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Beryllocene
Beryllocene is an organoberyllium compound with the chemical formula Be(C5H5)2, first prepared in 1959. The colorless substance can be crystallized from petroleum ether in the form of white needles at −60 °C and decomposes quickly upon contact with atmospheric oxygen and water. Preparation Beryllocene can be prepared by reacting beryllium chloride and sodium cyclopentadienide in benzene or diethyl ether: :\mathrm Properties Physical In contrast to the uncharged metallocenes of the transition metals V, Cr, Fe, Co, Ni, Ru and Os, which have a strictly symmetrical and therefore dipoleless structure, beryllocene has an electric dipole moment of 2.46 Debye (in benzene), or 2.24 Debye (in cyclohexane), indicating asymmetry of the molecule. In the IR spectrum there are signals at 1524, 1610, 1669, 1715 and 1733 cm−1, which also indicate that the structure does correspond to that of ferrocene. In contrast, the nuclear magnetic resonance spectrum shows only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium Compounds
Beryllium is a chemical element; it has symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Gemstones high in beryllium include beryl ( aquamarine, emerald, red beryl) and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen. In structural applications, the combination of high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium
Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Gemstones high in beryllium include beryl (Aquamarine (gemstone), aquamarine, emerald, red beryl) and chrysoberyl. It is a Abundance of the chemical elements#Universe, relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen. In structural applications, the combination of high flexural ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoberyllium Compound
Organoberyllium chemistry involves the synthesis and properties of organometallic compounds featuring the group 2 alkaline earth metal beryllium (Be). The area remains less developed relative to the chemistry of other main-group elements, because Be compounds are toxic and few applications have been found. Structure Homoleptic compounds The coordination number of Be in organoberyllium compounds ranges from two to four. Dimethylberyllium and dimethylmagnesium adopts the same structure. Diethylberyllium, however, does not structurally resemble diethylmagnesium (which has the same structure as dimethylmagnesium). This contrast is attributed to the small size of Be relative to its heavier congener Mg: Be is one of the smallest atoms on the periodic table. Dineopentylberyllium and many other dialkyl derivatives has been reported. The phenyl derivative is represented by trimeric Be3Ph6. A terphenyl derivative is known. With bulky aryl ligands three-coordination is observed, see . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arne Haaland
Arne Haaland (15 February 1936 – 13 October 2023) was a Norwegian chemist. He took the dr. philos. degree at the University of Oslo in 1969 and was an associate professor in chemistry at the University of Oslo from 1964 to 1984, and then professor until his retirement. He was a fellow of the Norwegian Academy of Science and Letters. Haaland ran a laboratory for gas electron diffraction. He, his co-workers and colleagues determined the structures of umpteen important chemical compounds in the gas phase. His main field of research was the organometallic 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 so ... compounds. The list of such structure determinations includes the controversially debated beryllocene, dibenzene chromium, ferrocene, the structure of the phosphorus oxides P4O1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food energy or organic micronutrients. Its chemical formula, , indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. In liquid form, is also called "water" at standard temperature and pressure. Because Earth's environment is relatively close to water's triple point, water exists on Earth as a solid, a liquid, and a gas. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Magnetic Resonance Spectrum
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic field. This re-orientation occurs with absorption of electromagnetic radiation in the radio frequency region from roughly 4 to 900 MHz, which depends on the isotopic nature of the nucleus and increases proportionally to the strength of the external magnetic field. Notably, the resonance frequency of each NMR-active nucleus depends on its chemical environment. As a result, NMR spectra provide information about individual functional groups present in the sample, as well as about connections between nearby nuclei in the same molecule. As the NMR spectra are unique or highly characteristic to individual compounds and functional groups, NMR spectroscopy is one of the most important methods to identify molecular structures, particularly of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallocenes
A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metallic element, metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride or vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalysis, catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to [Cp2ZrCH3]+ catalyze Ziegler–Natta catalyst, olefin polymerization. Some metallocenes consist of metal plus two cyclooctatetraenide anions (, abbreviated cot2−), namely the lanthanocenes and the actinocenes (uranocene and others). Metallocenes are a subset of a broader class of compounds called sandwich compounds. In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromaticity, aromatically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruses and bacteria. Most carcinogens act by creating mutations in DNA that disrupt a cell's normal processes for regulating growth, leading to uncontrolled cellular proliferation. This occurs when the cell's DNA repair processes fail to identify DNA damage allowing the defect to be passed down to daughter cells. The damage accumulates over time. This is typically a multi-step process during which the regulatory mechanisms within the cell are gradually dismantled allowing for unchecked cellular division. The specific mechanisms for carcinogenic activity is unique to each agent and cell type. Carcinogens can be broadly categorized, however, as activation-dependent and activation-independent which relate to the agent's ability to engage dir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron(II) Chloride
Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions. Production Hydrated forms of ferrous chloride are generated by treatment of wastes from steel production with hydrochloric acid. Such solutions are designated "spent acid," or "pickle liquor" especially when the hydrochloric acid is not completely consumed: :Fe + 2 HCl → FeCl2 + H2 The production of ferric chloride involves the use of ferrous chloride. Ferrous chloride is also a byproduct from the production of titanium, since some titanium ores contain iron.Egon Wildermuth, Hans Stark, Gabriele Friedrich, Franz Ludw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrocene
Ferrocene is an organometallic chemistry, organometallic compound with the formula . The molecule is a Cyclopentadienyl complex, complex consisting of two Cyclopentadienyl anion, cyclopentadienyl rings sandwiching a central iron atom. It is an orange solid with a camphor-like odor that Sublimation (phase transition), sublimes above room temperature, and is soluble in most organic solvents. It is remarkable for its stability: it is unaffected by air, water, strong bases, and can be heated to 400 °C without decomposition. In oxidizing conditions it can reversibly react with strong acids to form the ferrocenium cation . Ferrocene and the ferrocenium cation are sometimes abbreviated as Fc and respectively. The first reported synthesis of ferrocene was in 1951. Its unusual stability puzzled chemists, and required the development of new theory to explain its formation and bonding. The discovery of ferrocene and its many Structural analog, analogues, known as metallocenes, sparke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesocene
Magnesocene, also known as bis(cyclopentadienyl)magnesium(II) and sometimes abbreviated as MgCp2, is an organometallic compound with the formula Mg(η5-C5H5)2. It is white powder or crystals. It is an example of an s-block Main-group element, main group sandwich compound, structurally related to the d-block element metallocenes, and consists of a central magnesium atom sandwiched between two Cyclopentadienyl complex, cyclopentadienyl rings. Properties Magnesocene is a white solid at room temperature. It has a melting point of 176 °C, though at atmospheric pressures it Sublimation (phase transition), sublimes at 100 °C. Unlike ferrocene, magnesocene displays slight dissociation and subsequent ion association in polar, electron-donating solvents (such as ether and THF). : : : While ferrocene is stable at ambient conditions, magnesocene decomposes rapidly on exposure to oxygen or moisture, and as such must be synthesized and stored under inert conditions. Structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
