92-615: Odin Mine is a disused lead mine in the Peak District National Park, situated at grid reference SK133835 . It lies on a site of 25 hectares near the village of Castleton , England. It is the oldest documented mine in Derbyshire and is thought to be one of the oldest lead mines in England. The mine is a Scheduled Ancient Monument and has biological and geological significance within
184-433: A density of 11.34 g/cm , which is greater than that of common metals such as iron (7.87 g/cm ), copper (8.93 g/cm ), and zinc (7.14 g/cm ). This density is the origin of the idiom to go over like a lead balloon . Some rarer metals are denser: tungsten and gold are both at 19.3 g/cm , and osmium —the densest metal known—has a density of 22.59 g/cm , almost twice that of lead. Lead
276-503: A few hours, a phenomenon apparently caused by the heat realigning the lattice dislocations removing the colour. Irradiating the discoloured Blue John in a nuclear reactor can bring the colour back. Blue, unbanded fluorite occurs in many localities around the world. Within the UK, blue fluorspars are also found in County Durham , especially Weardale . Elsewhere, blue fluorspar is known in
368-492: A few radioactive isotopes. One of them is lead-210; although it has a half-life of only 22.2 years, small quantities occur in nature because lead-210 is produced by a long decay series that starts with uranium-238 (that has been present for billions of years on Earth). Lead-211, −212, and −214 are present in the decay chains of uranium-235, thorium-232, and uranium-238, respectively, so traces of all three of these lead isotopes are found naturally. Minute traces of lead-209 arise from
460-558: A neutron and become thallium-204; this undergoes beta decay to give stable lead-204; on capturing another neutron, it becomes lead-205, which has a half-life of around 17 million years. Further captures result in lead-206, lead-207, and lead-208. On capturing another neutron, lead-208 becomes lead-209, which quickly decays into bismuth-209. On capturing another neutron, bismuth-209 becomes bismuth-210, and this beta decays to polonium-210, which alpha decays to lead-206. The cycle hence ends at lead-206, lead-207, lead-208, and bismuth-209. In
552-466: A polyhedral vertex and contributes two electrons to each covalent bond along an edge from their sp hybrid orbitals, the other two being an external lone pair . They may be made in liquid ammonia via the reduction of lead by sodium . Lead can form multiply-bonded chains , a property it shares with its lighter homologs in the carbon group. Its capacity to do so is much less because the Pb–Pb bond energy
644-538: A purple-blue colour. It is now thought that the colour may be a physical phenomenon due to crystal lattice dislocation . If the regular arrangement of atoms in the fluorite molecules are disturbed or dislocated, then this may yield the blue colour in Blue John. The cause of these dislocations is unknown, but one possibility is that it is due to colloidal calcium, i.e. excess of calcium atoms needed to form fluorite. Blue John can be decolourised by heating it in an oven for
736-454: A rich vein of lead was struck: 41 men and eight women were working at the site and the mine reached 500 metres into the hillside beneath Mam Tor . Drainage problems in the mine meant that a proposal to build a low-level sough was put forward in 1772 but this was not completed for many years, probably not until the 1840s. It was driven up from Hollowford Brook at Trickett Bridge in Castleton to
828-416: A saw. They may be made into rough cuboids or cylinders ("rough-outs"), for turning as bowls and vases, or flat slices, for making jewellery. Rough-outs are glued to a metal chuck and turned on a lathe, sometimes using pieces of broken grinding wheels. The chuck is removed by heating the glue, or—if the operator is inclined—a sharp tap on the chuck with a spanner. A further resining stage may take place, before
920-437: A significant partial positive charge on lead. The result is a stronger contraction of the lead 6s orbital than is the case for the 6p orbital, making it rather inert in ionic compounds. The inert pair effect is less applicable to compounds in which lead forms covalent bonds with elements of similar electronegativity, such as carbon in organolead compounds. In these, the 6s and 6p orbitals remain similarly sized and sp hybridization
1012-438: A single decay chain). In total, 43 lead isotopes have been synthesized, with mass numbers 178–220. Lead-205 is the most stable radioisotope, with a half-life of around 1.70 × 10 years. The second-most stable is lead-202, which has a half-life of about 52,500 years, longer than any of the natural trace radioisotopes. Bulk lead exposed to moist air forms a protective layer of varying composition. Lead(II) carbonate
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#17328769432121104-420: A soft ornamental rock which they called murrhine , out of which drinking vessels were carved. Pliny describes the mineral as having a "great variety of colours" with "shades of purple and white with a mixture of the two". Whether this mineral was banded fluorite is uncertain, but it was apparently soft enough (like fluorite) to allow one particular man of consular rank to gnaw at the edges of his cup. There
1196-449: A structure, with every alternate layer of oxygen atoms absent. Negative oxidation states can occur as Zintl phases , as either free lead anions, as in Ba 2 Pb, with lead formally being lead(−IV), or in oxygen-sensitive ring-shaped or polyhedral cluster ions such as the trigonal bipyramidal Pb 5 ion, where two lead atoms are lead(−I) and three are lead(0). In such anions, each atom is at
1288-590: Is 6 times higher, copper 10 times, and mild steel 15 times higher); it can be strengthened by adding small amounts of copper or antimony . The melting point of lead—at 327.5 °C (621.5 °F) —is very low compared to most metals. Its boiling point of 1749 °C (3180 °F) is the lowest among the carbon-group elements. The electrical resistivity of lead at 20 °C is 192 nanoohm -meters, almost an order of magnitude higher than those of other industrial metals (copper at 15.43 nΩ·m ; gold 20.51 nΩ·m ; and aluminium at 24.15 nΩ·m ). Lead
1380-521: Is a chemical element ; it has symbol Pb (from Latin plumbum ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable , and also has a relatively low melting point . When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead
1472-516: Is a neurotoxin that accumulates in soft tissues and bones. It damages the nervous system and interferes with the function of biological enzymes , causing neurological disorders ranging from behavioral problems to brain damage, and also affects general health, cardiovascular, and renal systems. Lead's toxicity was first documented by ancient Greek and Roman writers, who noted some of the symptoms of lead poisoning , but became widely recognized in Europe in
1564-401: Is a superconductor at temperatures lower than 7.19 K ; this is the highest critical temperature of all type-I superconductors and the third highest of the elemental superconductors. Natural lead consists of four stable isotopes with mass numbers of 204, 206, 207, and 208, and traces of six short-lived radioisotopes with mass numbers 209–214 inclusive. The high number of isotopes
1656-420: Is a common constituent; the sulfate or chloride may also be present in urban or maritime settings. This layer makes bulk lead effectively chemically inert in the air. Finely powdered lead, as with many metals, is pyrophoric , and burns with a bluish-white flame. Fluorine reacts with lead at room temperature, forming lead(II) fluoride . The reaction with chlorine is similar but requires heating, as
1748-775: Is a mixed sulfide derived from galena; anglesite , PbSO 4 , is a product of galena oxidation; and cerussite or white lead ore, PbCO 3 , is a decomposition product of galena. Arsenic , tin , antimony , silver , gold , copper , bismuth are common impurities in lead minerals. World lead resources exceed two billion tons. Significant deposits are located in Australia, China, Ireland, Mexico, Peru, Portugal, Russia, United States. Global reserves—resources that are economically feasible to extract—totaled 88 million tons in 2016, of which Australia had 35 million, China 17 million, Russia 6.4 million. Typical background concentrations of lead do not exceed 0.1 μg/m in
1840-420: Is a relatively unreactive post-transition metal . Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases , and it tends to form covalent bonds . Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group . Exceptions are mostly limited to organolead compounds . Like
1932-426: Is a strong oxidizing agent, capable of oxidizing hydrochloric acid to chlorine gas. This is because the expected PbCl 4 that would be produced is unstable and spontaneously decomposes to PbCl 2 and Cl 2 . Analogously to lead monoxide , lead dioxide is capable of forming plumbate anions. Lead disulfide and lead diselenide are only stable at high pressures. Lead tetrafluoride , a yellow crystalline powder,
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#17328769432122024-404: Is a very soft metal with a Mohs hardness of 1.5; it can be scratched with a fingernail. It is quite malleable and somewhat ductile. The bulk modulus of lead—a measure of its ease of compressibility—is 45.8 GPa . In comparison, that of aluminium is 75.2 GPa; copper 137.8 GPa; and mild steel 160–169 GPa. Lead's tensile strength , at 12–17 MPa, is low (that of aluminium
2116-445: Is common for the carbon group. The divalent state is rare for carbon and silicon , minor for germanium, important (but not prevailing) for tin, and is the more important of the two oxidation states for lead. This is attributable to relativistic effects , specifically the inert pair effect , which manifests itself when there is a large difference in electronegativity between lead and oxide , halide , or nitride anions, leading to
2208-408: Is consistent with lead's atomic number being even. Lead has a magic number of protons (82), for which the nuclear shell model accurately predicts an especially stable nucleus. Lead-208 has 126 neutrons, another magic number, which may explain why lead-208 is extraordinarily stable. With its high atomic number, lead is the heaviest element whose natural isotopes are regarded as stable; lead-208
2300-414: Is exploited in the synthesis of other lead compounds. Few inorganic lead(IV) compounds are known. They are only formed in highly oxidizing solutions and do not normally exist under standard conditions. Lead(II) oxide gives a mixed oxide on further oxidation, Pb 3 O 4 . It is described as lead(II,IV) oxide , or structurally 2PbO·PbO 2 , and is the best-known mixed valence lead compound. Lead dioxide
2392-488: Is kept within Castleton where small articles, mainly jewellery, are worked and sold. A "lost" deposit was rediscovered in Treak Cliff Cavern in 2013, and in 2015 a new vein, the first for 150 years, was discovered close to the tourist route in the same cavern. Elsewhere, similar blue and white-yellow banded fluorite ornaments are now imported into the UK and other countries from China. Before they can be worked,
2484-502: Is more prevalent than most other elements with atomic numbers greater than 40. Primordial lead—which comprises the isotopes lead-204, lead-206, lead-207, and lead-208—was mostly created as a result of repetitive neutron capture processes occurring in stars. The two main modes of capture are the s- and r-processes . In the s-process (s is for "slow"), captures are separated by years or decades, allowing less stable nuclei to undergo beta decay . A stable thallium-203 nucleus can capture
2576-567: Is no reason to suppose the mineral came from Britain – Pliny and other writers specifically state that the mineral came from Persia . It is sometimes claimed that Blue John vases were found during excavations at Pompeii , but these vases are in fact made from banded amethystine quartz. However, two cups have been found among Roman grave-goods near the Turkish/Syrian border, on the former Persian-Roman trade route, which were made from blue-yellow banded fluorspar presumably obtained from
2668-650: Is not stable, as both the lead(III) ion and the larger complexes containing it are radicals . The same applies for lead(I), which can be found in such radical species. Numerous mixed lead(II,IV) oxides are known. When PbO 2 is heated in air, it becomes Pb 12 O 19 at 293 °C, Pb 12 O 17 at 351 °C, Pb 3 O 4 at 374 °C, and finally PbO at 605 °C. A further sesquioxide , Pb 2 O 3 , can be obtained at high pressure, along with several non-stoichiometric phases. Many of them show defective fluorite structures in which some oxygen atoms are replaced by vacancies: PbO can be considered as having such
2760-741: Is over three and a half times lower than that of the C–C bond . With itself, lead can build metal–metal bonds of an order up to three. With carbon, lead forms organolead compounds similar to, but generally less stable than, typical organic compounds (due to the Pb–C bond being rather weak). This makes the organometallic chemistry of lead far less wide-ranging than that of tin. Lead predominantly forms organolead(IV) compounds, even when starting with inorganic lead(II) reactants; very few organolead(II) compounds are known. The most well-characterized exceptions are Pb[CH(SiMe 3 ) 2 ] 2 and plumbocene . The lead analog of
2852-452: Is possible that Odin Mine does have Roman origins. The mine is not mentioned again in documents until 1663. In the early 18th century Richard Bagshawe, later to become High Sheriff of Derbyshire, had a considerable stake in the mine. The Bagshawe family retained their interests at Odin until the 1850s. The mine was worked continuously throughout the 18th century with annual ore extraction varying between 100 and 800 tonnes per annum. In April 1706
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2944-415: Is stable, but less so than the difluoride . Lead tetrachloride (a yellow oil) decomposes at room temperature, lead tetrabromide is less stable still, and the existence of lead tetraiodide is questionable. Some lead compounds exist in formal oxidation states other than +4 or +2. Lead(III) may be obtained, as an intermediate between lead(II) and lead(IV), in larger organolead complexes; this oxidation state
3036-413: Is still energetically favorable. Lead, like carbon, is predominantly tetravalent in such compounds. There is a relatively large difference in the electronegativity of lead(II) at 1.87 and lead(IV) at 2.33. This difference marks the reversal in the trend of increasing stability of the +4 oxidation state going down the carbon group; tin, by comparison, has values of 1.80 in the +2 oxidation state and 1.96 in
3128-636: Is the Deqing Fluorite Mine, in Deqing County , Zhejiang Province, the only source (other than in Derbyshire) that has an ornamental craft based upon it. However, although this fluorite is similar to Blue John its banding is straighter and it contains colours not associated with Blue John, suggesting they are compounds and not inclusions as in Blue John. Roman writers, such as Pliny the Elder , refer to
3220-448: Is the heaviest stable nucleus. (This distinction formerly fell to bismuth , with an atomic number of 83, until its only primordial isotope , bismuth-209, was found in 2003 to decay very slowly.) The four stable isotopes of lead could theoretically undergo alpha decay to isotopes of mercury with a release of energy, but this has not been observed for any of them; their predicted half-lives range from 10 to 10 years (at least 10 times
3312-481: Is the origin of the English word " plumbing ". Its ease of working, its low melting point enabling the easy fabrication of completely waterproof welded joints, and its resistance to corrosion ensured its widespread use in other applications, including pharmaceuticals, roofing, currency, warfare. Writers of the time, such as Cato the Elder , Columella , and Pliny the Elder , recommended lead (and lead-coated) vessels for
3404-525: Is the so-called inert pair effect : the 6s electrons of lead become reluctant to participate in bonding, stabilising the +2 oxidation state and making the distance between nearest atoms in crystalline lead unusually long. Lead's lighter carbon group congeners form stable or metastable allotropes with the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp orbitals. In lead,
3496-459: Is to us. Heinz Eschnauer and Markus Stoeppler "Wine—An enological specimen bank", 1992 Derbyshire Blue John Blue John (also known as Derbyshire Spar ) is a semi-precious mineral, a rare form of fluorite with bands of a purple-blue or yellowish colour. In the United Kingdom it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire . During
3588-446: Is usefully exploited: lead tetraacetate is an important laboratory reagent for oxidation in organic synthesis. Tetraethyllead, once added to automotive gasoline, was produced in larger quantities than any other organometallic compound, and is still widely used in fuel for small aircraft . Other organolead compounds are less chemically stable. For many organic compounds, a lead analog does not exist. Lead's per-particle abundance in
3680-732: The Ardennes region of Belgium; the Cave-in-Rock area of Illinois in the United States; and at various localities in Mexico and China. Blue-banded fluorite is very rare. An ornamental mineral known to the Romans as murrhine may have been a fluorspar similar to Blue John. Recently discovered deposits in China have produced fluorite with colouring and banding similar to the classic Blue John stone. One source
3772-589: The Common spotted orchid . Some plants called metallophytes can tolerate the high levels of metal in the soil: these include Spring Sandwort and Alpine Scurvy-grass . A gritstone crushing wheel, 1.75 metres in diameter with its iron tyre and circular iron track, used to crush the ore, can still be seen at the site. The crusher was built in 1823 at a cost of £40. Footnotes 53°20′54″N 1°48′06″W / 53.34823°N 1.80168°W / 53.34823; -1.80168 Lead Lead (pronounced "led")
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3864-608: The Phoenicians worked deposits in the Iberian peninsula ; by 1600 BC, lead mining existed in Cyprus , Greece , and Sardinia . Rome's territorial expansion in Europe and across the Mediterranean, and its development of mining, led to it becoming the greatest producer of lead during the classical era , with an estimated annual output peaking at 80,000 tonnes. Like their predecessors,
3956-659: The Solar System is 0.121 ppb (parts per billion). This figure is two and a half times higher than that of platinum , eight times more than mercury , and seventeen times more than gold . The amount of lead in the universe is slowly increasing as most heavier atoms (all of which are unstable) gradually decay to lead. The abundance of lead in the Solar System since its formation 4.5 billion years ago has increased by about 0.75%. The solar system abundances table shows that lead, despite its relatively high atomic number,
4048-795: The fall of Rome and did not reach comparable levels until the Industrial Revolution . Lead played a crucial role in the development of the printing press , as movable type could be relatively easily cast from lead alloys. In 2014, the annual global production of lead was about ten million tonnes, over half of which was from recycling. Lead's high density, low melting point, ductility and relative inertness to oxidation make it useful. These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction , plumbing , batteries , bullets , shots , weights , solders , pewters , fusible alloys , lead paints , leaded gasoline , and radiation shielding . Lead
4140-401: The nucleus , and more shielded by smaller orbitals. The sum of the first four ionization energies of lead exceeds that of tin, contrary to what periodic trends would predict. This is explained by relativistic effects , which become significant in heavier atoms, which contract s and p orbitals such that lead's 6s electrons have larger binding energies than its 5s electrons. A consequence
4232-468: The +4 state. Lead(II) compounds are characteristic of the inorganic chemistry of lead. Even strong oxidizing agents like fluorine and chlorine react with lead to give only PbF 2 and PbCl 2 . Lead(II) ions are usually colorless in solution, and partially hydrolyze to form Pb(OH) and finally [Pb 4 (OH) 4 ] (in which the hydroxyl ions act as bridging ligands ), but are not reducing agents as tin(II) ions are. Techniques for identifying
4324-414: The 19th century Blue John was being fashioned into a wide variety of ornamental items ranging from knife-handles to chalices. The precise quantities mined in any given year are unknown, but 18th-century leases restricted output to 20 tons per annum. By 1892, the output is said to have been limited to 3 tons per annum. Today, production is probably around half a ton per annum, and the raw Blue John produced
4416-485: The 19th century, it was mined for its ornamental value, and mining continues on a small scale. The most common explanation for the name is that it derives from the French bleu-jaune , meaning 'blue-yellow'. The story goes that Blue John was exported to France where it was used by ormolu workers during the reign of Louis XVI (1774–92). However, there is no archival record of any Blue John being exported to France, and
4508-671: The Blue John to create decorative vases. It is known that by this date the mining of Blue John had been going on for several years. The earliest dated decorative applications of Blue John in Britain are those in use as fireplace panels. The bridal suite of the Friary Hotel in Derby has a Blue John plaque dated to around 1760. About the same time, fireplaces with Blue John panels were designed by neoclassical architect and interior designer Robert Adam , and put in place at Kedleston Hall near Derby. By
4600-760: The Castleton Site of Special Scientific Interest . The origins of Odin Mine are unclear; many Peak District guidebooks and sources say that the mine was first worked by the Romans and subsequently by the Saxons and the Danes . Trevor D. Ford states "It was probably worked in Roman times, again in the Dark Ages and in Norman times". However, there is no historical evidence to back this up. The use of
4692-627: The Derbyshire lead mines in the 1740s. The name "Blue John" is used for several rocks in Cornwall , including fluorspars, and derives from the Cornish language word bleujenn , in Old Cornish blodon , a flower, bloom or blossom. In the United Kingdom, the blue, banded fluorite known as Blue John is found only under the triangular hill known as Treak Cliff, just outside the village of Castleton . Today
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#17328769432124784-606: The Egyptians had used lead for sinkers in fishing nets , glazes , glasses , enamels , ornaments . Various civilizations of the Fertile Crescent used lead as a writing material , as coins , and as a construction material . Lead was used by the ancient Chinese as a stimulant , as currency , as contraceptive , and in chopsticks . The Indus Valley civilization and the Mesoamericans used it for making amulets ; and
4876-728: The Persian source mentioned by Pliny. Both cups, known as the Crawford Cup and the Barber Cup , are in the British Museum . It is sometimes said that Blue John of Derbyshire was discovered by the Romans. However, the earliest source of this story is William Adam's 1843 book Gem of the Peak . It seems likely that Adam was attempting to add some mystique to the Derbyshire Blue John. Although
4968-428: The Romans did mine lead in Derbyshire, there is no evidence that they encountered the Blue John veins. The earliest reference to the mineral "Blue John" occurs in a letter dated 1766 noting a lease from Lady Mazarine, which states that she "let ye Blue John, Castleton". The next reference occurs in a 1768 letter by the industrialist Matthew Boulton who attempted to purchase or lease the mines so that he could mine
5060-422: The Romans obtained lead mostly as a by-product of silver smelting. Lead mining occurred in central Europe , Britain , Balkans , Greece , Anatolia , Hispania , the latter accounting for 40% of world production. Lead tablets were commonly used as a material for letters. Lead coffins, cast in flat sand forms and with interchangeable motifs to suit the faith of the deceased, were used in ancient Judea . Lead
5152-600: The atmosphere; 100 mg/kg in soil; 4 mg/kg in vegetation, 5 μg/L in fresh water and seawater. The modern English word lead is of Germanic origin; it comes from the Middle English leed and Old English lēad (with the macron above the "e" signifying that the vowel sound of that letter is long). The Old English word is derived from the hypothetical reconstructed Proto-Germanic * lauda- ('lead'). According to linguistic theory, this word bore descendants in multiple Germanic languages of exactly
5244-485: The course of the Earth's history, have remained in the crust instead of sinking deeper into the Earth's interior. This accounts for lead's relatively high crustal abundance of 14 ppm; it is the 36th most abundant element in the crust. The main lead-bearing mineral is galena (PbS), which is mostly found with zinc ores. Most other lead minerals are related to galena in some way; boulangerite , Pb 5 Sb 4 S 11 ,
5336-419: The current age of the universe). Three of the stable isotopes are found in three of the four major decay chains : lead-206, lead-207, and lead-208 are the final decay products of uranium-238 , uranium-235 , and thorium-232 , respectively. These decay chains are called the uranium chain , the actinium chain , and the thorium chain . Their isotopic concentrations in a natural rock sample depends greatly on
5428-428: The diiodide . Many lead(II) pseudohalides are known, such as the cyanide, cyanate, and thiocyanate . Lead(II) forms an extensive variety of halide coordination complexes , such as [PbCl 4 ] , [PbCl 6 ] , and the [Pb 2 Cl 9 ] n chain anion. Lead(II) sulfate is insoluble in water, like the sulfates of other heavy divalent cations . Lead(II) nitrate and lead(II) acetate are very soluble, and this
5520-428: The early ormolu ornaments which use Blue John were being manufactured by Matthew Boulton of Birmingham in the 1760s. An alternative origin of the name derives from an old miners' name for the zinc ore sphalerite , which they called "Black Jack". Thus, the unique blue stone mined in these caverns could easily have become known as "Blue John". Another derivation comes from the Cornish miners who began working
5612-515: The eastern and southern Africans used lead in wire drawing . Because silver was extensively used as a decorative material and an exchange medium, lead deposits came to be worked in Asia Minor from 3000 BC; later, lead deposits were developed in the Aegean and Laurion . These three regions collectively dominated production of mined lead until c. 1200 BC . Beginning c. 2000 BC,
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#17328769432125704-566: The element its chemical symbol Pb . The word * ɸloud-io- is thought to be the origin of Proto-Germanic * bliwa- (which also means 'lead'), from which stemmed the German Blei . The name of the chemical element is not related to the verb of the same spelling, which is derived from Proto-Germanic * laidijan- ('to lead'). Metallic lead beads dating back to 7000–6500 BC have been found in Asia Minor and may represent
5796-418: The entrance to Odin Mine. In the early days before explosives, the rock was weakened by fire setting: this involved heating the rock overnight by leaving fires lit and then cooling the rock with water the next morning causing the rock to shatter. The Romans had great need for lead, especially for the plumbing systems in their dwellings. They mined the ore galena extensively during their time in Britain, so it
5888-413: The first example of metal smelting . At that time, lead had few (if any) applications due to its softness and dull appearance. The major reason for the spread of lead production was its association with silver, which may be obtained by burning galena (a common lead mineral). The Ancient Egyptians were the first to use lead minerals in cosmetics, an application that spread to Ancient Greece and beyond;
5980-430: The group. Lead dihalides are well-characterized; this includes the diastatide and mixed halides, such as PbFCl. The relative insolubility of the latter forms a useful basis for the gravimetric determination of fluorine. The difluoride was the first solid ionically conducting compound to be discovered (in 1834, by Michael Faraday ). The other dihalides decompose on exposure to ultraviolet or visible light, especially
6072-446: The inert pair effect increases the separation between its s- and p-orbitals, and the gap cannot be overcome by the energy that would be released by extra bonds following hybridization. Rather than having a diamond cubic structure, lead forms metallic bonds in which only the p-electrons are delocalized and shared between the Pb ions. Lead consequently has a face-centered cubic structure like
6164-447: The late 19th century AD. A lead atom has 82 electrons , arranged in an electron configuration of [ Xe ]4f 5d 6s 6p . The sum of lead's first and second ionization energies —the total energy required to remove the two 6p electrons—is close to that of tin , lead's upper neighbor in the carbon group . This is unusual; ionization energies generally fall going down a group, as an element's outer electrons become more distant from
6256-560: The latter being stable only above around 488 °C. Litharge is the most commonly used inorganic compound of lead. There is no lead(II) hydroxide; increasing the pH of solutions of lead(II) salts leads to hydrolysis and condensation. Lead commonly reacts with heavier chalcogens. Lead sulfide is a semiconductor , a photoconductor , and an extremely sensitive infrared radiation detector . The other two chalcogenides, lead selenide and lead telluride , are likewise photoconducting. They are unusual in that their color becomes lighter going down
6348-441: The latter is not; this allows for lead–lead dating . As uranium decays into lead, their relative amounts change; this is the basis for uranium–lead dating . Lead-207 exhibits nuclear magnetic resonance , a property that has been used to study its compounds in solution and solid state, including in the human body. Apart from the stable isotopes, which make up almost all lead that exists naturally, there are trace quantities of
6440-456: The lighter members of the group, lead tends to bond with itself ; it can form chains and polyhedral structures. Since lead is easily extracted from its ores , prehistoric people in the Near East were aware of it . Galena is a principal ore of lead which often bears silver. Interest in silver helped initiate widespread extraction and use of lead in ancient Rome . Lead production declined after
6532-567: The mine in September 1856, handing over ownership to Robert How Ashton of Losehill Hall . Lead production at the mine stopped in 1869, although some working took place in 1908 and 1909 when considerable amounts of fluorspar and barite were excavated from the Mam Engine Shaft. The veins of lead in the Castleton area formed 280 million years ago when a fault in the local Carboniferous limestone allowed mineralising fluids to flow into fissures in
6624-517: The mine; the most prominent of these is Odin Cave (called Gank Hole by the miners) which was formed by groundwater opening out a void between limestone boulders. There is no evidence that Blue John was ever mined at Odin although the adjacent Treak Cliff Cavern regularly mines the rock in areas not open to visitors. The site of Odin Mine is owned by the National Trust . It consists of a limestone gorge,
6716-484: The name “Odin” is often cited as evidence that the mine was named by the Danes after their chief god. This is backed up by evidence that prior to the 19th century the mine was commonly called Oden in mining records, which is more in common with the traditional Danish spelling. The first mention of the mine in official records was in 1280 when a poacher John of Bellhag was put on trial for hunting at Bactor Wood in Castleton and at
6808-533: The neutrons are arranged in complete shells in the atomic nucleus, and it becomes harder to energetically accommodate more of them. When the neutron flux subsides, these nuclei beta decay into stable isotopes of osmium , iridium , platinum . Lead is classified as a chalcophile under the Goldschmidt classification , meaning it is generally found combined with sulfur. It rarely occurs in its native , metallic form. Many lead minerals are relatively light and, over
6900-497: The north to keep the workings dry. Later the miners followed the vein of lead underground. The vein is exposed on the surface in a small limestone outcrop at the entrance to the mine and then continues underground just south of due west in the limestone under the Edale shales of Mam Tor. The 1769 plans of the mine show that there were several branch veins leading from the main lead workings. There are several small pipe caverns contained within
6992-438: The original early workings before they went underground to follow the veins of ore. It looks like a natural limestone ravine with the workings now disguised by natural vegetation. To the left of the gorge is the two-metre-wide Odin Cave, which goes about 10 metres underground. The remaining spoil heaps are a protected archaeological site and support a wide variety of plants including Birdsfoot Trefoil , Eyebright , Wild thyme and
7084-436: The piece is returned to the lathe and polished with wet abrasive paper. A final high polish is added using putty powder (finely crushed tin dioxide ) applied with a moist piece of felt. For making jewellery, thin slices are marked out and cut into shapes such as circles or ovals, then finished on a grinding wheel. The rear faces of single-sided pieces are painted white before they are mounted. " The Terror of Blue John Gap "
7176-418: The preparation of sweeteners and preservatives added to wine and food. The lead conferred an agreeable taste due to the formation of "sugar of lead" ( lead(II) acetate ), whereas copper vessels imparted a bitter flavor through verdigris formation. This metal was by far the most used material in classical antiquity, and it is appropriate to refer to the (Roman) Lead Age. Lead was to the Romans what plastic
7268-414: The presence of the Pb ion in water generally rely on the precipitation of lead(II) chloride using dilute hydrochloric acid. As the chloride salt is sparingly soluble in water, in very dilute solutions the precipitation of lead(II) sulfide is instead achieved by bubbling hydrogen sulfide through the solution. Lead monoxide exists in two polymorphs , litharge α-PbO (red) and massicot β-PbO (yellow),
7360-422: The presence of these three parent uranium and thorium isotopes. For example, the relative abundance of lead-208 can range from 52% in normal samples to 90% in thorium ores; for this reason, the standard atomic weight of lead is given to only one decimal place. As time passes, the ratio of lead-206 and lead-207 to lead-204 increases, since the former two are supplemented by radioactive decay of heavier elements while
7452-432: The r-process (r is for "rapid"), captures happen faster than nuclei can decay. This occurs in environments with a high neutron density, such as a supernova or the merger of two neutron stars . The neutron flux involved may be on the order of 10 neutrons per square centimeter per second. The r-process does not form as much lead as the s-process. It tends to stop once neutron-rich nuclei reach 126 neutrons. At this point,
7544-541: The resulting chloride layer diminishes the reactivity of the elements. Molten lead reacts with the chalcogens to give lead(II) chalcogenides. Lead metal resists sulfuric and phosphoric acid but not hydrochloric or nitric acid ; the outcome depends on insolubility and subsequent passivation of the product salt. Organic acids, such as acetic acid , dissolve lead in the presence of oxygen. Concentrated alkalis dissolve lead and form plumbites . Lead shows two main oxidation states: +4 and +2. The tetravalent state
7636-406: The rock, pushed up by great pressure from beneath the Earth's surface. Lead and sulphate combined to form the lead ore galena . In its heyday, the mine was a complex system of levels and shafts that extended for approximately 1500 metres into the Edale shales beneath the nearby Mam Tor. In the early days the mining was open cast, forming a gorge in the hillside with the water diverted by a leat to
7728-507: The same meaning. There is no consensus on the origin of the Proto-Germanic * lauda- . One hypothesis suggests it is derived from Proto-Indo-European * lAudh- ('lead'; capitalization of the vowel is equivalent to the macron). Another hypothesis suggests it is borrowed from Proto-Celtic * ɸloud-io- ('lead'). This word is related to the Latin plumbum , which gave
7820-491: The similarly sized divalent metals calcium and strontium . Pure lead has a bright, shiny gray appearance with a hint of blue. It tarnishes on contact with moist air and takes on a dull appearance, the hue of which depends on the prevailing conditions. Characteristic properties of lead include high density , malleability, ductility, and high resistance to corrosion due to passivation . Lead's close-packed face-centered cubic structure and high atomic weight result in
7912-588: The simplest organic compound , methane , is plumbane . Plumbane may be obtained in a reaction between metallic lead and atomic hydrogen. Two simple derivatives, tetramethyllead and tetraethyllead , are the best-known organolead compounds. These compounds are relatively stable: tetraethyllead only starts to decompose if heated or if exposed to sunlight or ultraviolet light. With sodium metal, lead readily forms an equimolar alloy that reacts with alkyl halides to form organometallic compounds such as tetraethyllead. The oxidizing nature of many organolead compounds
8004-410: The stones (having been air-dried for at least a year) are heated in an oven, then placed in a bowl of hot epoxy resin (previously, pine resin was used), and then further heated in a vacuum oven. This drives out air from minute pores in the stone, and replaces it with the resin, which binds the otherwise friable crystal structure, allowing it to be cut and polished. After resining, the stones are cut on
8096-601: The veins are mined only in Blue John Cavern and the nearby Treak Cliff Cavern , although the abandoned Old Tor Mine on the north side of Winnats Pass was also, at one time, a source for the mineral. The mineral veins of the Peak District were formed during the late Carboniferous and Early Permian times, when the limestones were at a depth of 3 kilometres (1.9 mi). The minerals were deposited in veins by layers of crystals precipitating from hot fluids coating
8188-403: The very rare cluster decay of radium-223, one of the daughter products of natural uranium-235, and the decay chain of neptunium-237, traces of which are produced by neutron capture in uranium ores. Lead-213 also occurs in the decay chain of neptunium-237. Lead-210 is particularly useful for helping to identify the ages of samples by measuring its ratio to lead-206 (both isotopes are present in
8280-531: The walls of fractures, caves, and other cavities. Petrological analysis has shown that the Blue John, like fluorite elsewhere in the Peak District, crystallised from a highly saline fluid at temperatures of 90–120 °C or perhaps a little higher. Despite much investigation, the origin of the blue colour of Blue John remains uncertain. Microscopic analysis has failed to find any impurities such as potassium permanganate or hydrocarbons which could produce
8372-511: The workings. The mine produced extensive spoil and this was used by the Manchester and Sheffield Turnpike company in 1802 when constructing a new road between the two places. The spoil contained fluorspar , calcite , and barite which was extracted in later years when their value became known. There was a gap in production between 1848 and 1852 and the Bagshawe family withdrew their interests from
8464-522: Was used to make sling bullets from the 5th century BC. In Roman times, lead sling bullets were amply used, and were effective at a distance of between 100 and 150 meters. The Balearic slingers , used as mercenaries in Carthaginian and Roman armies, were famous for their shooting distance and accuracy. Lead was used for making water pipes in the Roman Empire ; the Latin word for the metal, plumbum ,
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