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Tungsten Oxytetrafluoride
Tungsten oxytetrafluoride is an inorganic compound with the formula . It is a colorless diamagnetic solid. The compound is one of many oxides of tungsten. It is usually encountered as product of the partial hydrolysis of tungsten hexafluoride. Structure As confirmed by X-ray crystallography, crystallizes as a tetramer. The oxides are terminal, and four of the fluorides are bridging ligand, bridging. Its structure is similar to those for niobium pentafluoride and tantalum pentafluoride. In contrast, molybdenum oxytetrafluoride adopts a polymeric structure, although again the fluorides bridge and the oxides are terminal. In the gas state, this molecule is a monomer. It can form complexes with acetonitrile and other compounds. Preparation Tungsten(VI) oxytetrafluoride can be synthesized by the reaction of fluorine and tungsten trioxide. It can also be obtained by treating tungsten with a mixture of oxygen and fluorine at high temperatures. Partial hydrolysis of tungsten hexaflu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane (often abbreviated as TCM), is an organochloride with the formula and a common solvent. It is a volatile, colorless, sweet-smelling, dense liquid produced on a large scale as a precursor to refrigerants and polytetrafluoroethylene (PTFE). Chloroform was once used as an inhalational anesthetic between the 19th century and the first half of the 20th century. It is miscible with many solvents but it is only very slightly soluble in water (only 8 g/L at 20°C). Structure and name The molecule adopts a tetrahedral molecular geometry with C3v symmetry. The chloroform molecule can be viewed as a methane molecule with three hydrogen atoms replaced with three chlorine atoms, leaving a single hydrogen atom. The name "chloroform" is a portmanteau of ''terchloride'' (tertiary chloride, a trichloride) and ''formyle'', an obsolete name for the methylylidene radical (CH) derived from formic acid. Natural occurrence Many kinds of seaweed produce chlor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tantalum Pentafluoride
Tantalum(V) fluoride is the inorganic compound with the formula . It is one of the principal molecular compounds of tantalum. Characteristic of some other pentafluorides, the compound is volatile but exists as a tetramer in the solid state. Preparation and structure is prepared by treating tantalum metal with fluorine gas. : is prepared similarly. Solid and molten is tetrameric, consisting of four octahedral centers linked via bridging fluoride centers. Gaseous is monomeric and adopts the trigonal bipyramidal structure with D3h symmetry. Reactions and derivatives The tendency of to form clusters in the solid state indicates the Lewis acidity of the monomer. Indeed, reacts with fluoride sources to give the ions (hexafluorotantalate(V)), (heptafluorotantalate(V)), and (octafluorotantalate(V)). With neutral Lewis bases, such as diethyl ether, forms adducts. is used in combination with HF as a catalyst for the alkylation of alkanes and alkenes and for the protonati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Halides
Metal halides are compounds between metals and halogens. Some, such as sodium chloride are Ionic compound, ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride. File:NaCl polyhedra.svg, Sodium chloride crystal structure File:Uranium-hexafluoride-unit-cell-3D-balls.png, Discrete UF6 molecules File:Alpha-palladium(II)-chloride-xtal-3D-balls.png, Infinite chains of one form of palladium chloride Preparation The halogens can all react with metals to form metal halides according to the following equation: :2M + nX2 → 2MXn where M is the metal, X is the halogen, and MXn is the metal halide. In practice, this type of reaction may be very exothermic, hence impractical as a preparative technique. Additionally, many transition metals can adopt multiple oxidation states, which complicates matters. As the halogens are strong oxidizers, direct combination of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungstic Acid
Tungstic acid refers to hydrated forms of tungsten trioxide, WO3. Both a monohydrate (WO3·H2O) and hemihydrate (WO3·1/2 H2O) are known. Molecular species akin to sulfuric acid, i.e. (HO)2WO2 are not observed. The solid-state structure of WO3·H2O consists of layers of octahedrally coordinated WO5(H2O) units where 4 vertices are shared. The dihydrate has the same layer structure with the extra H2O molecule intercalated. The monohydrate is a yellow solid and insoluble in water. The classical name for this acid is 'acid of wolfram'. Salts of tungstic acid are tungstates. The acid was discovered by Carl Wilhelm Scheele Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a Swedish Pomerania, German-Swedish pharmaceutical chemist. Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified the elements molybd ... in 1781.Scheele, Carl Wilhelm (1781"Tungstens bestånds-delar"(Tungsten's Scheelite.html" ;"title=".e., Sch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Oxide
Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. It occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. Types Lead oxide exists in two polymorphs: * Red tetragonal (α-PbO), obtained at temperatures below * Yellow orthorhombic (β-PbO), obtained at temperatures above Synthesis PbO may be prepared by heating lead metal in air at approximately . At this temperature it is also the end product of decomposition of other oxides of lead in air: :PbO2->[] Pb12O19 ->[] Pb12O17 ->[] Pb3O4 ->[] PbO Thermal decomposition of lead(II) nitrate or lead carbonate, lead(II) carbonate also results in the formation of PbO: :2 → 2 PbO + 4 + : → PbO + PbO is produced on a large scale as an intermediate product in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Fluoride
Lead(II) fluoride is the inorganic compound with the formula Pb F2. It is a white solid. The compound is polymorphic, at ambient temperatures it exists in orthorhombic (PbCl2 type) form, while at high temperatures it is cubic ( Fluorite type). Preparation Lead(II) fluoride can be prepared by treating lead(II) hydroxide or lead(II) carbonate with hydrofluoric acid: : Pb(OH)2 + 2 HF → PbF2 + 2 H2O Alternatively, it is precipitated by adding hydrofluoric acid to a lead(II) salt solution, or by adding a fluoride salt to a lead salt, such as potassium fluoride to a lead(II) nitrate solution, : 2 KF + Pb(NO3)2 → PbF2 + 2 KNO3 or sodium fluoride to a lead(II) acetate solution. : 2 NaF + Pb(CH3COO)2 → PbF2 + 2 NaCH3COO It appears as the very rare mineral fluorocronite. Uses Lead(II) fluoride is used in low melting glasses, in glass coatings to reflect infrared rays, in phosphors for television-tube screens, and as a catalyst for the manufacture of picoline. The Muon g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Chloride
The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl. Reactions Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a Polar-covalent bond, polar covalent bond. The chlorine atom is much more Electronegativity, electronegative than the hydrogen atom, which makes this bond polar. Consequently, the molecule has a large Molecular dipole moment, dipole moment with a negative partial charge (δ−) at the chlorine atom and a positive partial charge (δ+) at the hydrogen atom. In part because of its high polarity, HCl is very soluble in water (and in other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten(VI) Oxytetrachloride
Tungsten(VI) oxytetrachloride is the inorganic compound with the formula . This diamagnetic solid is used to prepare other complexes of tungsten. The red crystalline compound is soluble in nonpolar solvents but it reacts with alcohols and water and forms adducts with Lewis bases. Structure The solid consists of weakly associated square pyramidal monomers. The compound is classified as an oxyhalide. Synthesis and reactions is prepared from tungsten trioxide or hexachloride: : : It is "difficult to prepare by other means," but thionyl chloride also oxidizes tungsten(IV) oxide to the oxytetrachloride at 200 °C. is a Lewis acid. It is a precursor to catalysts used for polymerization of alkyne \ce \ce Acetylene \ce \ce \ce Propyne \ce \ce \ce \ce 1-Butyne In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and n ...s. References {{Tungsten com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Fluoride
Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils near room temperature, a much higher temperature than other hydrogen halides. Hydrogen fluoride is an extremely dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. The gas can also cause blindness by rapid destruction of the corneas. History In 1771 Carl Wilhelm Scheele prepared the aqueous solution, hydrofluoric acid in large quantities, although hydrofluoric acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten Trioxide
Tungsten(VI) oxide, also known as tungsten trioxide is a chemical compound of oxygen and the transition metal tungsten, with formula WO3. The compound is also called tungstic anhydride, reflecting its relation to tungstic acid . It is a light yellow crystalline solid. Tungsten(VI) oxide occurs naturally in the form of hydrates, which include minerals: tungstite WO3·H2O, meymacite WO3·2H2O and hydrotungstite (of the same composition as meymacite, however sometimes written as H2WO4). These minerals are rare to very rare secondary tungsten minerals. History In 1841, a chemist named Robert Oxland gave the first procedures for preparing tungsten trioxide and sodium tungstate. He was granted patents for his work soon after, and is considered to be the founder of systematic tungsten chemistry. Structure and properties The crystal structure of tungsten trioxide is temperature dependent. It is tetragonal at temperatures above 740 °C, orthorhombic from 330 to 740 °C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extremely Reactivity (chemistry), reactive as it reacts with all other Periodic table, elements except for the light Noble gas, noble gases. It is highly toxicity, toxic. Among the elements, fluorine ranks Abundance of the chemical elements, 24th in cosmic abundance and 13th in crustal abundance. Fluorite, the primary mineral source of fluorine, which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb meaning gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its compounds, and several early experimenters died or sustained injuries from their attempts. Only in 1886 did French chemist He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
