|
Metal Carbonyl Cluster
In chemistry, a metal carbonyl cluster is a compound that contains two or more metals linked in part by metal-metal bonds and containing carbon monoxide (CO) as the exclusive or predominant ligand. The area is a subfield of metal carbonyl chemistry, and many metal carbonyl clusters are in fact prepared from simple metal carbonyls. Simple examples include Fe2(CO)9, Fe3(CO)12, Mn2(CO)10. High nuclearity clusters include h13(CO)24H3sup>2− and the stacked Pt3 triangules t3n(CO)6nsup>2− (n = 2–6). History The first metal carbonyl clusters, Fe3(CO)12, Ir4(CO)12, and Rh6(CO)16, were reported starting in the 1930s, often by Walter Hieber. The structures were subsequently established by X-ray crystallography.. Paolo Chini (1928–1980) was a pioneer for the synthesis and characterization of high nuclearity metal carbonyl clusters. His first studies started in 1958, in the attempt to repeat a patent that claimed an improved selectivity in hydroformylation. From a mixture of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a Chemical reaction, reaction with other Chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicobalt Octacarbonyl
Dicobalt octacarbonyl is an organocobalt compound with composition . This metal carbonyl is used as a reagent and catalyst in organometallic chemistry and organic synthesis, and is central to much known organocobalt chemistry. It is the parent member of a family of hydroformylation catalysts. Each molecule consists of two cobalt atoms bound to eight carbon monoxide ligands, although multiple structural isomers are known. Some of the carbonyl ligands are labile. Synthesis, structure, properties Dicobalt octacarbonyl an orange-colored, pyrophoric solid. It is synthesised by the high pressure carbonylation of cobalt(II) salts: : The preparation is often carried out in the presence of cyanide, converting the cobalt(II) salt into a hexacyanocobaltate(II) complex that reacts with carbon monoxide to yield . Acidification produces cobalt tetracarbonyl hydride, , which degrades near room temperature to dicobalt octacarbonyl and hydrogen. It can also be prepared by heating cobalt metal t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyhedral Skeletal Electron Pair Theory
In chemistry the polyhedral skeletal electron pair theory (PSEPT) provides electron counting rules useful for predicting the structures of clusters such as borane and carborane clusters. The electron counting rules were originally formulated by Kenneth Wade, and were further developed by others including Michael Mingos; they are sometimes known as Wade's rules or the Wade–Mingos rules. The rules are based on a molecular orbital treatment of the bonding. These notes contained original material that served as the basis of the sections on the 4''n'', 5''n'', and 6''n'' rules. These rules have been extended and unified in the form of the Jemmis ''mno'' rules. Predicting structures of cluster compounds Different rules (4''n'', 5''n'', or 6''n'') are invoked depending on the number of electrons per vertex. The 4''n'' rules are reasonably accurate in predicting the structures of clusters having about 4 electrons per vertex, as is the case for many boranes and carboranes. For such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jemmis Mno Rules
In chemistry, the Jemmis ''mno'' rules represent a unified rule for predicting and systematizing structures of compounds, usually clusters. The rules involve electron counting. They were formulated by Eluvathingal Devassy Jemmis to explain the structures of condensed polyhedral boranes such as , which are obtained by condensing polyhedral boranes by sharing a triangular face, an edge, a single vertex, or four vertices. These rules are additions and extensions to Wade's rules and polyhedral skeletal electron pair theory. The Jemmis ''mno'' rule provides the relationship between polyhedral boranes, condensed polyhedral boranes, and β-rhombohedral boron. This is similar to the relationship between benzene, condensed benzenoid aromatics, and graphite, shown by Hückel's 4''n'' + 2 rule, as well as the relationship between tetracoordinate tetrahedral carbon compounds and diamond. The Jemmis ''mno'' rules reduce to Hückel's rule when restricted to two dimensions and redu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Carbido Complex
A metal carbido complex is a coordination complex that contains a carbon atom as a ligand. Carbido complexes are a molecular subclass of carbides, which are prevalent. Carbido complexes represent models for intermediates in Fischer–Tropsch synthesis and related catalytic processes. They are also used as precursors for the synthesis of more complicated carbides. They are analogous to metal nitrido complexes. Carbido clusters Most molecular carbido complexes are clusters, usually featuring carbide as a six-fold bridging ligand. Examples include , and . The iron carbonyl carbides exist not only in the encapsulated carbon () but also with exposed carbon centres as in and . Clusters without CO ligands are also known. Doubly bridging carbide ligands Bridging carbido ligands can be subdivided into three classes: *cumulenic , *metallocarbyne , and *polar covalent . Cumulenic compounds generally bridge two metal atoms of the same element and are symmetrical. However, there are except ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonal Prism
In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The octahedron has eight faces, hence the prefix ''octa''. The octahedron is one of the Platonic solids, although octahedral molecules typically have an atom in their centre and no bonds between the ligand atoms. A perfect octahedron belongs to the point group Oh. Examples of octahedral compounds are sulfur hexafluoride SF6 and molybdenum hexacarbonyl Mo(CO)6. The term "octahedral" is used somewhat loosely by chemists, focusing on the geometry of the bonds to the central atom and not considering differences among the ligands themselves. For example, , which is not octahedral in the mathematical sense due to the orientation of the bonds, is referred to as octahedral. The concept of octahedral coordination geometry was developed by Alfred Werne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platinum Carbonyl Cluster Moteiff AKA Chini Cluster
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexachloroplatinate
Hexachloroplatinate is an anion with the chemical formula tCl6sup>2−. Chemical compounds containing the hexachloroplatinate anion include: *Chloroplatinic acid (or dihydrogen hexachloroplatinate), H2PtCl6 *Ammonium hexachloroplatinate, (NH4)2PtCl6 *Potassium hexachloroplatinate Potassium hexachloroplatinate is the inorganic compound with the formula K2PtCl6. It is a yellow solid that is an example of a comparatively insoluble potassium salt. The salt features the hexachloroplatinate(IV) dianion, which has octahedral coor ..., K2PtCl6 * Sodium hexachloroplatinate, Na2PtCl6 Related compounds/anions *The unstable hexachloropalladic acid (H2PdCl6) *Hexachloropalladate () * Hexafluoroplatinate () Anions Inorganic chlorine compounds Platinum(IV) compounds Chloro complexes Chlorometallates {{inorganic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrairidium Dodecacarbonyl
Tetrairidium dodecacarbonyl is the chemical compound with the formula Ir4(CO)12. This tetrahedral cluster is the most common and most stable "binary" carbonyl of iridium. This air-stable species is only poorly soluble in organic solvents. It has been used to prepare bimetallic clusters and catalysts, e.g. for the water gas shift reaction, and reforming, but these studies are of purely academic interest. Structure Each Ir center is octahedral, being bonded to 3 other iridium atoms and three terminal CO ligands. Ir4(CO)12 has Td symmetry with an average Ir-Ir distances of 2.693 Å. The related clusters Rh4(CO)12 and Co4(CO)12 have C3v symmetry because of the presence of three bridging CO ligands in each. Preparation It is prepared in two steps by reductive carbonylation of hydrated iridium trichloride Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is useful for preparing other iri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrarhodium Dodecacarbonyl
Tetrarhodium dodecacarbonyl is the chemical compound with the formula Rh4(CO)12. This dark-red crystalline solid is the smallest binary rhodium carbonyl that can be handled as a solid under ambient conditions. It is used as a catalyst in organic synthesis. Structure, synthesis, reactions According to X-ray crystallography, features a tetrahedral array of four Rh atoms with nine terminal CO ligands and three bridging CO ligands. The structure can be expressed as Rh4(CO)9(µ-CO)3. is prepared by treatment of an aqueous solution of rhodium trichloride with activated copper metal under an atmosphere of CO. :4 RhCl3(H2O)3 + 8 Cu + 22 CO → + 2 CO2 + 8 Cu(CO)Cl + 4 HCl + 10 H2O Alternatively, the compound can be prepared by treatment of a methanolic solution of RhCl3(H2O)3 with CO to afford H hCl2(CO)2 followed by carbonylation in the presence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8NoCo-Co.png "Click for more on -> Dicobalt Octacarbonyl")
15.png "Click for more on -> Metal Carbido Complex")
