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Cobalt Disilicide
Cobalt disilicide (CoSi2) is an intermetallic compound, a silicide of cobalt. It is a superconductor with a transition temperature of around 1.4 K and a critical field For a given temperature, the critical field refers to the maximum magnetic field strength below which a material remains superconducting. Superconductivity is characterized both by perfect conductivity (zero resistance) and by the complete expulsio ... of 105 Oe.Haynes, p. 12.70 References Cited sources * {{Silicides Cobalt compounds Transition metal silicides Fluorite crystal structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Symbol
The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure, and was originated by W. B. Pearson. The symbol is made up of two letters followed by a number. For example: * Diamond structure, ''cF''8 * Rutile structure, ''tP''6 The two (italicised) letters specify the Bravais lattice. The lower-case letter specifies the crystal family, and the upper-case letter the centering type. The number at the end of the Pearson symbol gives the number of the atoms in the conventional unit cell.Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005 IR-3.4.4, pp. 49–51; IR-11.5, pp. 241–242. |
Iron Disilicide
Iron disilicide (FeSi2) is an intermetallic compound, a silicide of iron that occurs in nature as the rare mineral linzhiite. At room temperature it forms orthorhombic crystals (β phase), which convert into a tetragonal α phase upon heating to 970 °C. See also *Ferrosilicon Ferrosilicon is an alloy of iron and silicon with a typical silicon content by weight of 15–90%. It contains a high proportion of iron silicides. Production and reactions Ferrosilicon is produced by reduction of silica or sand with coke in t ... References {{Silicides Iron compounds Transition metal silicides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese Disilicide
Manganese disilicide (MnSi2) is an intermetallic compound, a silicide of manganese. It is a non-stoichiometric compound, with a silicon deficiency expressed as MnSi2–x. Crystal structures of many MnSi2–x compounds resemble a chimney ladder and are called Nowotny phases. They include MnSi2 (x=0), Mn4Si7 (x=0.250), Mn11Si19 (x=0.273), Mn15Si26 (x=0.267) and Mn27Si47 (x=0.259). These phases have very similar unit cells whose length varies from 1.75 nm for MnSi2 or Mn4Si7, which have almost the same structures, to 11.8 nm for Mn27Si47. MnSi2–x Nowotny phases have a Mn sublattice with a β-tin structure overlaid with a face-centered cubic Si sublattice. They resemble chimneys of transition metal atoms containing spiraling ladders of Si. These phases are semiconductors with a band gap of 0.4 to 0.9 eV. They exhibit a reasonably high thermoelectric figure of merit ZT ~ 0.8 and have potential applications in thermoelectric generator A thermoelectric generator (TEG), also c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Disilicide
Titanium disilicide ( Ti Si2) is an inorganic chemical compound of titanium and silicon. Preparation Titanium disilicide can be obtained from the reaction between titanium or titanium hydride with silicon. :Ti + 2 Si → TiSi2 It is also possible to prepare it aluminothermically by the ignition of aluminium powder, sulfur, silicon dioxide, and titanium dioxide or potassium hexafluorotitanate, K2TiF6, by electrolysis of a melt of potassium hexafluorotitanate and titanium dioxide, or by reaction of titanium with silicon tetrachloride. Another method is the reaction of titanium tetrachloride with silane, dichlorosilane or silicon. :TiCl4 + 2 SiH4 → TiSi2 + 4 HCl + 2 H2 :TiCl4 + 2 SiH2Cl2 + 2 H2 → TiSi2 + 8 HCl :TiCl4 + 3 Si → TiSi2 + SiCl4 Uses Titanium silicide is used in the semiconductor industry. It is typically grown by means of salicide The term salicide refers to a technology used in the microelectronics industry used to form electrical contacts between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermetallic Compound
An intermetallic (also called an intermetallic compound, intermetallic alloy, ordered intermetallic alloy, and a long-range-ordered alloy) is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elements. Intermetallics are generally hard and brittle, with good high-temperature mechanical properties. They can be classified as stoichiometric or nonstoichiometic intermetallic compounds. Although the term "intermetallic compounds", as it applies to solid phases, has been in use for many years, its introduction was regretted, for example by Hume-Rothery in 1955. Definitions Research definition Schulze in 1967 defined intermetallic compounds as ''solid phases containing two or more metallic elements, with optionally one or more non-metallic elements, whose crystal structure differs from that of the other constituents''. Under this definition, the following are included: #Electron (or Hume-Rothery) compounds #Size packing phases. e.g. Lav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicide
A silicide is a type of chemical compound that combines silicon and a (usually) more electropositive element. Silicon is more electropositive than carbon. Silicides are structurally closer to borides than to carbides. Similar to borides and carbides, the composition of silicides cannot be easily specified as covalent molecules. The chemical bonds in silicides range from conductive metal-like structures to covalent or ionic. Silicides of all non-transition metals, with exception of beryllium, have been described. Overview Silicon atoms in silicides can have many possible organizations: *Isolated silicon atoms: electrically conductive (or semiconductive) CrSi, MnSi, FeSi, CoSi, , , , , and nonconductive , *Si2 pairs: , hafnium and thorium silicides *Si4 tetrahedra: KSi, RbSi, CsSi *Si''n'' chains: USi, , CaSi, SrSi, YSi *Planar hexagonal graphite-like Si layers: β-USi2, silicides of other lanthanoids and actinoids *Corrugated hexagonal Si layers: CaSi2 *Open three-dimensio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Cobalt-based blue pigments ( cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was for a long time thought to be due to the known metal bismuth. Miners had long used the name ''kobold ore'' (German for ''goblin ore'') for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the ''kobold''. Today, some cobalt is produced specifically from one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Field
For a given temperature, the critical field refers to the maximum magnetic field strength below which a material remains superconducting. Superconductivity is characterized both by perfect conductivity (zero resistance) and by the complete expulsion of magnetic fields (the Meissner effect). Changes in either temperature or magnetic flux density can cause the phase transition between normal and superconducting states.High Temperature Superconductivity, Jeffrey W. Lynn Editor, Springer-Verlag (1990) The highest temperature under which the superconducting state is seen is known as the critical temperature. At that temperature even the weakest external magnetic field will destroy the superconducting state, so the strength of the critical field is zero. As temperature decreases, the critical field increases generally to a maximum at absolute zero. For a type-I superconductor the discontinuity in heat capacity seen at the superconducting transition is generally related to the slope of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Handbook Of Chemistry And Physics
The ''CRC Handbook of Chemistry and Physics'' is a comprehensive one-volume reference resource for science research. First published in 1914, it is currently () in its 103rd edition, published in 2022. It is sometimes nicknamed the "Rubber Bible" or the "Rubber Book", as CRC originally stood for "Chemical Rubber Company". As late as the 1962–1963 edition (3604 pages) the ''Handbook'' contained myriad information for every branch of science and engineering. Sections in that edition include: Mathematics, Properties and Physical Constants, Chemical Tables, Properties of Matter, Heat, Hygrometric and Barometric Tables, Sound, Quantities and Units, and Miscellaneous. Earlier editions included sections such as "Antidotes of Poisons", "Rules for Naming Organic Compounds", "Surface Tension of Fused Salts", "Percent Composition of Anti-Freeze Solutions", "Spark-gap Voltages", "Greek Alphabet", "Musical Scales", "Pigments and Dyes", "Comparison of Tons and Pounds", "Twist Drill and St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information technology. CRC Press is now a division of Taylor & Francis, itself a subsidiary of Informa. History The CRC Press was founded as the Chemical Rubber Company (CRC) in 1903 by brothers Arthur, Leo and Emanuel Friedman in Cleveland, Ohio, based on an earlier enterprise by Arthur, who had begun selling rubber laboratory aprons in 1900. The company gradually expanded to include sales of laboratory equipment to chemists. In 1913 the CRC offered a short (116-page) manual called the ''Rubber Handbook'' as an incentive for any purchase of a dozen aprons. Since then the ''Rubber Handbook'' has evolved into the CRC's flagship book, the '' CRC Handbook of Chemistry and Physics''. In 1964, Chemical Rubber decided to focus on its publishing ventures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
