Instruct: Given a question, retrieve passages that can help answer the question.
Query: What is the origin of the symbol Cu for Copper?
Copper is a chemical element with symbol Cu (from Latin: cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.
Before the Great Oxygenation Event, copper was not readily available for living organisms. Most early copper was Cu and Cu. This oxidation state of copper is not very soluble in water. One billion years ago, after the great oxidation event the oxygen pressure rose sufficiently to oxidise Cu to Cu, increasing its solubility in water. As a result, the copper became much more available for living organisms.
Copper acetate hydrate adopts the paddle wheel structure seen also for related Rh(II) and Cr(II) tetraacetates. One oxygen atom on each acetate is bound to one copper at 1.97 Å (197 pm). Completing the coordination sphere are two water ligands, with Cu–O distances of 2.20 Å (220 pm). The two five-coordinate copper atoms are separated by only 2.62 Å (262 pm), which is close to the Cu–Cu separation in metallic copper. The two copper centers interact resulting in a diminishing of the magnetic moment such that near 90 K, Cu(OAc)(HO) is essentially diamagnetic due to cancellation of the two opposing spins. Cu(OAc)(HO) was a critical step in the development of modern theories for antiferromagnetic coupling.
Copper occurs in its native form in Chile, China, Mexico, Russia and the USA. Various natural ores of copper are: copper pyrites (CuFeS), cuprite or ruby copper (CuO), copper glance (CuS), malachite, (Cu(OH)CuCO), and azurite (Cu(OH)2CuCO).
Many aspects of copper homeostasis are known at the molecular level. Copper's essentiality is due to its ability to act as an electron donor or acceptor as its oxidation state fluxes between Cu(cuprous) and Cu (cupric). As a component of about a dozen cuproenzymes, copper is involved in key redox (i.e., oxidation-reduction) reactions in essential metabolic processes such as mitochondrial respiration, synthesis of melanin, and cross-linking of collagen. Copper is an integral part of the antioxidant enzyme, copper-zinc superoxide dismutase (Cu,Zn-SOD), and has a role in iron homeostasis as a cofactor in ceruloplasmin. A list of some key copper-containing enzymes and their functions is summarized below:
The cations associate with the anions in the solution. This cations are reduced at the cathode to deposit in the metallic, zero valence state. For example, for copper plating, in an acid solution, copper is oxidized at the anode to Cu by losing two electrons. The Cu associates with the anion in the solution to form copper(II) sulfate. At the cathode, the Cu is reduced to metallic copper by gaining two electrons. The result is the effective transfer of copper from the anode source to a plate covering the cathode.
Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula Cu(OAc) where AcO is acetate (). The hydrated derivative, which contains one molecule of water for each Cu atom, is available commercially. Anhydrous Cu(OAc) is a dark green crystalline solid, whereas Cu(OAc)(HO) is more bluish-green. Since ancient times, copper acetates of some form have been used as fungicides and green pigments. Today, copper acetates are used as reagents for the synthesis of various inorganic and organic compounds. Copper acetate, like all copper compounds, emits a blue-green glow in a flame. The mineral hoganite is a naturally occurring form of copper(II) acetate.
CuS can be prepared by heating copper strongly in sulfur vapour or HS. The reaction of copper powder in molten sulfur rapidly produces CuS, whereas pellets of copper require much higher temperature.
CuS reacts with oxygen to form SO:
In the production of copper two thirds of the molten copper sulfide is oxidised as above, and the CuO reacts with unoxidised CuS to give Cu metal:
The process for copper is very similar, but the efficiency and kinetics depend on the copper mineralogy. The most efficient minerals are supergene minerals such as chalcocite, CuS and covellite, CuS. The main copper mineral chalcopyrite (CuFeS) is not leached very efficiently, which is why the dominant copper-producing technology remains flotation, followed by smelting and refining. The leaching of CuFeS follows the two stages of being dissolved and then further oxidised, with Cu ions being left in solution.
Prominent copper sulfide minerals include CuS (chalcocite) and CuS (covellite). In the mining industry, the minerals bornite or chalcopyrite, which consist of mixed copper-iron sulfides, are often referred to as "copper sulfides". In chemistry, a "binary copper sulfide" is any binary chemical compound of the elements copper and sulfur. Whatever their source, copper sulfides vary widely in composition with 0.5 ≤ Cu/S ≤ 2, including numerous non-stoichiometric compounds.
Copper (Cu) has two stable isotopes, Cu and Cu, along with 27 radioisotopes. The most stable of these is Cu with a half-life of 61.83 hours. The least stable is Cu with a half-life of approximately 75 ns. Most have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β decay, while isotopes with atomic masses above 65 tend to undergo β decay. Cu decays by both β and β.
A copper-molybdenum (Cu-Mo) system originated in both the Central Asian Orogenic Belt (North) and the Qinling Orogenic Belt (South).
The Central Asian Orgenic belt ore deposits occurred in arc complexes. They formed from the closure of Paleo-Asian ocean. The subduction generated copper and molybdenum Cu-Mo mineralization in the lithosphere block margins. Duobaoshan Cu and Bainaimiao Cu-Mo deposits are found in granodiorite. Tonghugou deposits occur with the copper ore chalcopyrite. North China hosted a large reserve of molybdenum with more than 70 ore bodies found in the Northern margin of the craton.
The Cu(0)-mediated RDRP mechanism showed that induction period is originated from the accumulation of soluble copper species during that initial unstable stage. It was demonstrated that Cu(I) act as a powerful activator even under its disproportionation favored conditions (in MeTREN/DMSO system), whilst Cu(0) also can activate dormant species to some extent and both disproportionation and comproportionation coexist. In other words, the mechanism lies between SET-LRP and SARA ATRP. The overall effect of disproportionation and comproportionation depends on the thermodynamic and kinetic condition of the experiments (such as equilibrium constant and the concentrations of Cu(I) and Cu(II) in nonpolar and polar solvents).
Copper(I) sulfide is a copper sulfide, a chemical compound of copper and sulfur. It has the chemical compound CuS. It is found in nature as the mineral chalcocite. It has a narrow range of stoichiometry ranging from CuS to CuS.
Plastocyanin is one of the family of blue copper proteins that are involved in electron transfer reactions. The copper-binding site is described as distorted trigonal pyramidal. The trigonal plane of the pyramidal base is composed of two nitrogen atoms (N and N) from separate histidines and a sulfur (S) from a cysteine. Sulfur (S) from an axial methionine forms the apex. The distortion occurs in the bond lengths between the copper and sulfur ligands. The Cu−S contact is shorter (207 pm) than Cu−S (282 pm).
The elongated Cu−S bonding destabilizes the Cu(II) form and increases the redox potential of the protein. The blue color (597 nm peak absorption) is due to the Cu−S bond where S(pπ) to Cu(d) charge transfer occurs.
Cu(OH)Cl can be prepared by air oxidation of Cu(I)Cl in brine solution. The Cu(I)Cl solution is usually made by reduction of CuCl solutions over copper metal. A CuCl solution with concentrated brine is contacted with copper metal until the Cu(II) is completely reduced. The resulting Cu(I)Cl is then heated to 60 ~ 90 °C and aerated to effect the oxidation and hydrolysis. The oxidation reaction can be performed with or without the copper metal. The precipitated product is separated and the mother liquor containing CuCl and NaCl, is recycled back to the process (eq. 6 ~ 7).
In the periodic table, copper's symbol is Cu, which derives from Cupra, Latin for copper.
Covellite (CuS) belongs to the binary copper sulfides group, which has the formula CuS and can have a wide-ranging copper/sulfur ratio from 1:2 to 2:1 (Cu/S)., However this series is by no means a continuous one and the width of the homogeneity range of covellite CuS is narrow. Materials rich in sulfur CuS where x~ 1.1- 1.2 do exist but they exhibit "superstructures" a modulation of the hexagonal ground plane of the structure spanning a number of adjacent unit cells. This indicates that several of covellite's special properties are the result of molecular structure at this level. Even though the peculiar monovalent nature of copper in sulfides has been known since the 1980s there are many places in the later literature, even in standard texts, where the divalent copper idea pops up again.
The reaction mechanism sequence is deprotonation of the amine, coordination of the amine to the copper(II), transmetallation (transferring the alkyl boron group to copper and the copper acetate group to boron), oxidation of Cu(II) to Cu(III) by oxygen and finally reductive elimination of Cu(III) to Cu(I) with formation of the product. Direct reductive elimination of Cu(II) to Cu(0) also takes place but is very slow. In catalytic systems oxygen also regenerates the Cu(II) catalyst.
Copper is a chemical element with symbol Cu and atomic number 29.
The molecular structure of the GHK copper complex (GHK-Cu) has been determined X-ray crystallography, EPR spectroscopy, X-ray absorption spectroscopy, NMR spectroscopy, as well as other methods such as titration. In the GHK-Cu complex, the Cu (II) ion is coordinated by the nitrogen from the imidazole side chain of the histidine, another nitrogen from the alpha-amino group of glycine and the deprotonated amide nitrogen of the glycine–histidine peptide bond. 
Since such a structure couldn’t explain a high stability constant of the GHK-Cu complex (log 10 =16.44 vs. 8.68 of the GH copper complex, which is similar to the GHK-Cu structure), it was proposed that another amino group participates in the complex formation. Cu(II) is also coordinated by the oxygen from the carboxyl group of the lysine from the neighboring complex. Another carboxyl group of lysine from a neighboring complex provides the apical oxygen, resulting in the square-planar pyramid configuration. 
Many researchers proposed that at the physiological pH, GHK-Cu complexes can form binary and ternary structures which may involve amino acid histidine and/or the copper binding region of the albumin molecule. Lau and Sarkar found also that GHK can easily obtain copper 2+ bound to other molecules such as the high affinity copper transport site on plasma albumin (albumin binding constant log 10 =16.2 vs. GHK binding constant 16 log 10 =16.44). It has been established that copper (II) redox activity is silenced when copper ions are complexed with the GHK tripeptide, which allows the delivery of non-toxic copper into the cell.
Understanding this synergistic effect is crucial to understand the existence of the induction period. As the relative concentrations of different copper species are far from the polymerization equilibrium (activation/deactivation) ratio, the disproportionation equilibrium is thermodynamically favoured and dominates the mutual conversion of the different valent copper spices in the initial stage, resulting the accumulation of the dissolved copper species. Once the [Cu(I)]/[Cu(II)] ratio approach to a critical value (i.e. the polymerization equilibrium ratio), the polymerization would be accelerated and the induction period is ceased. Therefore, if the dissolved copper species – either Cu(I) or Cu(II) – are added, the initial concentration ratio is changed and the polymerization equilibrium is favoured, resulting an instant polymerisation.
Copper sulfide crystallizes in the hexagonal crystal system, and this is the form of the mineral covellite. There is also an amorphous high pressure form which on the basis of the Raman spectrum has been described as having a distorted covellite structure. An amorphous room temperature semiconducting form produced by the reaction of a Cu(II) ethylenediamine complex with thiourea has been reported, which transforms to the crystalline covellite form at 30 °C.
The crystal structure of covellite has been reported several times, and whilst these studies are in general agreement on assigning the space group P6/mmc there are small discrepancies in bond lengths and angles between them. The structure was described as "extraordinary" by Wells and is quite different from copper(II) oxide, but similar to CuSe (klockmannite). The covellite unit cell contains 6 formula units (12 atoms) in which:
The formulation of copper sulfide as CuS (i.e. containing no sulfur-sulfur bond) is clearly incompatible with the crystal structure, and also at variance with the observed diamagnetism as a Cu(II) compound would have a d configuration and be expected to be paramagnetic. 
Studies using XPS indicate that all of the copper atoms have an oxidation state of +1. This contradicts a formulation based on the crystal structure and obeying the octet rule that is found in many textbooks (e.g.) describing CuS as containing both Cu and Cu i.e. (Cu)Cu(S)S. An alternative formulation as (Cu)(S)(S) was proposed and supported by calculations.
The formulation should not be interpreted as containing radical anion, but rather that there is a delocalized valence "hole".
Electron paramagnetic resonance studies on the precipitation of Cu(II) salts indicates that the reduction of Cu(II) to Cu(I) occurs in solution.
Copper peptide GHK-Cu is widely used in anti-aging cosmetics (INCI name: Copper tripeptide-1). Several controlled facial studies confirmed anti-aging, firming and anti-wrinkle activity of copper peptide GHK-Cu.
The first of these symbols were intended to be fully universal. Since Latin was the common language of science at that time, they were abbreviations based on the Latin names of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin "natrium". The same applies to "W" (wolfram) for tungsten, "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "K" (kalium) for potassium, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and "Sb" (stibium) for antimony.