Copper: the essentials

Copper appears in the periodic table at the top of Group 11 above silver and gold. Collectively these are sometimes referred to as the coinage metals, although in modern times these metals are used less frequently than in the past.

Copper is one of the most important metals. Copper is reddish with a bright metallic lustre. It is malleable, ductile, and a good conductor of heat and electricity (second only to silver in electrical conductivity). Its alloys, brass and bronze, are very important. Monel and gun metals also contain copper. Apparently the reason that policemen in the USA are nicknamed "cops" or "coppers" is to do with their uniforms which used to have copper buttons.

Copper metal is not particularly reactive and indeed is found as the free metal ("native") on occasion. Copper sulfate is [Cu(SO4)(OH2)4].H2O in the crystalline state; it is particularly well known and was often called blue vitriol. The oxidation number in most copper compounds is Cu(II), old name cupric, but there are many important Cu(I) compounds (cuprous) as well.

copper foil
Copper foil.

Copper (I) chloride salts imparts a blue colour to flames. The picture above shows the colour arising from adding cuprous chloride (CuCl) to a burning mixture of potassium chlorate and sucrose. This flame is relatively cool. Hotter flames burn green bacause of emission from copper atoms (only to be demonstrated by a professionally qualified chemist).

Copper: historical information

Copper was discovered by known since ancient times in unknown at not known. Origin of name: from the Latin word "cuprum" meaning the island of "Cyprus".

The discovery of copper dates from prehistoric times. There are reports of copper beads dating back to 9000BC found in Iraq. Methods for refining copper from its ores were discovered around 5000BC and a 1000 or so years later it was being used in pottery in North Africa.

Part of the reason for it being used so early is simply that it is relatively easy to shape. However it is somewhat too soft for many tools and around 5000 years ago it was discovered that when copper is mixed with other metals the resulting alloys are harder than copper itself. As examples, brass is a mixture of copper and zinc while bronze is a mixture of copper and tin.

Copper is one of the elements which has an alchemical symbol, shown below (alchemy is an ancient pursuit concerned with, for instance, the transformation of other metals into gold). {{floatR}}alchemical symbol of copper{{/floatR}}

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for copper is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.]

Dalton's symbol for copper

Copper around us Read more »

Copper is essential for all life, but only in small quantities. It is the key component of redox enzymes and of haemocyanin.

Copper is sometimes found as the free element and is present in many minerals. Important deposits are located in Canada, Chile, Germany, Italy, Peru, U.S.A., Zambia, and Zaire. The most important copper ores are the oxides, sulphides, and carbonates. One major ore, chalcopyrite (copper pyrite), CuFeS2 accounts for about 50% of all deposits.

Abundances for cobalt in a number of different environments. More abundance data »
Location ppb by weight ppb by atoms Links
Universe 60 1 Chemical elements abundance by weight in the universe on a miniature periodic table spark table
Crustal rocks 68000 22000 Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark table
Human 1000 ppb by weight 99 atoms relative to C = 1000000 Chemical elements abundance by weight in humans on a miniature periodic table spark table

Physical properties Read more »

Heat properties Read more »

Crystal structure Read more »

The solid state structure of copper is: ccp (cubic close-packed).

Copper: orbital properties Read more »

Copper atoms have 29 electrons and the shell structure is 2.8.18.1. The ground state electronic configuration of neutral Copper is [Ar].3d10.4s1 and the term symbol of Copper is 2S1/2.

Isolation

Isolation: copper metal is readily available commercially so it is not normally necesary to make it in the laboratory. Most copper production is based upon sulphide ores containing little copper but quite a lot of iron. New cleaner technologies are now important but older processes present major environmental problems. Complex procedures are used initially to form a form of copper sulphide appropriate for final reduction via a copper(I) oxide. The resulting crude copper is purified using an electrolytic procedure involving plating onto pure copper cathodes.

2Cu2S + 3O2 → 2Cu2O + 2SO2

2Cu2O + Cu2S → 6Cu + SO2

Notably, the purification step leaves an "anode slime" which contains useful amounts of silver and gold.

Copper isotopes Read more »

Both isotopes of Copper, Cu-63 and Cu-65, are used to study copper metabolism and gastrointestinal diseases. Cu-63 is used for production of medical radioisotope Zn-62 and can also be used for the production of Cu-64 which is used in cancer diagnosis and treatment. Cu-65 has also been proposed as a precursor for the (cyclotron) production of Cu-64.

Table. Stables isotopes of cobalt.
Isotope Mass
/Da
Natural
abund.
(atom %)
Nuclear
spin (I)
Nuclear
magnetic
moment (μ/μN)
63Cu 62.9295989 (17) 69.17 (3) 3/2 2.2233
65Cu 64.9277929 (20) 30.83 (3) 3/2 2.3817

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