A coffeehouse, coffee shop, or café is an establishment that serves coffee, related coffee drinks, – depending on country – other drinks including alcoholic. Some coffeehouses may serve cold drinks such as iced tea. A coffeehouse may serve some type of food, such as light snacks, muffins or other pastries. Coffeehouses range from owner-operated small businesses to large multinational corporations. While café may refer to a coffeehouse, the term "cafe" refers to a diner, British cafe, "greasy spoon", transport cafe, teahouse or tea room, or other casual eating and drinking place. A coffeehouse may share some of the same characteristics of a bar or restaurant, but it is different from a cafeteria. Many coffeehouses in the Middle East and in West Asian immigrant districts in the Western world offer shisha, flavored tobacco smoked through a hookah. Espresso bars are a type of coffeehouse that specializes in serving espresso and espresso-based drinks. From a cultural standpoint, coffeehouses serve as centers of social interaction: the coffeehouse provides patrons with a place to congregate, read, entertain one another, or pass the time, whether individually or in small groups.
Since the development of Wi-Fi, coffeehouses with this capability have become places for patrons to access the Internet on their laptops and tablet computers. A coffeehouse can serve as an informal club for its regular members; as early as the 1950s Beatnik era and the 1960s folk music scene, coffeehouses have hosted singer-songwriter performances in the evening. The most common English spelling, café, is the French and Spanish spelling, was adopted by English-speaking countries in the late-19th century; as English makes little use of diacritics, anglicisation tends to omit them and to place the onus on the readers to remember how it is pronounced without the presence of the accent. Thus the spelling cafe has become common in English-language usage throughout the world for the less formal, i.e. "greasy spoon" variety. The Italian spelling, caffè, is sometimes used in English. In southern England around London in the 1950s, the French pronunciation was facetiously altered to and spelt caff; the English words coffee and café derive from the Italian word for coffee, caffè—first attested as caveé in Venice in 1570—and in turn derived from Arabic qahwa.
The Arabic term qahwa referred to a type of wine, but after the wine ban by Islam, the name was transferred to coffee because of the similar rousing effect it induced. European knowledge of coffee came through European contact with Turkey via Venetian-Ottoman trade relations; the English word café to describe a restaurant that serves coffee and snacks rather than the word coffee that describes the drink, is derived from the French café. The first café is believed to have opened in France in 1660; the translingual word root /kafe/ appears in many European languages with various naturalized spellings, including. Coffeehouses in Mecca became a concern of imams who viewed them as places for political gatherings and drinking, they were banned for Muslims between 1512 and 1524. The Ottoman chronicler İbrahim Peçevi reports in his writings about the opening of the first coffeehouse in Istanbul: Until the year 962, in the High, God-Guarded city of Constantinople, as well as in Ottoman lands coffee and coffee-houses did not exist.
About that year, a fellow called Hakam from Aleppo and a wag called Shams from Damascus came to the city. Various legends involving the introduction of coffee to Istanbul at a "Kiva Han" in the late-15th century circulate in culinary tradition, but with no documentation; the 17th century French traveler and writer Jean Chardin gave a lively description of the Persian coffeehouse scene: People engage in conversation, for it is there that news is communicated and where those interested in politics criticize the government in all freedom and without being fearful, since the government does not heed what the people say. Innocent games... resembling checkers and chess, are played. In addition, mollas and poets take turns telling stories in verse or in prose; the narrations by the mollas and the dervishes are moral lessons, like our sermons, but it is not considered scandalous not to pay attention to them. No one is forced to give up his conversation because of it. A molla will stand up in the middle, or at one end of the qahveh-khaneh, begin to preach in a loud voice, or a dervish enters all of a sudden, chastises the assembled on the vanity of the world and its material goods.
It happens that two or three people talk at the same time, one on one side, the other on the opposite, sometimes one will be a preacher and the other a storyteller. In the 17th century, coffee appeared for the first time in Europe outside the Ottoman Empire, coffeehouses were established, soon becoming popular; the first coffeehouses appeared in Venice in 1629, due to the traffic between La Serenissima and the Ottomans. The first coffeehouse in England was set up in Oxford in 1650 by a Jewish man named Jacob at the Angel in the parish of St Peter in
Silver is a chemical element with symbol Ag and atomic number 47. A soft, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, reflectivity of any metal; the metal is found in the Earth's crust in the pure, free elemental form, as an alloy with gold and other metals, in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold and zinc refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes alongside gold: while it is more abundant than gold, it is much less abundant as a native metal, its purity is measured on a per-mille basis. As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Other than in currency and as an investment medium, silver is used in solar panels, water filtration, ornaments, high-value tableware and utensils, in electrical contacts and conductors, in specialized mirrors, window coatings, in catalysis of chemical reactions, as a colorant in stained glass and in specialised confectionery.
Its compounds are used in X-ray film. Dilute solutions of silver nitrate and other silver compounds are used as disinfectants and microbiocides, added to bandages and wound-dressings and other medical instruments. Silver is similar in its physical and chemical properties to its two vertical neighbours in group 11 of the periodic table and gold, its 47 electrons are arranged in the configuration 4d105s1 to copper and gold. This distinctive electron configuration, with a single electron in the highest occupied s subshell over a filled d subshell, accounts for many of the singular properties of metallic silver. Silver is an soft and malleable transition metal, though it is less malleable than gold. Silver crystallizes in a face-centered cubic lattice with bulk coordination number 12, where only the single 5s electron is delocalized to copper and gold. Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent character and are weak; this observation explains the low high ductility of single crystals of silver.
Silver has a brilliant white metallic luster that can take a high polish, and, so characteristic that the name of the metal itself has become a colour name. Unlike copper and gold, the energy required to excite an electron from the filled d band to the s-p conduction band in silver is large enough that it no longer corresponds to absorption in the visible region of the spectrum, but rather in the ultraviolet. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm. At wavelengths shorter than 450 nm, silver's reflectivity is inferior to that of aluminium and drops to zero near 310 nm. High electrical and thermal conductivity is common to the elements in group 11, because their single s electron is free and does not interact with the filled d subshell, as such interactions lower electron mobility; the electrical conductivity of silver is the greatest of all metals, greater than copper, but it is not used for this property because of the higher cost.
An exception is in radio-frequency engineering at VHF and higher frequencies where silver plating improves electrical conductivity because those currents tend to flow on the surface of conductors rather than through the interior. During World War II in the US, 13540 tons of silver were used in electromagnets for enriching uranium because of the wartime shortage of copper. Pure silver has the highest thermal conductivity of any metal, although the conductivity of carbon and superfluid helium-4 are higher. Silver has the lowest contact resistance of any metal. Silver forms alloys with copper and gold, as well as zinc. Zinc-silver alloys with low zinc concentration may be considered as face-centred cubic solid solutions of zinc in silver, as the structure of the silver is unchanged while the electron concentration rises as more zinc is added. Increasing the electron concentration further leads to body-centred cubic, complex cubic, hexagonal close-packed phases. Occurring silver is composed of two stable isotopes, 107Ag and 109Ag, with 107Ag being more abundant.
This equal abundance is rare in the periodic table. The atomic weight is 107.8682 u. Both isotopes of silver are produced in stars via the s-process, as well as in supernovas via the r-process. Twenty-eight radioisotopes have been characterized, the most stable being 105Ag with a half-life of 41.29 days, 111Ag with a half-life of 7.45 days, 112Ag with a half-life of 3.13 hours. Silver has numerous nuclear isomers, the most stable being 108mAg, 110mAg and 106mAg. All of the remaining radioactive isotopes have half-lives of less than an hour, the majority of these have half-lives of less than three minutes. Isotopes of silver range in relative atomic mass from 92.950 u
Bank of England
The Bank of England is the central bank of the United Kingdom and the model on which most modern central banks have been based. Established in 1694 to act as the English Government's banker, still one of the bankers for the Government of the United Kingdom, it is the world's eighth-oldest bank, it was owned by stockholders from its foundation in 1694 until it was nationalised in 1946. The Bank became an independent public organisation in 1998, wholly owned by the Treasury Solicitor on behalf of the government, but with independence in setting monetary policy; the Bank is one of eight banks authorised to issue banknotes in the United Kingdom, has a monopoly on the issue of banknotes in England and Wales and regulates the issue of banknotes by commercial banks in Scotland and Northern Ireland. The Bank's Monetary Policy Committee has a devolved responsibility for managing monetary policy; the Treasury has reserve powers to give orders to the committee "if they are required in the public interest and by extreme economic circumstances", but such orders must be endorsed by Parliament within 28 days.
The Bank's Financial Policy Committee held its first meeting in June 2011 as a macroprudential regulator to oversee regulation of the UK's financial sector. The Bank's headquarters have been in London's main financial district, the City of London, on Threadneedle Street, since 1734, it is sometimes known as The Old Lady of Threadneedle Street, a name taken from a satirical cartoon by James Gillray in 1797. The road junction outside is known as Bank junction; as a regulator and central bank, the Bank of England has not offered consumer banking services for many years, but it still does manage some public-facing services such as exchanging superseded bank notes. Until 2016, the bank provided personal banking services as a privilege for employees. England's crushing defeat by France, the dominant naval power, in naval engagements culminating in the 1690 Battle of Beachy Head, became the catalyst for England rebuilding itself as a global power. England had no choice. No public funds were available, the credit of William III's government was so low in London that it was impossible for it to borrow the £1,200,000 that the government wanted.
To induce subscription to the loan, the subscribers were to be incorporated by the name of the Governor and Company of the Bank of England. The Bank was given exclusive possession of the government's balances, was the only limited-liability corporation allowed to issue bank notes; the lenders would give the government cash and issue notes against the government bonds, which can be lent again. The £1.2m was raised in 12 days. As a side effect, the huge industrial effort needed, including establishing ironworks to make more nails and advances in agriculture feeding the quadrupled strength of the navy, started to transform the economy; this helped the new Kingdom of Great Britain – England and Scotland were formally united in 1707 – to become powerful. The power of the navy made Britain the dominant world power in the late 18th and early 19th centuries; the establishment of the bank was devised by Charles Montagu, 1st Earl of Halifax, in 1694. The plan of 1691, proposed by William Paterson three years before, had not been acted upon.
58 years earlier, in 1636, Financier to the king, Philip Burlamachi, had proposed the same idea in a letter addressed to Sir Francis Windebank. He proposed a loan of £1.2m to the government. The royal charter was granted on 27 July through the passage of the Tonnage Act 1694. Public finances were in such dire condition at the time that the terms of the loan were that it was to be serviced at a rate of 8% per annum, there was a service charge of £4,000 per annum for the management of the loan; the first governor was Sir John Houblon, depicted in the £50 note issued in 1994. The charter was renewed in 1742, 1764, 1781; the Bank's original home was in Walbrook, a street in the City of London, where during reconstruction in 1954 archaeologists found the remains of a Roman temple of Mithras. The Bank moved to its current location in Threadneedle Street in 1734, thereafter acquired neighbouring land to create the site necessary for erecting the Bank's original home at this location, under the direction of its chief architect Sir John Soane, between 1790 and 1827.
When the idea and reality of the national debt came about during the 18th century, this was managed by the Bank. During the American war of independence, business for the Bank was so good that George Washington remained a shareholder throughout the period. By the charter renewal in 1781 it was the bankers' bank – keeping enough gold to pay its notes on demand until 26 February 1797 when war had so diminished gold reserves that – following an invasion scare caused by the Battle of Fishguard days earlier – the government prohibited the Bank from paying out in gold by the passing of the Bank Restriction Act 1797; this prohibition lasted until 1821. The 1844 Bank Charter Act tied the issue of notes to the gold reserves and gave the Bank sol
United Kingdom company law
The United Kingdom company law regulates corporations formed under the Companies Act 2006. Governed by the Insolvency Act 1986, the UK Corporate Governance Code, European Union Directives and court cases, the company is the primary legal vehicle to organise and run business. Tracing their modern history to the late Industrial Revolution, public companies now employ more people and generate more of wealth in the United Kingdom economy than any other form of organisation; the United Kingdom was the first country to draft modern corporation statutes, where through a simple registration procedure any investors could incorporate, limit liability to their commercial creditors in the event of business insolvency, where management was delegated to a centralised board of directors. An influential model within Europe, the Commonwealth and as an international standard setter, UK law has always given people broad freedom to design the internal company rules, so long as the mandatory minimum rights of investors under its legislation are complied with.
Company law, or corporate law, can be broken down into two main fields. Corporate governance in the UK mediates the rights and duties among shareholders, employees and directors. Since the board of directors habitually possesses the power to manage the business under a company constitution, a central theme is what mechanisms exist to ensure directors' accountability. UK law is "shareholder friendly" in that shareholders, to the exclusion of employees exercise sole voting rights in the general meeting; the general meeting holds a series of minimum rights to change the company constitution, issue resolutions and remove members of the board. In turn, directors owe a set of duties to their companies. Directors must carry out their responsibilities with competence, in good faith and undivided loyalty to the enterprise. If the mechanisms of voting do not prove enough for minority shareholders, directors' duties and other member rights may be vindicated in court. Of central importance in public and listed companies is the securities market, typified by the London Stock Exchange.
Through the Takeover Code the UK protects the right of shareholders to be treated and trade their shares. Corporate finance concerns the two money raising options for limited companies. Equity finance involves the traditional method of issuing shares to build up a company's capital. Shares can contain any rights the company and purchaser wish to contract for, but grant the right to participate in dividends after a company earns profits and the right to vote in company affairs. A purchaser of shares is helped to make an informed decision directly by prospectus requirements of full disclosure, indirectly through restrictions on financial assistance by companies for purchase of their own shares. Debt finance means getting loans for the price of a fixed annual interest repayment. Sophisticated lenders, such as banks contract for a security interest over the assets of a company, so that in the event of default on loan repayments they may seize the company's property directly to satisfy debts. Creditors are to some extent, protected by courts' power to set aside unfair transactions before a company goes under, or recoup money from negligent directors engaged in wrongful trading.
If a company is unable to pay its debts as they fall due, UK insolvency law requires an administrator to attempt a rescue of the company. If rescue proves impossible, a company's life ends when its assets are liquidated, distributed to creditors and the company is struck off the register. If a company becomes insolvent with no assets it can be wound up by a creditor, for a fee, or more by the tax creditor. Company law in its modern shape dates from the mid-19th century, however an array of business associations developed long before. In medieval times traders would do business through common law constructs, such as partnerships. Whenever people acted together with a view to profit, the law deemed. Early guilds and livery companies were often involved in the regulation of competition between traders; as England sought to build a mercantile Empire, the government created corporations under a Royal Charter or an Act of Parliament with the grant of a monopoly over a specified territory. The best known example, established in 1600, was the British East India Company.
Queen Elizabeth I granted it the exclusive right to trade with all countries to the east of the Cape of Good Hope. Corporations at this time would act on the government's behalf, bringing in revenue from its exploits abroad. Subsequently, the Company became integrated with British military and colonial policy, just as most UK corporations were dependent on the British navy's ability to control trade routes on the high seas. A similar chartered company, the South Sea Company, was established in 1711 to trade in the Spanish South American colonies, but met with less success; the South Sea Company's monopoly rights were backed by the Treaty of Utrecht, signed in 1713 as a settlement following the War of Spanish Succession, which gave the United Kingdom an assiento to trade, to sell slaves in the region for thirty years. In fact the Spanish let only one ship a year enter. Unaware of the problems, investors in the UK, enticed by company promoters' extravagant promises of profit, bought thousands of shares.
By 1717, the South Sea Company was so wealthy. This accelerated the inflation of the share price further, as did the Royal Exchange and London Assurance Corporation Act 1719, whi
Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron; the free element, produced by reductive smelting, is a hard, silver-gray metal. Cobalt-based blue pigments have been used since ancient times for jewelry and paints, to impart a distinctive blue tint to glass, but the color was thought by alchemists to be due to the known metal bismuth. Miners had long used the name kobold ore for some of the blue-pigment producing minerals. In 1735, such ores were found to be reducible to a new metal, this was named for the kobold. Today, some cobalt is produced from one of a number of metallic-lustered ores, such as for example cobaltite; the element is however more produced as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo and Zambia yields most of the global cobalt production; the DRC alone accounted for more than 50% of world production in 2016, according to Natural Resources Canada.
Cobalt is used in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt aluminate give a distinctive deep blue color to glass, inks and varnishes. Cobalt occurs as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high energy gamma rays. Cobalt is the active center of a group of coenzymes called cobalamins. Vitamin B12, the best-known example of the type, is an essential vitamin for all animals. Cobalt in inorganic form is a micronutrient for bacteria and fungi. Cobalt is a ferromagnetic metal with a specific gravity of 8.9. The Curie temperature is 1,115 °C and the magnetic moment is 1.6–1.7 Bohr magnetons per atom. Cobalt has a relative permeability two-thirds. Metallic cobalt occurs as two crystallographic structures: fcc; the ideal transition temperature between the hcp and fcc structures is 450 °C, but in practice the energy difference between them is so small that random intergrowth of the two is common.
Cobalt is a weakly reducing metal, protected from oxidation by a passivating oxide film. It is attacked by halogens and sulfur. Heating in oxygen produces Co3O4 which loses oxygen at 900 °C to give the monoxide CoO; the metal reacts with fluorine at 520 K to give CoF3. It does not react with hydrogen gas or nitrogen gas when heated, but it does react with boron, phosphorus and sulfur. At ordinary temperatures, it reacts with mineral acids, slowly with moist, but not with dry, air. Common oxidation states of cobalt include +2 and +3, although compounds with oxidation states ranging from −3 to +5 are known. A common oxidation state for simple compounds is +2; these salts form the pink-colored metal aquo complex 2+ in water. Addition of chloride gives the intensely blue 2−. In a borax bead flame test, cobalt shows deep blue in both reducing flames. Several oxides of cobalt are known. Green cobalt oxide has rocksalt structure, it is oxidized with water and oxygen to brown cobalt hydroxide. At temperatures of 600 -- 700 °C, CoO oxidizes to the blue cobalt oxide.
Black cobalt oxide is known. Cobalt oxides are antiferromagnetic at low temperature: CoO and Co3O4, analogous to magnetite, with a mixture of +2 and +3 oxidation states; the principal chalcogenides of cobalt include the black cobalt sulfides, CoS2, which adopts a pyrite-like structure, cobalt sulfide. Four dihalides of cobalt are known: cobalt fluoride, cobalt chloride, cobalt bromide, cobalt iodide; these halides exist in hydrated forms. Whereas the anhydrous dichloride is blue, the hydrate is red; the reduction potential for the reaction Co3+ + e− → Co2+ is +1.92 V, beyond that for chlorine to chloride, +1.36 V. Consequently and chloride would result in the cobalt being reduced to cobalt; because the reduction potential for fluorine to fluoride is so high, +2.87 V, cobalt fluoride is one of the few simple stable cobalt compounds. Cobalt fluoride, used in some fluorination reactions, reacts vigorously with water; as for all metals, molecular compounds and polyatomic ions of cobalt are classified as coordination complexes, that is, molecules or ions that contain cobalt linked to several ligands.
The principles of electronegativity and hardness–softness of a series of ligands can be used to explain the usual oxidation state of cobalt. For example, Co+3 complexes tend to have ammine ligands; because phosphorus is softer than nitrogen, phosphine ligands tend to feature the softer Co2+ and Co+, an example being triscobalt chloride. The more electronegative oxide and fluoride can stabilize Co4+ and Co5+ derivatives, e.g. caesium hexafluorocobaltate and potassium percobaltate. Alfred Werner, a Nobel-prize winning pioneer in coordination chemistry, worked with compounds of empirical formula 3+. One of the isomers
Chile the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, the Drake Passage in the far south. Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez and Easter Island in Oceania. Chile claims about 1,250,000 square kilometres of Antarctica, although all claims are suspended under the Antarctic Treaty; the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. The small central area dominates in terms of population and agricultural resources, is the cultural and political center from which Chile expanded in the late 19th century when it incorporated its northern and southern regions. Southern Chile is rich in forests and grazing lands, features a string of volcanoes and lakes; the southern coast is a labyrinth of fjords, canals, twisting peninsulas, islands.
Spain conquered and colonized the region in the mid-16th century, replacing Inca rule in the north and centre, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a stable authoritarian republic. In the 19th century, Chile saw significant economic and territorial growth, ending Mapuche resistance in the 1880s and gaining its current northern territory in the War of the Pacific after defeating Peru and Bolivia. In the 1960s and 1970s, the country experienced severe left-right political polarization and turmoil; this development culminated with the 1973 Chilean coup d'état that overthrew Salvador Allende's democratically elected left-wing government and instituted a 16-year-long right-wing military dictatorship that left more than 3,000 people dead or missing. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a center-left coalition which ruled through four presidencies until 2010.
The modern sovereign state of Chile is among South America's most economically and stable and prosperous nations, with a high-income economy and high living standards. It leads Latin American nations in rankings of human development, income per capita, state of peace, economic freedom, low perception of corruption, it ranks high regionally in sustainability of the state, democratic development. Chile is a member of the Organisation for Economic Co-operation and Development, joining in 2010, it has the lowest homicide rate in the Americas after Canada. Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile. According to 17th-century Spanish chronicler Diego de Rosales, the Incas called the valley of the Aconcagua "Chili" by corruption of the name of a Picunche tribal chief called Tili, who ruled the area at the time of the Incan conquest in the 15th century.
Another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Other theories say Chile may derive its name from a Native American word meaning either "ends of the earth" or "sea gulls". Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a bird locally known as trile; the Spanish conquistadors heard about this name from the Incas, the few survivors of Diego de Almagro's first Spanish expedition south from Peru in 1535–36 called themselves the "men of Chilli". Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such; the older spelling "Chili" was in use in English until at least 1900 before switching to "Chile". Stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating indigenous Peoples settled in fertile valleys and coastal areas of what is present-day Chile.
Settlement sites from early human habitation include Monte Verde, Cueva del Milodón and the Pali-Aike Crater's lava tube. The Incas extended their empire into what is now northern Chile, but the Mapuche resisted many attempts by the Inca Empire to subjugate them, despite their lack of state organization, they fought against his army. The result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. In 1520, while attempting to circumnavigate the globe, Ferdinand Magellan discovered the southern passage now named after him thus becoming the first European to set foot on what is now Chile; the next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, who came from Peru in 1535 seeking gold. The Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting; the conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarro's lieutenants, who founded the city of Santiago on 12 February 1541.
Although the Spanish did not find the extensive gold and silver they sought, they recognize
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion. So, pure native nickel is found in Earth's crust only in tiny amounts in ultramafic rocks, in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel has been traced as far back as 3500 BCE. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden.
The element's name comes from a mischievous sprite of German miner mythology, who personified the fact that copper-nickel ores resisted refinement into copper. An economically important source of nickel is the iron ore limonite, which contains 1–2% nickel. Nickel's other important ore minerals include pentlandite and a mixture of Ni-rich natural silicates known as garnierite. Major production sites include the Sudbury region in Canada, New Caledonia in the Pacific, Norilsk in Russia. Nickel is oxidized by air at room temperature and is considered corrosion-resistant, it has been used for plating iron and brass, coating chemistry equipment, manufacturing certain alloys that retain a high silvery polish, such as German silver. About 9% of world nickel production is still used for corrosion-resistant nickel plating. Nickel-plated objects sometimes provoke nickel allergy. Nickel has been used in coins, though its rising price has led to some replacement with cheaper metals in recent years. Nickel is one of four elements that are ferromagnetic at room temperature.
Alnico permanent magnets based on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is valuable in modern times chiefly in alloys. A further 10% is used for nickel-based and copper-based alloys, 7% for alloy steels, 3% in foundries, 9% in plating and 4% in other applications, including the fast-growing battery sector; as a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation, cathodes for batteries and metal surface treatments. Nickel is an essential nutrient for some microorganisms and plants that have enzymes with nickel as an active site. Nickel is a silvery-white metal with a slight golden tinge, it is one of only four elements that are magnetic at or near room temperature, the others being iron and gadolinium. Its Curie temperature is 355 °C; the unit cell of nickel is a face-centered cube with the lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm. This crystal structure is stable to pressures of at least 70 GPa.
Nickel belongs to the transition metals. It is hard and ductile, has a high for transition metals electrical and thermal conductivity; the high compressive strength of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to the formation and movement of dislocations. The nickel atom has two electron configurations, 3d8 4s2 and 3d9 4s1, which are close in energy – the symbol refers to the argon-like core structure. There is some disagreement. Chemistry textbooks quote the electron configuration of nickel as 4s2 3d8, which can be written 3d8 4s2; this configuration agrees with the Madelung energy ordering rule, which predicts that 4s is filled before 3d. It is supported by the experimental fact that the lowest energy state of the nickel atom is a 3d8 4s2 energy level the 3d8 4s2 3F, J = 4 level. However, each of these two configurations splits into several energy levels due to fine structure, the two sets of energy levels overlap; the average energy of states with configuration 3d9 4s1 is lower than the average energy of states with configuration 3d8 4s2.
For this reason, the research literature on atomic calculations quotes the ground state configuration of nickel as 3d9 4s1. The isotopes of nickel range in atomic weight from 48 u to 78 u. Occurring nickel is composed of five stable isotopes. Isotopes heavier than 62Ni cannot be formed by nuclear fusion without losing energy. Nickel-62 has the highest mean nuclear binding energy per nucleon of any nuclide, at 8.7946 MeV/nucleon. Its binding energy is greater than both 56Fe and 58Fe, more abundant elements incorrectly cited as having the most tightly-bound nuclides. Although this would seem to predict nickel-62 as the most abundant heavy element in the universe, the high rate of photodisintegration of nickel in stellar interiors causes iron to be by far the most abundant. Stable isotope nickel-60 is the daughter product of the extinct radionuclide 60Fe, whi