, and the modern name of the metal is derived from the latin cuprum, which itself was derived from cyprium, meaning “metal of Cyprus”.

Though for many uses, alloys have preferable properties to pure copper metal, architecture has made use of elemental copper since ancient times. The patina that the metal develops over time provides a natural coating that makes it extremely durable and low-maintenance, and its malleability lends it to being molded into desired shapes. Today, copper in architecture is most often seen in roofing, flashings, rain gutters, and downspouts.

Metals other than tin came into use for alloying with copper later in history, especially nickel and zinc. Brass, an alloy of zinc and copper, is more malleable than either individual meta, easier to cast and has excellent acoustic properties. Initially, brass was used in coins and for decorative purposes, while today it is used extensively in brass musical instruments, for plumbing and electrical applications, and in applications such as lock where low metal-on-metal friction is required. Cupronickel alloys, including ancient Chinese paktong and european nickel silver or German silver, were initially used in a variety of applications, and still find use in the production of coins, plumbing fixtures, and musical instruments. Copper is also found in some gold alloys and in sterling silver.

In addition to using copper and its alloys widely for tools, instruments, currency, and building materials, ancient societies took advantage of copper for its antimicrobial properties. Though the ancient Egyptians did not understand that the copper was preventing the growth of microscopic organisms, they did recognized that water stored in copper vessels went foul less frequently, and that wounds dressed with copper tended to heal better. Today copper is still used in this capacity in a variety of settings, most notably hospitals, where coatings of copper on frequently-touched surfaces helps to limit the spread of disease-causing organisms.

Current applications for copper make frequent use of one of its properties that was not of particular interest for most of our history: electrical conductivity. Copper can be easily drawn into wires, and is the preferred electrical conductor for most wiring applications--roughly half of all copper mined is used in this way. In addition to being highly conductive, copper has high tensile strength, low thermal expansion, and resists corrosion and creep, properties which together result in reliable circuitry. The high conductivity of copper also enhances the energy efficiency of electric motors. Copper is likewise found in electronic devices such as electromagnets, vacuum tubes, magnetrons, and microwaves. Heat sinks and heat exchangers in electronic devices also sometimes use copper, as it dissipates heat more quickly than the most common alternative, aluminum.

Copper compounds also have many notable uses. Copper oxides and carbonates are used in pigments and glassmaking, and copper sulfate can be used as an herbicide, fungicide, and pesticide, as well as a chemical reagent in organic synthesis. Several copper compounds are semiconductors, including copper (I) oxide, one of the materials in which many semiconductor applications were first investigated. Today, copper semiconductors mostly find use in thin film solar cells. Copper can also be a component of high-temperature superconductors, and copper is used frequently in organic synthesis as a catalyst.

Naturally-occurring metallic copper has at times played a significant role in commercial supply of the metal, but most copper is found in sulfide, carbonate, and oxide minerals. Copper sulfides are the major copper ore, and after separation from iron and other unwanted material, these are roasted to produce the oxide. Copper oxide is then converted to blister copper through heating, and further purified through electrorefining. Copper is also recyclable without any loss in quality, and is the third most recycled metal after iron and aluminum.

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Sputtering Targets

High Purity (99.999%) Copper Oxide (CuO) Powder Copper is used as a building material, a conductor of heat and electricity, and as a component of various metal alloys. Due to its high electrical conductivity, large amounts of copper are used by the electrical industry for wire. Since copper is resistant to corrosion caused by moisture, it is widely used in pipes, coins, and jewelry. Copper too soft to be used alone in most applications, so it is instead incorporated in numerous alloys. For example, brass is a copper-zinc alloy, and bronze is a copper-tin alloy. Copper sulfate (CuSO4· H2O), also known as blue vitrol, is the most well-known copper compound. It is used as an agricultural poison, an algicide, and as a pigment for inks. Cuprous chloride (CuCl) is a powder used to absorb carbon dioxide (CO2). Copper cyanide (CuCN) is often used in electroplating applications. High Purity (99.9999%) Copper (Cu) Sputtering TargetCopper is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Copper nanoparticles and nanopowders are also available. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Copper is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Copper Properties

Copper(Cu) atomic and molecular weight, atomic number and elemental symbolCopper is a Block D, Group 11, Period 4 element. The number of electrons in each of copper's shells is 2, 8, 18, 1 and its electron configuration is [Ar] 3d10 4s1. Elemental CopperCopper Bohr ModelThe copper atom has a radius of 127.8 .pm and its Van der Waals radius is In its elemental form, CAS 7440-50-8, copper has a red-orange metallic luster appearance. Of all pure metals, only silver has a higher electrical conductivity. Copper was first discovered by Early Man. The origin of the word copper comes from the Latin word 'cuprium' which translates as "metal of Cyprus". Cyprus, a Mediterranean island, was known as an ancient source of mined copper.

Symbol: Cu
Atomic Number: 29
Atomic Weight: 63.546
Element Category: transition metal
Group, Period, Block: 11, 4, d
Color: orange-red
Other Names: Cuprum, Cuivre, Kupfer, Cobre
Melting Point: 1083.0 °C, 1981.4 °F, 1356.15 K
Boiling Point: 2567.0 °C, 4652.6 °F, 2840.15 K
Density: 8.96 g/cm3
Liquid Density @ Melting Point: 8.02 g·cm3
Density @ 20°C: 8.96 g/cm3
Density of Solid: 8920 kg·m3
Specific Heat: 0.092 Cal/g/K @ 25°C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 13
Heat of Vaporization (kJ·mol-1): 306.7
Heat of Atomization (kJ·mol-1): 337.15
Thermal Conductivity: 401 W·m-1·K-1
Thermal Expansion: (25 °C) 16.5 µm·m-1·K-1
Electrical Resistivity: 1.678 µΩ·cm @ 20°C
Tensile Strength: N/A
Molar Heat Capacity: 24.440 J·mol-1·K-1
Young's Modulus: 110–128 GPa
Shear Modulus: 48 GPa
Bulk Modulus: 140 GPa
Poisson Ratio: 0.34
Mohs Hardness: 3
Vickers Hardness: 369 MPa
Brinell Hardness: 35 HB = 874 MPa
Speed of Sound: (r.t.) (annealed) 3810 m·s,-1
Pauling Electronegativity: 1.9
Sanderson Electronegativity: 1.98
Allred Rochow Electronegativity: 1.75
Mulliken-Jaffe Electronegativity: 1.49 (s orbital)
Allen Electronegativity: N/A
Pauling Electropositivity: 2.1
Reflectivity (%): 90
Refractive Index: N/A
Electrons: 29
Protons: 29
Neutrons: 35
Electron Configuration: [Ar] 3d10 4s1
Atomic Radius: 128 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 132±4 pm
Covalent Radius (Å): 1.22
Van der Waals Radius: 140 pm
Oxidation States: +1, +2, +3, +4 (mildly basic oxide)
Phase: Solid
Crystal Structure: Cubic
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) 119.117
1st Ionization Energy: 745.49 kJ·mol-1
2nd Ionization Energy: 1957.93 kJ·mol-1
3rd Ionization Energy: 3554.64 kJ·mol-1
CAS Number: 7440-50-8
EC Number: 231-159-6
MDL Number: MFCD00010965
Beilstein Number: N/A
SMILES Identifier: [Cu]
InChI Identifier: InChI=1S/Cu
PubChem CID: 23978
ChemSpider ID: 22414
Earth - Total: 31 ppm
Mercury - Total: 5.1 ppm
Venus - Total: 35 ppm
Earth - Seawater (Oceans), ppb by weight: 3
Earth - Seawater (Oceans), ppb by atoms: 0.29
Earth -  Crust (Crustal Rocks), ppb by weight: 68000
Earth -  Crust (Crustal Rocks), ppb by atoms: 22000
Sun - Total, ppb by weight: 700
Sun - Total, ppb by atoms: 10
Stream, ppb by weight: 6
Stream, ppb by atoms: 0.09
Meterorite (Carbonaceous), ppb by weight: 110000
Meterorite (Carbonaceous), ppb by atoms: 31000
Typical Human Body, ppb by weight: 1000
Typical Human Body, ppb by atom: 99
Universe, ppb by weight: 60
Universe, ppb by atom: 1
Discovered By: N/A
Discovery Date: Around 9000 BC
First Isolation: N/A

Health, Safety & Transportation Information for Copper

Copper is an essential trace element in animals and plants, but in excess copper is toxic. Safety data for Copper and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Copper.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228-H400
Hazard Codes F
Risk Codes 11
Safety Precautions 16
RTECS Number GL5325000
Transport Information UN 3089 4.1/PG 2
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)
Flame-Flammables Environment-Hazardous to the aquatic environment

Copper Isotopes

Copper has two stable isotopes, 63Cu and 65Cu.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
52Cu 51.99718(28)# N/A p to 51Ni (3+)# N/A 390.35 -
53Cu 52.98555(28)# <300 ns p to 52Ni (3/2-)# N/A 409.61 -
54Cu 53.97671(23)# <75 ns p to 53Ni (3+)# N/A 426.07 -
55Cu 54.96605(32)# 40# ms [>200 ns] β+ to 55Ni; p to 54Ni 3/2-# N/A 443.46 -
56Cu 55.95856(15)# 93(3) ms β+ to 56Ni (4+) N/A 459 -
57Cu 56.949211(17) 196.3(7) ms β+ to 57Ni 3/2- N/A 475.46 -
58Cu 57.9445385(17) 3.204(7) s β+ to 58Ni 1+ N/A 488.2 -
59Cu 58.9394980(8) 81.5(5) s EC to 59Ni 3/2- N/A 500.93 -
60Cu 59.9373650(18) 23.7(4) min EC to 60Ni 2+ 1.219 510.88 -
61Cu 60.9334578(11) 3.333(5) h EC to 61Ni 3/2- 2.14 522.68 -
62Cu 61.932584(4) 9.673(8) min EC to 62Ni 1+ -0.38 531.69 -
63Cu 62.9295975(6) STABLE - 3/2- 2.2233 542.56 69.17
64Cu 63.9297642(6) 12.700(2) h EC to 64Ni; β- to 64Zn 1+ -0.217 550.64 -
65Cu 64.9277895(7) STABLE - 3/2- 2.3817 560.59 30.83
66Cu 65.9288688(7) 5.120(14) min β- to 66Zn 1+ -0.282 567.73 -
67Cu 66.9277303(13) 61.83(12) h β- to 67Zn 3/2- N/A 576.74 -
68Cu 67.9296109(17) 31.1(15) s β- to 68Zn 1+ N/A 582.96 -
69Cu 68.9294293(15) 2.85(15) min β- to 69Zn 3/2- N/A 591.04 -
70Cu 69.9323923(17) 44.5(2) s β- to 70Zn (6-) N/A 596.32 -
71Cu 70.9326768(16) 19.4(14) s β- to 71Zn (3/2-) N/A 604.4 -
72Cu 71.9358203(15) 6.6(1) s β- to 72Zn (1+) N/A 609.68 -
73Cu 72.936675(4) 4.2(3) s β- to 73Zn; β- + n to 72Zn (3/2-) N/A 616.83 -
74Cu 73.939875(7) 1.594(10) s β- to 74Zn (1+,3+) N/A 622.11 -
75Cu 74.94190(105) 1.224(3) s β- to 75Zn; β- + n to 74Zn (3/2-)# N/A 628.33 -
76Cu 75.945275(7) 641(6) ms β- to 76Zn; β- + n to 75Zn (3,5) N/A 632.68 -
77Cu 76.94785(43)# 469(8) ms β- to 77Zn 3/2-# N/A 638.9 -
78Cu 77.95196(43)# 342(11) ms β- to 78Zn N/A N/A 643.25 -
79Cu 78.95456(54)# 188(25) ms β- + n to 78Zn; β- to 79Zn 3/2-# N/A 648.53 -
80Cu 79.96087(64)# 100# ms [>300 ns] β- to 80Zn N/A N/A 651.02 -
Copper Elemental Symbol

Recent Research & Development for Copper

  • The Environmental Legacy of Copper Metallurgy and Mongol Silver Smelting Recorded in Yunnan Lake Sediments. Aubrey L. Hillman, Mark B. Abbott, JunQing Yu, Daniel J. Bain, and TzeHuey Chiou-Peng. Environ. Sci. Technol.: February 16, 2015
  • Highly dispersed copper oxide clusters as active species in copper-ceria catalyst for preferential oxidation of carbon monoxide. Wei-Wei Wang, Pei-Pei Du, Shi-Hui Zou, Huan-Yu He, Rui-Xing Wang, Zhao Jin, Shuo Shi, Yuying Huang, Rui Si, Qi-Sheng Song, Chun-Jiang Jia, and Chun-Hua Yan. ACS Catal.: February 13, 2015
  • NO Decomposition Activated by Preadsorption of O2 onto Copper Cluster Anions. Shinichi Hirabayashi and Masahiko Ichihashi. J. Phys. Chem. C: February 12, 2015
  • Synthesis of Vinyl Trifluoromethyl Thioethers via Copper-Mediated Trifluoromethylthiolation of Vinyl Bromides. Yangjie Huang, Jianping Ding, Chuyi Wu, Huidong Zheng, and Zhiqiang Weng. J. Org. Chem.: 42047
  • Renal Clearance and Degradation of Glutathione-coated Copper Nanoparticles. Jie Zheng, Shengyang Yang, Shasha Sun, Chen Zhou, Guiyang Hao, Jinbin Liu, Saleh Ramezani, Mengxiao Yu, and Xiankai Sun. Bioconjugate Chem.: February 12, 2015
  • Copper-Catalyzed N-Cyanation of Sulfoximines by AIBN. Fan Teng, Jin-Tao Yu, Zhou Zhou, Haoke Chu, and Jiang Cheng. J. Org. Chem.: 42045
  • Aggregation, dissolution and transformation of copper nanoparticles in natural waters. Jon Robert Conway, Adeyemi S. Adeleye, Jorge L Gardea-Torresdey, and Arturo A. Keller. Environ. Sci. Technol.: February 9, 2015
  • Lewis Acid-Induced Change from Four- to Two-Electron Reduction of Dioxygen Catalyzed by Copper Complexes Using Scandium Triflate. Saya Kakuda, Clarence Rolle, Kei Ohkubo, Maxime A. Siegler, Kenneth D. Karlin, and Shunichi Fukuzumi. J. Am. Chem. Soc.: February 7, 2015
  • Tris(2,2'-azobispyridine) Complexes of Copper(II): X-ray Structures, Reactivities, and the Radical Nonradical Bis(ligand) Analogues. Suvendu Maity, Suman Kundu, Thomas Weyhermüller, and Prasanta Ghosh. Inorg. Chem.: February 4, 2015
  • Proton Conduction and Long-Range Ferrimagnetic Ordering in Two Isostructural Copper(II) Mesoxalate Metal–Organic Frameworks. Beatriz Gil-Hernández, Stanislav Savvin, Gamall Makhloufi, Pedro Núñez, Christoph Janiak, and Joaquín Sanchiz. Inorg. Chem.: February 4, 2015