|
Zirconium(III) Chloride
Zirconium(III) chloride is an inorganic compound with formula ZrCl3. It is a blue-black solid that is highly sensitive to air. Preparation The material was first claimed by Ruff and Wallstein who reduced zirconium tetrachloride with aluminium to give impure samples. Subsequently, the problem with aluminium contamination was solved when it was prepared by reduction using zirconium metal: :Zr + 3 ZrCl4 → 4 ZrCl3 When aluminium is used as the reducing agent with zirconium tetrachloride, a series of choloroaluminates are formed, for example r(AlCl4)2(AlCl4)2and Zr(AlCl4)3. Since the trihalides, such as zirconium trichloride, are comparatively nonvolatile, contamination can be avoided by using a gaseous reductant. For example, zirconium trichloride can be prepared by reduction of zirconium tetrachloride with hydrogen. :ZrCl4 + ½ H2 → ZrCl3 + HCl Structure Some zirconium halides (ZrCl3, ZrBr3, and ZrI3) have structures similar to HfI3. They also have similar space group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. History Discovery The word "''benzene''" derives from "''gum benzoin''" (benzoin res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Ruff
Otto Ruff (12 December 1871 – 17 September 1939) was a German chemist. Life Otto Ruff was born in Schwäbisch Hall, Württemberg. After becoming a pharmacist under the supervision of Carl Magnus von Hell (known from the Hell-Volhard-Zelinsky halogenation) at the University of Stuttgart he joined the group of Hermann Emil Fischer at the University of Berlin. Fischer was noted for his work on carbohydrates (sugars) and so Ruff started his career as an organic chemist. In 1898 he published his work on the transformation of d-Glucose to d-Arabinose, later called the Ruff degradation. Supported by the far-sighted Fischer, who recognized that while organic chemistry was now mature, physical chemistry was growing rapidly, Ruff became head of the new inorganic department in Berlin, working alongside Alfred Stock who was five years his junior. This drastic change in subject benefited Ruff during his work on chlorides sulfur compounds. In 1902 he married Meta Richter, a pharmacist, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium(III) Compounds
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', "gold-like" or "as gold"). It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, four of which are stable. Zirconium compounds have no known biological role. Characteristics Zirconium is a lustrous, greyish-white, soft, ductile, malleable metal that is solid at room temperature, though it is hard and brittle at lesser purities. In powder form, zirconium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohr Magneton
In atomic physics, the Bohr magneton (symbol ) is a physical constant and the natural unit for expressing the magnetic moment of an electron caused by its orbital or spin angular momentum. The Bohr magneton, in SI units is defined as \mu_\mathrm = \frac , And in Gaussian CGS units: \mu_\mathrm = \frac , where * is the elementary charge, * is the reduced Planck constant, * is the electron rest mass, * is the speed of light. History The idea of elementary magnets is due to Walther Ritz (1907) and Pierre Weiss. Already before the Rutherford model of atomic structure, several theorists commented that the magneton should involve the Planck constant ''h''. By postulating that the ratio of electron kinetic energy to orbital frequency should be equal to ''h'', Richard Gans computed a value that was twice as large as the Bohr magneton in September 1911. At the First Solvay Conference in November that year, Paul Langevin obtained a e\hbar/(12m_\mathrm). Langevin assumed that the attracti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Susceptibility
In electromagnetism, the magnetic susceptibility (Latin: , "receptive"; denoted ) is a measure of how much a material will become magnetized in an applied magnetic field. It is the ratio of magnetization (magnetic moment per unit volume) to the applied magnetizing field intensity . This allows a simple classification, into two categories, of most materials' responses to an applied magnetic field: an alignment with the magnetic field, , called paramagnetism, or an alignment against the field, , called diamagnetism. Magnetic susceptibility indicates whether a material is attracted into or repelled out of a magnetic field. Paramagnetic materials align with the applied field and are attracted to regions of greater magnetic field. Diamagnetic materials are anti-aligned and are pushed away, toward regions of lower magnetic fields. On top of the applied field, the magnetization of the material adds its own magnetic field, causing the field lines to concentrate in paramagnetism, or be excl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list was complete was only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hafnium(III) Iodide
Hafnium(III) iodide is an inorganic compound of hafnium and iodine with the formula Hf I3. It is a black solid. Preparation Like other group 4 trihalides, hafnium(III) iodide can be prepared from hafnium(IV) iodide by high-temperature reduction with hafnium metal, although incomplete reaction and contamination of the product with excess metal often occurs. :3 Hf I4 + Hf → 4 Hf I3 Other metals can be used as the reducing agent, for example aluminium. The product is often nonstoichiometric, with the compositions Hf I3.2–3.3 and Hf I3.0–3.5 reported. Structure and bonding Hafnium(III) iodide adopts the same crystal structure as zirconium(III) iodide Zirconium(III) iodide is an inorganic compound with the formula ZrI3. Preparation Like other group 4 trihalides, zirconium(III) iodide can be prepared from zirconium(IV) iodide by high-temperature reduction with zirconium metal, although incomple .... This is very similar to the Titanium(III) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium(III) Iodide
Zirconium(III) iodide is an inorganic compound with the formula ZrI3. Preparation Like other group 4 trihalides, zirconium(III) iodide can be prepared from zirconium(IV) iodide by high-temperature reduction with zirconium metal, although incomplete reaction and contamination of the product with excess metal often occurs. :3 ZrI4 + Zr → 4 ZrI3 An alternative is to crystallise zirconium(III) iodide from a solution of zirconium(III) in aluminium triiodide. The solution is prepared by reducing a eutectic solution of ZrI4 in liquid AlI3 at a temperature of 280–300 °C with metallic zirconium or aluminium. Structure and bonding Zirconium(III) iodide has a lower magnetic moment than is expected for the d1 metal ion Zr3+, indicating non-negligible Zr–Zr bonding. The crystal structure of zirconium(III) iodide is based on hexagonal close packing of iodide ions with one third of the octahedral interstices An interstitial space or interstice is a space between structures or objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium(III) Bromide
Zirconium(III) bromide is an inorganic compound with the formula ZrBr3. Preparation Almost all the trihalides of titanium, zirconium and hafnium can be prepared by the high-temperature reduction of the corresponding tetrahalide with the metal. Incomplete reaction and contamination of the product with excess metal often occurs. Zirconium(III) bromide can thus be prepared from zirconium(IV) bromide and zirconium foil. :3 ZrBr4 + Zr → 4 ZrBr3 Alternatively, zirconium(III) bromide crystallises from a solution of zirconium(III) in aluminium tribromide. The solution is prepared by reducing a eutectic solution of ZrBr4 in liquid AlBr3 at a temperature of 230–300 °C with metallic zirconium or aluminium. Structure and bonding Zirconium(III) bromide has a lower magnetic moment than is expected for the d1 metal ion Zr3+, indicating non-negligible Zr-Zr bonding. The crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, io ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium Tetrachloride
Zirconium(IV) chloride, also known as zirconium tetrachloride, () is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air. Structure Unlike molecular TiCl4, solid ZrCl4 adopts a polymeric structure wherein each Zr is octahedrally coordinated. This difference in structures is responsible for the disparity in their properties: is distillable, but is a solid. In the solid state, ZrCl4 adopts a tape-like linear polymeric structure—the same structure adopted by HfCl4. This polymer degrades readily upon treatment with Lewis bases, which cleave the Zr-Cl-Zr linkages. Synthesis This conversion entails treatment of the oxide with carbon as the oxide "getter" in the presence of chlorine at high temperature: :ZrO2 + 2 C + 2 Cl2 → ZrCl4 + 2 CO A laboratory scale process uses carbon tetrachloride in place of carbon and chlorine: :ZrO2 + 2 CCl4 → ZrCl4 + 2 COCl2 Applications Precursor to Zr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Sensitive
Air sensitivity is a term used, particularly in chemistry, to denote the reactivity of chemical compounds with some constituent of air. Most often, reactions occur with atmospheric oxygen (O2) or water vapor (H2O), although reactions with the other constituents of air such as carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2) are also possible. Method A variety of air-free techniques have been developed to handle air-sensitive compounds. Two main types of equipment are gloveboxes and Schlenk lines. Glove boxes are sealed cabinets filled with an inert gas such as argon or nitrogen. Normal laboratory equipment can be set up in the glovebox, and manipulated by the use of gloves that penetrate its walls. The atmosphere can be regulated to approximately atmospheric pressure and set to be pure nitrogen or other gas with which the chemicals will not react. Chemicals and equipment can be transferred in and out via an airlock. A Schlenk line is a vacuum and inert-gas dual-mani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2.png "Click for more on -> Benzene")
