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Ruthenium(III) Chloride
Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·''x''H2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry. Preparation and properties Anhydrous ruthenium(III) chloride is usually prepared by heating powdered ruthenium metal with chlorine. In the original synthesis, the chlorination was conducted in the presence of carbon monoxide, the product being carried by the gas stream and crystallising upon cooling. Two allotropes of RuCl3 are known. The black α-form adopts the CrCl3-type structure with long Ru-Ru contacts of 346 pm. This allotrope has honeycomb layers of Ru3+ which are surrounded with an octahedral cage of Cl− anions. The ruthenium cations are magnetic residing in a low-spin J~1/2 ground st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonal
In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crystal system and the rhombohedral lattice system are not equivalent (see section crystal systems below). In particular, there are crystals that have trigonal symmetry but belong to the hexagonal lattice (such as α-quartz). The hexagonal crystal family consists of the 12 point groups such that at least one of their space groups has the hexagonal lattice as underlying lattice, and is the union of the hexagonal crystal system and the trigonal crystal system. There are 52 space groups associated with it, which are exactly those whose Bravais lattice is either hexagonal or rhombohedral. __TOC__ Lattice systems The hexagonal crystal family consists of two lattice systems: hexagonal and rhombohedral. Each lattice system consists of one Bravais l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enthalpy
Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant pressure, which is conveniently provided by the large ambient atmosphere. The pressure–volume term expresses the work required to establish the system's physical dimensions, i.e. to make room for it by displacing its surroundings. The pressure-volume term is very small for solids and liquids at common conditions, and fairly small for gases. Therefore, enthalpy is a stand-in for energy in chemical systems; bond, lattice, solvation and other "energies" in chemistry are actually enthalpy differences. As a state function, enthalpy depends only on the final configuration of internal energy, pressure, and volume, not on the path taken to achieve it. In the International System of Units (SI), the unit of measurement for enthalpy is the joule. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis-Dichlorobis(bipyridine)ruthenium(II)
''cis''-Dichlorobis(bipyridine)ruthenium(II) is the coordination complex with the formula RuCl2(bipy)2, where bipy is 2,2'-bipyridine. It is a dark green diamagnetic solid that is a precursor to many other complexes of ruthenium, mainly by substitution of the two chloride ligands. The compound has been crystallized as diverse hydrates. Synthesis and structure The complex is prepared by heating a DMF solution of ruthenium trichloride and bipyridine. With octahedral coordination geometry, the complex exists exclusively as the chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from ... cis isomer. The corresponding Ru(III) salts are also known.{{cite journal, title=Structural Variations Induced by Changes in Oxidation State and Their Role in Electron Transfer. Crystal and Molecular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,2'-bipyridine
The comma is a punctuation mark that appears in several variants in different languages. It has the same shape as an apostrophe or single closing quotation mark () in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight, but inclined from the vertical. Other fonts give it the appearance of a miniature filled-in figure on the baseline. The comma is used in many contexts and languages, mainly to separate parts of a sentence such as clauses, and items in lists mainly when there are three or more items listed. The word ''comma'' comes from the Greek (), which originally meant a cut-off piece, specifically in grammar, a short clause. A comma-shaped mark is used as a diacritic in several writing systems and is considered distinct from the cedilla. In Byzantine and modern copies of Ancient Greek, the " rough" and "smooth breathings" () appear above the letter. In Latvian, R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruthenium Tris(bipyridine) Chloride
Tris(bipyridine)ruthenium(II) chloride is the chloride salt coordination complex with the formula u(bpy)3sup>2+ 2Cl−. This polypyridine complex is a red crystalline salt obtained as the hexahydrate, although all of the properties of interest are in the cation u(bpy)3sup>2+, which has received much attention because of its distinctive optical properties. The chlorides can be replaced with other anions, such as PF6−. Synthesis and structure left, 144px, Cis-Dichlorobis(bipyridine)ruthenium(II), ''cis''-Dichlorobis(bipyridine)ruthenium(II) is an intermediate in the synthesis of tris(bipyridine)ruthenium(II) chloride. This salt is prepared by treating an aqueous solution of ruthenium trichloride with 2,2'-bipyridine. In this conversion, Ru(III) is reduced to Ru(II), and hypophosphorous acid is typically added as a reducing agent. u(bpy)3sup>2+ is octahedral, containing a central low spin d6 Ru(II) ion and three bidentate bpy ligands. The Ru-N distances are 2.053(2), shorter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,4-Cyclohexadiene
1,4-Cyclohexadiene is an organic compound with the formula C6H8. It is a colourless, flammable liquid that is of academic interest as a prototype of a large class of related compounds called terpenoids, an example being γ-terpinene. An isomer of this compound is 1,3-cyclohexadiene. Synthesis and reactions In the laboratory, substituted 1,4-cyclohexadienes are synthesized by Birch reduction of related aromatic compounds using an alkali metal dissolved in liquid ammonia and a proton donor such as an alcohol. In this way, over reduction to the fully saturated ring is avoided. 1,4-Cyclohexadiene and its derivatives are easily aromatized, the driving force being the formation of an aromatic ring. The conversion to an aromatic system may be used to trigger other reactions, such as the Bergman cyclization The Masamune-Bergman cyclization or Masamune-Bergman reaction or Masamune-Bergman cycloaromatization is an organic reaction and more specifically a rearrangement reaction taking p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-Cyclohexadiene
Cyclohexa-1,3-diene is an organic compound with the formula (C2H4)(CH)4. It is a colorless, flammable liquid. Its refractive index is 1.475 (20 °C, D). A naturally occurring derivative of 1,3-cyclohexadiene is terpinene, a component of pine oil. Synthesis Cyclohexadiene is prepared by the dehydrobromination of 1,2-dibromocyclohexane: :(CH2)4(CHBr)2 + 2 NaH → (CH2)2(CH)4 + 2 NaBr + 2 H2 Reactions Useful reactions of this diene are cycloadditions, such as the Diels-Alder reaction. Conversion of cyclohexa-1,3-diene to benzene + hydrogen is exothermic by about 25 kJ/mol in the gas phase. :cyclohexane → cyclohexa-1,3-diene + 2 H2 (Δ''H'' = +231.5 kJ/mol; endothermic) :cyclohexane → benzene + 3 H2 (Δ''H'' = +205 kJ/mol; endothermic) :cyclohexa-1,3-diene → benzene + H2 (Δ''H'' = -26.5 kJ/mol; exothermic) Compared with its isomer cyclohexa-1,4-diene, cyclohexa-1,3-diene is about 1.6 kJ/mol more stable. Cyclohexadiene and its derivatives form metal-alkene complexes. Ill ... [...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] |
Diruthenium Tetraacetate Chloride
Diruthenium tetraacetate chloride is the coordination polymer with the formula n. A red brown solid, the compound is obtained by the reduction of ruthenium trichloride in acetic acid. The compound has attracted much academic interest because it features a fractional metal-metal bond order of 2.5. The u2(O2CCH3)4sup>+ core adopts the Chinese lantern structure, with four acetate ligands spanning the Ru2 center. The Ru-Ru distance is 228 pm. The u2(O2CCH3)4sup>+ cages are linked by bridging chloride ligand In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually r ...s. References {{Acetates Ruthenium compounds Acetates Dimers (chemistry) Chemical compounds containing metal–metal bonds Mixed valence compounds Chloro complexes Coordination polymers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichlorotris(triphenylphosphine)ruthenium(II)
Dichlorotris(triphenylphosphine)ruthenium(II) is a coordination complex of ruthenium. It is a chocolate brown solid that is soluble in organic solvents such as benzene. The compound is used as a precursor to other complexes including those used in homogeneous catalysis. Synthesis and basic properties RuCl2(PPh3)3 is the product of the reaction of ruthenium trichloride trihydrate with a methanolic solution of triphenylphosphine. :2 RuCl3(H2O)3 + 7 PPh3 → 2 RuCl2(PPh3)3 + 2 HCl + 5 H2O + OPPh3 The coordination sphere of RuCl2(PPh3)3 can be viewed as either five-coordinate or octahedral. One coordination site is occupied by one of the hydrogen atoms of a phenyl group. This Ru---H agostic interaction is long (2.59 Å) and weak. The low symmetry of the compound is reflected by the differing lengths of the Ru-P bonds: 2.374, 2.412, and 2.230 Å. The Ru-Cl bond lengths are both 2.387 Å. Reactions In the presence of excess of triphenylphosphine, RuCl2(PPh3)3 binds a four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Majorana Fermion
A Majorana fermion (, uploaded 19 April 2013, retrieved 5 October 2014; and also based on the pronunciation of physicist's name.), also referred to as a Majorana particle, is a fermion that is its own antiparticle. They were hypothesised by Ettore Majorana in 1937. The term is sometimes used in opposition to a Dirac fermion, which describes fermions that are not their own antiparticles. With the exception of neutrinos, all of the Standard Model fermions are known to behave as Dirac fermions at low energy (lower than the electroweak symmetry breaking temperature), and none are Majorana fermions. The nature of the neutrinos is not settled – they may turn out to be either Dirac or Majorana fermions. In condensed matter physics, quasiparticle excitations can appear like bound Majorana fermions. However, instead of a single fundamental particle, they are the collective movement of several individual particles (themselves composite) which are governed by non-Abelian statistics. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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