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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] |
Orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular Prism (geometry), prism with a rectangular Base (geometry), base (''a'' by ''b'') and height (''c''), such that ''a'', ''b'', and ''c'' are distinct. All three bases intersect at 90° angles, so the three lattice vectors remain mutually orthogonal. Bravais lattices There are four orthorhombic Bravais lattices: primitive orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic. For the base-centered orthorhombic lattice, the primitive cell has the shape of a right rhombic prism;See , row oC, column Primitive, where the cell parameters are given as a1 = a2, α = β = 90° it can be constructed because the two-dimensional centered rectangular base layer can also be descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Powder
Aluminium powder is powdered aluminium. This was originally produced by mechanical means using a stamp mill to create flakes. Subsequently, a process of spraying molten aluminium to create a powder of droplets was developed by E. J. Hall in the 1920s. The resulting powder might then be processed further in a ball mill to flatten it into flakes for use as a coating or pigment. Aluminium powder features low density with high conductivity. Characteristics Powdered aluminium shares many of the physical characteristics of bulk aluminium such as its molecular weight of 26.981538 g mol−1, melting point of 660 °C, and a boiling point of 2460 °C. It combusts at a much faster rate to bulk aluminium, this is due to the fact that the gaps between the particles allow for more air and therefor faster oxidization. Usage * autoclave aerated concrete * cosmetic colourant * fingerprint powder * metallic paint * pyrotechnics (including the M-80 firecracker) * refractory * r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salicide
The term salicide refers to a technology used in the microelectronics industry used to form electrical contacts between the semiconductor device and the supporting interconnect structure. The salicide process involves the reaction of a metal thin film with silicon in the active regions of the device, ultimately forming a metal silicide contact through a series of annealing and/or etch processes. The term "salicide" is a compaction of the phrase self-aligned silicide. The description "self-aligned" suggests that the contact formation does not require photolithography patterning processes, as opposed to a non-aligned technology such as polycide. The term salicide is also used to refer to the metal silicide formed by the contact formation process, such as "titanium salicide", although this usage is inconsistent with accepted naming conventions in chemistry. Contact formation The salicide process begins with deposition of a thin transition metal layer over fully formed and pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichlorosilane
Dichlorosilane, or DCS as it is commonly known, is a chemical compound with the formula H2SiCl2. In its major use, it is mixed with ammonia (NH3) in LPCVD chambers to grow silicon nitride in semiconductor processing. A higher concentration of DCS·NH3 (i.e. 16:1), usually results in lower stress nitride films. History Dichlorosilane was originally prepared by Stock and Somieski by the reaction of SiH4 with hydrogen chloride. Dichlorosilane reacts with water vapor to initially give monomeric prosiloxane: Monomeric polymerizes rapidly upon condensation or in solution.Seyferth, D., Prud'Homme, C., Wiseman, G., Cyclic Polysiloxanes from the Hydrolysis of Dichlorosilane, Inorganic Chemistry, 22, 2163-2167 Reactions and formation Most dichlorosilane results as a byproduct of the reaction of HCl with silicon, a reaction intended to give trichlorosilane. Disproportionation In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silane
Silane (Silicane) is an inorganic compound with chemical formula . It is a colorless, pyrophoric gas with a sharp, repulsive, pungent smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Silanes with alkyl groups are effective water repellents for mineral surfaces such as concrete and masonry. Silanes with both organic and inorganic attachments are used as coupling agents. They are commonly used to apply coatings to surfaces or as an adhesion promoter. Production Commercial-scale routes Silane can be produced by several routes. Typically, it arises from the reaction of hydrogen chloride with magnesium silicide: : It is also prepared from metallurgical-grade silicon in a two-step process. First, silicon is treated with hydrogen chloride at about 300 °C to produce trichlorosilane, HSiCl3, along with hydrogen gas, according to the chemical equation : The trichlorosilane is then converted to a mixture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Tetrachloride
Titanium tetrachloride is the inorganic compound with the formula . It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide () and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4", as a phonetic representation of the symbols of its molecular formula (). Properties and structure is a dense, colourless liquid, although crude samples may be yellow or even red-brown. It is one of the rare transition metal halides that is a liquid at room temperature, being another example. This property reflects the fact that molecules of weakly self-associate. Most metal chlorides are polymers, wherein the chloride atoms bridge between the metals. Its melting point is similar to that of . has a "closed" electronic shell, with the same number of electrons as the nobl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Tetrachloride
Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colorless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. It is a part of the chlorosilane family. Preparation Silicon tetrachloride is prepared by the chlorination of various silicon compounds such as ferrosilicon, silicon carbide, or mixtures of silicon dioxide and carbon. The ferrosilicon route is most common. In the laboratory, can be prepared by treating silicon with chlorine at : : It was first prepared by Jöns Jakob Berzelius in 1823. Brine can be contaminated with silica when the production of chlorine is a byproduct of a metal refining process from metal chloride ore. In rare occurrences, the silicon dioxide in silica is converted to silicon tetrachloride when the contaminated brine is electrolyzed. Reactions Hydrolysis and related reactions Like other chlorosilanes or silanes, silicon tetrachl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Hexafluorotitanate
Potassium hexafluorotitanate is an inorganic compound of potassium, fluorine, and titanium with the chemical formula . Synthesis Hydrofluoric acid reacts with metatitanic acid to generate fluorotitanic acid; then it is neutralized with potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ... to produce potassium hexafluorotitanate. Physical properties The compound forms white powder. Potassium hexafluorotitanate is soluble in hot water, slightly soluble in cold water, and inorganic acid. Insoluble in ammonia. Chemical properties Reacts with sodium to form titanium, potassium monofluoride and sodium monofluoride: : Uses The compound is used as an analytical reagent, also used in the manufacture of titanic acid and metallic titanium. Can also be used as a catalyst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Dioxide
Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound derived from titanium with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or Colour Index International, CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion. Structure In all three of its main dioxides, titanium exhibits Octahedral molecular geometry, octahedral geometry, being bonded to six oxide anions. The oxides in turn are bonded to three Ti centers. The overall crystal structures of rutile and anatase are tetragonal in symmetry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Dioxide
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product. Examples include fused quartz, fumed silica, opal, and aerogels. It is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries. All forms are white or colorless, although impure samples can be colored. Silicon dioxide is a common fundamental constituent of glass. Structure In the majority of silicon dioxides, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminothermic Reaction
Aluminothermic reactions are exothermic reaction, exothermic chemical reactions using aluminium as the reducing agent at high temperature. The process is industrially useful for production of alloys of iron. The most prominent example is the thermite reaction between iron oxides and aluminium to produce iron itself: : Fe2O3 + 2 Al → 2 Fe + Al2O3 This specific reaction is however not relevant to the most important application of aluminothermic reactions, the production of ferroalloys. For the production of iron, a cheaper reducing agent, Coke (fuel), coke, is used instead via the carbothermic reaction. History Aluminothermy started from the experiments of Russian scientist Nikolay Beketov at the University of Kharkiv in Ukraine, who proved that aluminium restored metals from their oxides under high temperatures. The reaction was first used for the carbon-free reduction of metal oxides. The reaction is highly exothermic, but it has a high activation energy since strong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
