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Copper(I) Sulfide
Copper(I) sulfide is a copper sulfide, a chemical compound of copper and sulfur. It has the chemical compound Cu2S. It is found in nature as the mineral chalcocite. It has a narrow range of stoichiometry ranging from Cu1.997S to Cu2.000S. Samples are typically black. Preparation and reactions Cu2S can be prepared by treating copper with sulfur or H2S. The rate depends on the particle size and temperature. Cu2S reacts with oxygen to form SO2:Wiberg, Egon and Holleman, Arnold Frederick (2001) ''Inorganic Chemistry'', Elsevier : The production of copper from chalcocite is a typical process in extracting the metal from ores. Usually, the conversion involves roasting, to give Cu2O and sulfur dioxide: : Copper (I) oxide oxide readily converts to copper (II) oxide when heated in the presence of oxygen, and to copper metal upon heating in a reducing environment. (cf. Carbothermic reduction) Structure Stoichiometric Two forms ( a dimorphism) of Cu2S are known. The so-called l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcocite
Chalcocite (), copper(I) sulfide (Cu2S), is an important copper ore mineral. It is opaque and dark gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohs scale. It is a sulfide with a monoclinic crystal system. The term ''chalcocite'' from the Greek ''khalkos'', meaning "copper". It is also known as redruthite, vitreous copper, or copper-glance. Occurrence Chalcocite is sometimes found as a primary vein mineral in hydrothermal veins. However, most chalcocite occurs in the supergene enriched environment below the oxidation zone of copper deposits as a result of the leaching of copper from the oxidized minerals. It is also often found in sedimentary rocks. It has been mined for centuries and is one of the most profitable copper ores. The reasons for this is its high copper content (66.7% atomic ratio and nearly 80% by weight) and the ease at which copper can be separated from sulfur. Since chalcocite is a secondary mineral that forms from the al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbothermic Reduction
Carbothermic reactions involve the reduction of substances, often metal oxides (O2-), using carbon (C) as the reducing agent. The reduction is usually conducted in the electric arc furnace or reverberatory furnace, depending on the metal ore. These chemical reactions are usually conducted at temperatures of several hundred degrees Celsius. Such processes are applied for production of the elemental forms of many elements. The ability of metals to participate in carbothermic reactions can be predicted from Ellingham diagrams. Carbothermal reactions produce carbon monoxide (CO) and sometimes carbon dioxide (CO2). The facility of these conversions is attributable to the entropy of reaction: two solids, the metal oxide (and flux) and carbon, are converted to a new solid (metal) and a gas (CO), the latter having high entropy. Applications A prominent example is that of iron ore smelting. Many reactions are involved, but the simplified equation is usually shown as: : 2 + 3 C → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide Minerals
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide () as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts.http://www.minerals.net/mineral/sort-met.hod/group/sulfgrp.htm Minerals.net Dana Classification, SulfidesKlein, Cornelis and Cornelius S. Hurlbut, Jr., 1986, ''Manual of Mineralogy'', Wiley, 20th ed., pp 269-293 Sulfide minerals are inorganic compounds. Minerals Common or important examples include: * Acanthite * Chalcocite * Bornite *Galena *Sphalerite *Chalcopyrite *Pyrrhotite * Millerite *Pentlandite * Covellite *Cinnabar * Realgar *Orpiment * Stibnite *Pyrite * Marcasite * Molybdenite Sulfarsenides: * Cobaltite * Arsenopyrite * Gersdorffite Sulfosalts: * Pyrargyrite * Proustite * Tetrahedrite * Tennantite * Enargite * B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LK-99
LK-99 also called PCPOSOS, is a gray–black, polycrystalline compound, identified as a copper- doped lead‒oxyapatite. A team from Korea University led by Lee Sukbae () and Kim Ji-Hoon () began studying this material as a potential superconductor, and in July 2023 published preprints claiming that it acted as a room-temperature superconductor at temperatures of up to at ambient pressure. Many different researchers attempted to replicate the work, and were able to reach initial results within weeks, as the process of producing the material is relatively straightforward. By mid-August 2023, the consensus was that LK-99 is not a superconductor at room temperature, and is an insulator in pure form. As of 12 February 2024, no replications had gone through the peer review process of a journal, but some had been reviewed by a materials science lab. A number of replication attempts identified non-superconducting ferromagnetic and diamagnetic causes for observations that suggeste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Djurleite
Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with other supergene minerals such as chalcocite, covellite and digenite in the enriched zone of copper orebodies. It is a member of the chalcocite group, and very similar to chalcocite, Cu2S, in its composition and properties, but the two minerals can be distinguished from each other by x-ray powder diffraction. Intergrowths and transformations between djurleite, digenite and chalcocite are common.Pósfai, M. & Buseck, P. R. (1994): Djurleite, digenite, and chalcocite: Intergrowths and transformations. American Mineralogist, 79, 308-315 Many of the reported associations of digenite and djurleite, however, identified by powder diffraction, could be anilite and djurleite, as anilite transforms to digenite during grinding. Djurleite was name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Monosulfide
Copper monosulfide is a chemical compound of copper and sulfur. It was initially thought to occur in nature as the dark indigo blue mineral covellite. However, it was later shown to be rather a cuprous compound, formula .Liang, W., Whangbo, M.H. (1993) ''Conductivity anisotropy and structural phase transition in Covellite CuS'' Solid State Communications, 85(5), 405-408 CuS is a moderate conductor of electricity.Wells A.F. (1962) ''Structural Inorganic Chemistry'' 3d edition Oxford University Press A black colloidal precipitate of CuS is formed when hydrogen sulfide, H2S, is bubbled through solutions of Cu(II) salts. It is one of a number of binary compounds of copper and sulfur (see copper sulfide for an overview of this subject), and has attracted interest because of its potential uses in catalysis and photovoltaics. Manufacturing Copper monosulfide can be prepared by passing hydrogen sulfide gas into a solution of copper(II) salt. Alternatively, it can be prepared by meltin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Sulfide
Copper sulfides describe a family of chemical compounds and minerals with the formula CuxSy. Both minerals and synthetic materials comprise these compounds. Some copper sulfides are economically important ores. Prominent copper sulfide minerals include Cu2S ( 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. Known copper sulfides The naturally occurring mineral binary compounds of copper and sulfur are listed below. Investigations of covellite ( CuS) indicate that there are other metastable Cu-S phases still to be fully characterised. * CuS2, villamaniniteWells A.F. (1984) ''Structural Inorganic C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2308
In contemporary history, the third millennium is the current millennium in the ''Anno Domini'' or Common Era, under the Gregorian calendar. It began on 1 January 2001 ( MMI) and will end on 31 December 3000 ( MMM), spanning the 21st to 30th centuries. Ongoing futures studies seek to understand what will likely continue and what could plausibly change in this period and beyond. Predictions and forecasts not included on this timeline * Climate change * Extinction * List of dates predicted for apocalyptic events * List of future astronomical events ** List of lunar eclipses in the 21st century ** List of solar eclipses in the 21st century * List of time capsules * Near future centennial (bi, tri, etc.) events. * Near future in fiction * Predictions and claims for the Second Coming * Projections of population growth ** Representative Concentration Pathway ** Shared Socioeconomic Pathways 21st century 2000s * See: 2000 * 2001 * 2002 * 2003 * 2004 * 2005 * 2006 * 2007 * 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistivity
Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of either a positive or negative electric charge produces an electric field. The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the work done to move an electric charge from one point to another within an electric field, typically measured in volts. Electricity plays a central role in many modern technologies, serving in electric power where electric current is used to energise equipment, and in electronics dealing wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-stoichiometric
Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having chemical element, elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); most often, in such materials, some small percentage of atoms are missing or too many atoms are packed into an otherwise perfect Crystal structure, lattice work. Contrary to earlier definitions, modern understanding of non-stoichiometric compounds view them as homogeneous, and not mixtures of stoichiometric chemical compounds. Since the solids are overall electrically neutral, the defect is compensated by a change in the charge of other atoms in the solid, either by changing their oxidation state, or by replacing them with atoms of different elements with a different charge. Many metal oxides and sulfides have non-stoichiometric examples; for example, stoichiometric iron(II) oxide, which is rare, has the formula , whereas the more common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Djurleite
Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with other supergene minerals such as chalcocite, covellite and digenite in the enriched zone of copper orebodies. It is a member of the chalcocite group, and very similar to chalcocite, Cu2S, in its composition and properties, but the two minerals can be distinguished from each other by x-ray powder diffraction. Intergrowths and transformations between djurleite, digenite and chalcocite are common.Pósfai, M. & Buseck, P. R. (1994): Djurleite, digenite, and chalcocite: Intergrowths and transformations. American Mineralogist, 79, 308-315 Many of the reported associations of digenite and djurleite, however, identified by powder diffraction, could be anilite and djurleite, as anilite transforms to digenite during grinding. Djurleite was name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexagonal Close Packed
In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occupied by spheres – that can be achieved by a lattice packing is :\frac \approx 0.74048. The same packing density can also be achieved by alternate stackings of the same close-packed planes of spheres, including structures that are aperiodic in the stacking direction. The Kepler conjecture states that this is the highest density that can be achieved by any arrangement of spheres, either regular or irregular. This conjecture was proven by Thomas Hales. The highest density is so far known only for 1, 2, 3, 8, and 24 dimensions. Many crystal structures are based on a close-packing of a single kind of atom, or a close-packing of large ions with smaller ions filling the spaces between them. The cubic and hexagonal arrangements are very cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
