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Iron Tetracarbonyl Hydride
Iron tetracarbonyl dihydride is the organometallic compound with the formula H2Fe(CO)4. This compound was the first transition metal hydride discovered. The complex is stable at low temperatures but decomposes rapidly at temperatures above –20 °C. Preparation Iron tetracarbonyl dihydride was first produced by Hieber and Leutert from iron pentacarbonyl, which is first converted to HFe(CO): :Fe(CO)5 + 2 OH− → HFe(CO) + HCO :HFe(CO) + H+ → H2Fe(CO)4 Since the compound is thermally labile and sensitive to light, ideal conditions in 1930's Munich called for winter nights. The early method was called the "polar night synthesis." As recommended by Hieber and Leutert, the compound can be purified by trap-to-trap distillation. Structure and properties In iron tetracarbonyl hydride the Fe(CO)4 group has C''2v'' molecular symmetry with a geometry intermediate between octahedral and tetrahedral. Viewed as an octahedral complex, the hydride ligands are ''cis''. Viewed a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organometallic Compound
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganics, metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal Hydride
Transition metal hydrides are chemical compounds containing a transition metal bonded to hydrogen. Most transition metals form hydride complexes and some are significant in various catalytic and synthetic reactions. The term "hydride" is used loosely: some of them are acidic (e.g., H2Fe(CO)4), whereas some others are hydridic, having H−-like character (e.g., ZnH2). Classes of metal hydrides Binary metal hydrides Many transition metals form compounds with hydrogen, called binary hydrides: binary, because these compounds contain only two elements, and hydride, because the hydrogenic ligand is assumed to have hydridic (H−-like) character. These compounds are invariably insoluble in all solvents, reflecting their polymeric structures. They often exhibit metal-like electrical conductivity. Many are nonstoichiometric compounds. Electropositive metals ( Ti, Zr, Hf, Zn) and some other metals form hydrides with the stoichiometry MH or sometimes MH2 (M = Ti, Zr, Hf, V, Zn). The b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Pentacarbonyl
Iron pentacarbonyl, also known as iron carbonyl, is the compound with formula . Under standard conditions Fe( CO)5 is a free-flowing, straw-colored liquid with a pungent odour. Older samples appear darker. This compound is a common precursor to diverse iron compounds, including many that are useful in small scale organic synthesis. Properties Iron pentacarbonyl is a homoleptic metal carbonyl, where carbon monoxide is the only ligand complexed with a metal. Other examples include octahedral Cr(CO)6 and tetrahedral Ni(CO)4. Most metal carbonyls have 18 valence electrons, and Fe(CO)5 fits this pattern with 8 valence electrons on Fe and five pairs of electrons provided by the CO ligands. Reflecting its symmetrical structure and charge neutrality, Fe(CO)5 is volatile; it is one of the most frequently encountered liquid metal complexes. Fe(CO)5 adopts a trigonal bipyramidal structure with the Fe atom surrounded by five CO ligands: three in equatorial positions and two axially b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Tetracarbonyliron Hydride
Potassium tetracarbonyliron hydride is the inorganic salt with the formula K Fe(CO)4 A pale yellow solid, it is the potassium salt of Fe(CO)4sup>−, which is the conjugate base of iron tetracarbonyl dihydride: :H2Fe(CO)4 + KOH → K Fe(CO)4 + H2O Potassium tetracarbonyliron hydride is prepared by treating iron pentacarbonyl with potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...: :Fe(CO)5 + 2 KOH → K Fe(CO)4 + KHCO3 Potassium tetracarbonyliron hydride is an intermediate in the synthesis of trisubstituted phosphine complexes:{{cite book , doi=10.1002/9780470132623.ch30, chapter=One-Pot Synthesis of Dicarbonyltris(Phosphane)Iron(0) Complexes from Pentacarbonyliron, series=Inorganic Syntheses, year=1996, last1=Brunet, first1=J.-J., last2=Kindela, fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naturwissenschaften
''The Science of Nature'', formerly ''Naturwissenschaften'', is a monthly peer-reviewed scientific journal published by Springer Science+Business Media covering all aspects of the natural sciences relating to questions of biological significance. It was founded in 1913 and intended as a German-language equivalent of the English-language journal ''Nature'', at a time when German was still a dominant language of the natural sciences. The journal is now published in English. History ''Die Naturwissenschaften'' was founded in 1913 by Arnold Berliner and published by Julius Springer Verlag. Berliner intended to create a German equivalent to the English-language journal ''Nature''. The original subtitle ''Wochenschrift für die Fortschritte der Naturwissenschaften, der Medizin und der Technik'' (''Weekly Publication of the Advances in the Natural Sciences, Medicine and Technology'') was later changed to its current ''The Science of Nature''. The journal is published monthly and the art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Symmetry
Molecular symmetry in chemistry describes the symmetry present in molecules and the classification of these molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can be used to predict or explain many of a molecule's chemical properties, such as whether or not it has a dipole moment, as well as its allowed spectroscopic transitions. To do this it is necessary to use group theory. This involves classifying the states of the molecule using the irreducible representations from the character table of the symmetry group of the molecule. Symmetry is useful in the study of molecular orbitals, with applications to the Hückel method, to ligand field theory, and to the Woodward-Hoffmann rules. Many university level textbooks on physical chemistry, quantum chemistry, spectroscopy and inorganic chemistry discuss symmetry. Another framework on a larger scale is the use of crystal systems to describe crystallographic symmetry in bulk materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octahedral Molecular Geometry
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 Wern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahedral Molecular Geometry
In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1(−) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane () as well as its heavier analogues. Methane and other perfectly symmetrical tetrahedral molecules belong to point group Td, but most tetrahedral molecules have lower symmetry. Tetrahedral molecules can be chiral. Tetrahedral bond angle The bond angle for a symmetric tetrahedral molecule such as CH4 may be calculated using the dot product of two vectors. As shown in the diagram, the molecule can be inscribed in a cube with the tetravalent atom (e.g. carbon) at the cube centre which is the origin of coordinates, O. The four monovalent atoms (e.g. hydrogens) are at four corners of the cube (A, B, C, D) chosen so that no two atoms are at adjacent corners linked by only one cube edge. If the edge length of the cube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chem
Chem may refer to: * Chemistry practical waali mam *Chemistry *Chemical * ''Chem'' (journal), a scientific journal published by Cell Press *Post apocalyptic slang for "drugs", medicinal or otherwise in the Fallout video game series. In Ancient Egyptian usage: * ''Khem'' (also spelt ''Chem''), the Egyptian word for "black" * Min (god), in the past erroneously named ''Khem'' CHEM may refer to : *A metabolic panel: for instance, CHEM-7, which is the basic metabolic panel *CHEM-DT CHEM-DT is the TVA owned-and-operated television station in Trois-Rivières, Quebec, Canada. It broadcasts a high-definition digital signal on VHF channel 8 from a transmitter on Rue Principale in Notre-Dame-du-Mont-Carmel. Owned by the Grou ..., a Canadian television channel See also * Chemo (other) * Kemi, a place in Finland {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water-gas Shift Reaction
Water gas is a kind of fuel gas, a mixture of carbon monoxide and hydrogen. It is produced by "alternately hot blowing a fuel layer okewith air and gasifying it with steam". The caloric yield of this is about 10% of a modern syngas plant. Further making this technology unattractive, its precursor coke is expensive, whereas syngas uses cheaper precursor, mainly methane from natural gas. Production Synthesis gas is made by passing steam over a red-hot carbon fuel such as coke: : (ΔH = +131 kJ/mol) The reaction is endothermic, so the fuel must be continually re-heated to maintain the reaction. To do this, an air stream, which alternates with the vapor stream, is introduced to combust some of the carbon: : (ΔH = -393 kJ/mol) Theoretically, to make 6 L of water gas, 5 L of air is required. Alternatively, to prevent contamination with nitrogen, energy can be provided by using pure oxygen to burn carbon into carbon monoxide. : (ΔH = -221 kJ/mol) In this case, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
