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Rhenium(V) Chloride
Rhenium pentachloride is an inorganic compound of chlorine and rhenium. The compound has the formula Re2Cl10 but it is usually referred to as rhenium pentachloride. It is a red-brown solid. Structure and preparation Rhenium pentachloride has a bioctahedral structure and can be formulated as Cl4Re(μ-Cl)2ReCl4. The Re-Re distance is 3.74 Å. The motif is similar to that seen for tantalum pentachloride. This compound was first prepared in 1933, a few years after the discovery of rhenium. The preparation involves chlorination of rhenium at temperatures up to 900 °C. The material can be purified by sublimation. ReCl5 is one of the most oxidized binary chlorides of Re. It does not undergo further chlorination. ReCl6 has been prepared from rhenium hexafluoride. Rhenium heptafluoride is known but not the heptachloride. Uses and reactions It degrades in air to a brown liquid. Although rhenium pentachloride has no commercial applications, it is of historic significance a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal classes The table below org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhenium Hexafluoride
Rhenium hexafluoride, also rhenium(VI) fluoride, (ReF6) is a compound of rhenium and fluorine and one of the seventeen known binary hexafluorides. Synthesis Rhenium hexafluoride is made by combining rhenium heptafluoride with additional rhenium metal at 300 °C in a pressure vessel. :6 + Re → 7 Description Rhenium hexafluoride is a liquid at room temperature. At 18.5 °C, it freezes into a yellow solid. The boiling point is 33.7 °C. The solid structure measured at −140 °C is orthorhombic space group ''Pnma''. Lattice parameters are ''a'' = 9.417 Å, ''b'' = 8.570 Å, and ''c'' = 4.965 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 4.94 g·cm−3. The ReF6 molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group ('' Oh''). The Re–F bond length In molecular geometr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorides
The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water.Green, John, and Sadru Damji. "Chapter 3." ''Chemistry''. Camberwell, Vic.: IBID, 2001. Print. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating liquid flow in and out of cells. Less frequently, the word ''chloride'' may also form part of the "common" name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane (see IUPAC books) is an organic compound with a covalent C−Cl bond in which the chlorine is not an anion. Electronic properties A chloride ion (diameter 167 pm) is much larger than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhenium Compounds
Rhenium compounds are compounds formed by the transition metal rhenium (Re). Rhenium can form in many oxidation states, and compounds are known for every oxidation state from -3 to +7 except +2, although the oxidation states +7, +6, +4, and +2 are the most common. Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. These are white, water-soluble compounds. Tetrathioperrhenate anion eS4sup>− is possible. Chalcogenides Oxides Rhenium(IV) oxide (or rhenium dioxide) is an oxide of rhenium, with the formula ReO2. This gray to black crystalline solid is a laboratory reagent that can be used as a catalyst. It adopts the rutile structure. It forms via comproportionation: :2 Re2O7 + 3 Re → 7 ReO2 Single crystals are obtained by chemical transport, using iodine as the transporting agent. At high temperatures it undergoes disproportionation. It forms perrhenates with alkaline hydrogen peroxide and oxidizing acids. In m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhenium(IV) Chloride
Rhenium(IV) chloride is the inorganic compound with the formula ReCl4. This black solid is of interest as a binary phase but otherwise is of little practical value. A second polymorph of ReCl4 is also known. Preparation ReCl4 can be prepared by comproportionation of rhenium(V) chloride and rhenium(III) chloride. It can also be produced by reduction of rhenium(V) chloride with antimony trichloride. :\mathrm Tetrachloroethylene at 120 °C is also effective as a reductant: :\mathrm Structure X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ... reveals a polymeric structure. The Re–Re bonding distance is 2.728 Å. Re centers are octahedral, being surrounded by six chloride ligands. Pairs of octahedra share faces. The Re2Cl9 subunits are linked by bridging ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trirhenium Nonachloride
Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents. The compound is important in the history of inorganic chemistry as an early example of a cluster compound with metal-metal bonds. It is used as a starting material for synthesis of other rhenium complexes. Structure and physical properties As shown by X-ray crystallography trirhenium nonachloride consists of Re3Cl12 subunits that share three chloride bridges with adjacent clusters. The interconnected network of clusters forms sheets. Around each Re center are seven ligands, four bridging chlorides, one terminal chloride, and two Re-Re bonds.Colton, R. Chemistry of rhenium and technetium. 965. The heat of oxidation is evaluated according to the equation: :1/3 Re3Cl9 + 4 OH− + 2 OCl− → ReO4− + 2 H2O + 5Cl− The enthalpy for this process is 190.7 ± 0.2 kcal/mol. Preparation and reactions The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olefin Metathesis
Olefin metathesis is an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds. Because of the relative simplicity of olefin metathesis, it often creates fewer undesired by-products and hazardous wastes than alternative organic reactions. For their elucidation of the reaction mechanism and their discovery of a variety of highly active catalysts, Yves Chauvin, Robert H. Grubbs, and Richard R. Schrock were collectively awarded the 2005 Nobel Prize in Chemistry. Catalysts The reaction requires metal catalysts. Most commercially important processes employ heterogeneous catalysts. The heterogeneous catalysts are often prepared by in-situ activation of a metal halides (MClx) using organoaluminium or organotin compounds, e.g. combining MClx–EtAlCl2. A typical catalyst support is alumina. Commercial catalysts are often based on molybdenum and ruthenium. Well-defined organometallic co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhenium Heptafluoride
Rhenium heptafluoride is the compound with the formula ReF7. It is a yellow low melting solid and is the only thermally stable metal heptafluoride. It has a distorted pentagonal bipyramidal structure similar to IF7, which was confirmed by neutron diffraction at 1.5 K. The structure is non-rigid, as evidenced by electron diffraction studies. Production, reactions and properties Rhenium heptafluoride can be prepared from the elements at 400 °C: :2 Re + 7 F2 → 2 ReF7 It also can be produced by the explosion of rhenium metal under sulfur hexafluoride. It hydrolyzes under a base to form perrhenic acid and hydrogen fluoride: :ReF7 + 4H2O → HReO4 + 7HF With fluoride donors such as CsF, the ReF8− anion is formed, which has a square antiprismatic structure. With antimony pentafluoride Antimony pentafluoride is the inorganic compound with the formula Sb F5. This colourless, viscous liquid is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie International Edition
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the ''Journal Citation Reports'', the journal had a 2021 impact factor of 16.823. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'' ( (print), (online)), and a fully English-language edition, ''Angewandte Chemie International Edition'' ( (print), (online)). The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Business model ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhenium(VI) Chloride
Rhenium(VI) chloride is the inorganic compound with the formula ReCl6. It is a black paramagnetic solid. The molecules adopt an octahedral structure as seen in tungsten(VI) chloride. Preparation and reactions Rhenium(VI) chloride was first generated as a mixture by chlorination of Re films. Bulk samples can be prepared by combining rhenium hexafluoride with excess boron trichloride: :2 ReF6 + 6 BCl3 → ReCl6 + 6 BF2Cl It is unstable at room temperature with respect to rhenium(V) chloride Rhenium pentachloride is an inorganic compound of chlorine and rhenium. The compound has the formula Re2Cl10 but it is usually referred to as rhenium pentachloride. It is a red-brown solid. Structure and preparation Rhenium pentachloride has a ...: :2 ReCl6 → eCl5sub>2 + Cl2 References {{cite journal , doi=10.1038/194374a0, title=Rhenium Hexachloride, year=1962, last1=Colton, first1=R., journal=Nature, volume=194, issue=4826, pages=374–375, bibcode=1962Natur.194..374C, ... [...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. |
Chlorination Reaction
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens (F2, Cl2, Br2, I2). Halides are also commonly introduced using salts of the halides and halogen acids. Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride. Organic chemistry Several pathways exist for the halogenation of organic compounds, including free radical halogenation, ketone halogenation, electrophilic halogenation, and halogen addition reaction. The nature of the substrate determines the pathway. The facility of halogenation is influenced by the halogen. Fluorine and chlorine are more electrophilic and are m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
