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Tellurium
Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth.Anderson, Don L.; "Chemical Composition of the Mantle" in ''Theory of the Earth'', pp. 147-175 Tellurium-bearing compounds were first discovered in 1782 in a gold mine in Kleinschlatten, Transylvania (now Zlatna, Romania) by Austrian mineralogist Franz-Joseph Müller von Reichenstein, although it was Martin Heinrich Klaproth who named the new element in 1798 after the Latin 'earth'. Gold telluride minerals ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metalloid
A metalloid is a type of chemical element which has a preponderance of material property, properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine. On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include a dividing line between metals and nonmetals, and the metalloids may be found close to this line. Typical metalloids have a metallic appearance, but they are brittle and only fair electrical conductor, conductors of electricity. Chemica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcogen
The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" is derived from a combination of the Greek word () principally meaning copper (the term was also used for bronze/brass, any metal in the poetic sense, ore or coin), and the Latinized Greek word , meaning ''born'' or ''produced''. Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century. Selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. All of the chalcogens h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurium Copper
Tellurium copper is an alloy of copper and tellurium. Tellurium improves the machinability of copper. Overview Tellurium is usually added to copper to improve machinability ("free cutting"). ASTM specification B301 has 0.5% tellurium; at concentrations of up to 0.75% machinability is improved while electrical conductivity and hot working behavior is maintained. Mechanical properties are similar to ''tough pitch copper'', while machinability is similar to brass - the hardness of the alloy is increased by precipitation of the copper telluride: weissite. Tellurium copper is not suited to welding, but it can be welded with gas shielded arc welding or resistance welding. It can be readily soft soldered, silver soldered, or brazed. Tellurium copper can be used as the electrode in electrical discharge machining (EDM) - the alloy is used to replace copper when grinding wheel Grinding wheels contains abrasive compounds for grinding and abrasive machining operations. Such wheels are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CdTe Solar Panel
Cadmium telluride (CdTe) photovoltaics is a photovoltaic (PV) technology based on the use of cadmium telluride in a thin semiconductor layer designed to absorb and convert sunlight into electricity. Cadmium telluride PV is the only thin film technology with lower costs than conventional solar cells made of crystalline silicon in multi-kilowatt systems.K. Zweibel, J. Mason, V. Fthenakis,A Solar Grand Plan, ''Scientific American'', Jan 2008. CdTe PV is the cheapest example of PV technologies and prices are about 16¢/kWh with US Southwest sunlight. , on a lifecycle basis, CdTe PV has the smallest carbon footprint, lowest water use and shortest energy payback time of any current photo voltaic technology. CdTe's energy payback time of less than a year allows for faster carbon reductions without short-term energy deficits. The toxicity of cadmium is an environmental concern during production and when the panels are disposed of. Some of this might be mitigated by recycling of CdT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It seldom occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium – from Greek ( 'Moon') – was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Telluride
Dimethyl telluride is an organotelluride compound, formula ( CH3)2 Te, also known by the abbreviation DMTe. This was the first material used to grow epitaxial cadmium telluride and mercury cadmium telluride using metalorganic vapour phase epitaxy. Dimethyl telluride as a product of microbial metabolism was first discovered in 1939. It is produced by some fungi and bacteria (''Penicillium brevicaule'', ''P. chrysogenum'', and '' P. notatum'' and the bacterium ''Pseudomonas fluorescens''). The toxicity of DMTe is unclear. It is produced by the body when tellurium or one of its compounds are ingested. It is noticeable by the garlic smelling breath it gives those exposed, similar to the effect of DMSO. Tellurium is known to be toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst .... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allotrope
Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element: the atoms of the element are bonded together in a different manner. For example, the allotropes of carbon include diamond (the carbon atoms are bonded together to form a cubic lattice of tetrahedra), graphite (the carbon atoms are bonded together in sheets of a hexagonal lattice), graphene (single sheets of graphite), and fullerenes (the carbon atoms are bonded together in spherical, tubular, or ellipsoidal formations). The term ''allotropy'' is used for elements only, not for compounds. The more general term, used for any compound, is polymorphism, although its use is usually restricted to solid materials such as crystals. Allotropy refers only to different forms of an element within the same physical phase (the state of matter, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franz-Joseph Müller Von Reichenstein
Franz-Joseph Müller, Freiherr von Reichenstein or Franz-Joseph Müller von Reichenstein (1 July 1740 or 4 October 1742 – 12 October 1825 or 1826) was an Austrian mineralogist and mining engineer. Müller held several positions in the Habsburg monarchy administration of mines and coinage in the Banat, Transylvania, and Tyrol. During his time in Transylvania he discovered tellurium in 1782. In his later career he became a member of the imperial council in Vienna and was knighted and elevated to the rank Freiherr in 1820. Place and date of birth Müller was born in 1740 or 1742 in the Habsburg Empire. While the ''Allgemeine Deutsche Biographie'' gives 1 July 1740 and Vienna as date and place of birth, the ''Neue Deutsche Biographie'' prefers 4 October 1742 and the small town of Poysdorf in Lower Austria. The much older works ''Neuer Nekrolog der Deutschen'' and ''Oesterreichische National-Encyklopädie'' do not give a place of birth and only the year 1740 for his birth. Even articl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abundance Of The Chemical Elements
The abundance of the chemical elements is a measure of the Type–token distinction#Occurrences, occurrence of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by the mass fraction (chemistry), mass-fraction (the same as weight fraction); by the mole fraction, mole-fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases); or by the volume fraction, volume-fraction. Volume-fraction is a common abundance measure in mixed gases such as planetary atmospheres, and is similar in value to molecular mole-fraction for gas mixtures at relatively low densities and pressures, and ideal gas mixtures. Most abundance values in this article are given as mass-fractions. For example, the abundance of oxygen in pure water can be measured in two ways: the ''mass fraction'' is about 89%, because that is the fraction of water's mass which is oxygen. However, the ''mole-fraction'' is about 33% becau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zlatna
Zlatna (german: Klein-Schlatten, Kleinschlatten, Goldenmarkt; hu, Zalatna; la, Ampellum) is a town in Alba County, central Transylvania, Romania. It has a population of 7,490. Administration The town administers eighteen villages: Botești (''Golddorf''; ''Botesbánya''), Budeni (''Higendorf''), Dealu Roatei (''Rotberg''), Dobrot, Dumbrava, Feneș (''Wildendorf''; ''Fenes''), Galați (''Galz''; ''Ompolygalac''), Izvoru Ampoiului (''Gross-Ompeil''; ''Nagyompoly''), Pârău Gruiului (''Gruybach''), Pătrângeni (''Peters''; ''Ompolykövesd ''), Pirita (''Pfirth''), Podu lui Paul (''Pauls''), Runc (''Goldrücken''), Ruși (''Rusch''), Suseni (''Oberdorf''), Trâmpoiele (''Trempojel''; ''Kénesd''), Valea Mică (''Kleinwasser'') and Vâltori (''Waldrücken''; ''Vultur''). Geography Zlatna is located north-west of the county seat, Alba Iulia, on the border with Hunedoara County. Situated in the Zlatna depression, between the Metaliferi Mountains and the Trascău Mountains, the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurocysteine
Tellurocysteine (in some publications referred to as Te-Cys) is an amino acid analogous to serine, cysteine and selenocysteine with tellurium in place of oxygen, sulfur or selenium in its side chain. It is not naturally found in organisms. Properties Perhaps due to its low bond energy with carbon (200 kJ/mol compared to 234 kJ/mol for selenium, or 272 kJ/mol for sulfur), tellurocysteine is not present in any known natural organisms and is hence relatively understudied in comparison to selenocysteine. Despite so, certain organisms such as fungi ''Aspergillus fumigatus'' is capable of incorporating tellurocysteine and telluromethionine into amino acids and proteins when exposed to a sulfur-free environment. It has been observed that when incorporated into glutathione transferase, tellurocysteine efficiently inhibited aminoacylation and increased the efficiency of glutathione peroxidase. Synthesis L-Tellurocysteine has been prepared from elemental tellurium by first reacting it wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technology-critical Element
A technology-critical element (TCE) is a chemical element that is critical to modern and emerging technologies. Technology-critical elements are elements for which a striking acceleration in usage has emerged, relative to past consumption. Many advanced engineering applications, such as clean-energy production, communications and computing, use emergent technologies that utilize numerous chemical elements. Other similar terms used in literature include: critical elements, critical materials, critical raw materials, energy critical elements and elements of security. In 2013, the U.S. Department of Energy (DOE) created the Critical Materials Institute (CMI) to address the issue. In 2015, the European COST Action TD1407 created a network of scientists working and interested on TCEs, from an environmental perspective to potential human health threats. A study estimated losses of 61 metals to help the development of circular economy strategies, showing that usespans of, often scarce, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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