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Neptunocene
Neptunocene, Np(C8H8)2, is an organoneptunium compound composed of a neptunium atom sandwiched between two cyclooctatetraenide (COT2-) rings. As a solid it has a dark brown/red colour but it appears yellow when dissolved in chlorocarbons, in which it is sparingly soluble. The compound is quite air-sensitive. It was one of the first organoneptunium compounds to be synthesised, and is a member of the actinocene family of actinide-based metallocenes. Structure The sandwich structure of neptunocene has been determined by single crystal XRD. The COT2- rings are found to be planar with 8 equivalent C–C bonds of 1.385 Å length, and sit parallel in an eclipsed conformation. The Np–COT distance (to the ring centroid) is 1.909 Å and the individual Np–C distances are 2.630 Å. Neptunocene assumes a monoclinic crystal structure (''P''21/''n'' space group) which is isomorphous to uranocene and thorocene but not to plutonocene. Synthesis and properties Neptunocene was first synt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neptunium
Neptunium is a chemical element with the Symbol (chemistry), symbol Np and atomic number 93. A radioactivity, radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotrope, allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. It is Radioactive decay, radioactive, radiation poisoning, poisonous, pyrophoricity, pyrophoric, and capable of accumulating in bones, which makes the handling of neptunium dangerous. Although many false claims of its discovery were made over the years, the element was first synthesized by Edwin McMillan and Philip H. Abelson at the Berkeley Radiation Laboratory in 1940. Since then ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neptunium(IV) Chloride
Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. It is radioactive, poisonous, pyrophoric, and capable of accumulating in bones, which makes the handling of neptunium dangerous. Although many false claims of its discovery were made over the years, the element was first synthesized by Edwin McMillan and Philip H. Abelson at the Berkeley Radiation Laboratory in 1940. Since then, most neptunium has been and still is produced by neutron irradiation of uranium in nuclear reactors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neptunium Compounds
Neptunium compounds are compounds containg the element neptunium (Np). Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds. Solution chemistry When it is in an aqueous solution, neptunium can exist in any of its five possible oxidation states (+3 to +7) and each of these show a characteristic color.Np(II), (III) and (IV) have been observed, see The stability of each oxidation state is strongly dependent on various factors, such as the presence of oxidizing or reducing agents, pH of the solution, presence of coordination complex-forming ligands, and even the concentration of ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoactinide Compounds
Organoactinide chemistry is the science exploring the properties, structure and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond. Like most organometallic compounds, the organoactinides are air sensitive and need to be handled using the appropriate methods. Organometallic complexes with σ-bonding Most common organoactinide complexes involve π-bonding with ligands such as cyclopentadienyl, but there are a few exceptions with σ-bonding, namely in thorium and uranium chemistry as these are the most easily handleable elements of this group. Alkyl and aryl compounds Attempts to synthesize uranium alkyls were first made during the Manhattan project by Henry Gilman, inspired by the volatility of main group organometallics. However he noticed that these compounds tend to be highly unstable. Marks and Seyam attempted to synthesize them from UCl using organolithium reagents, but these decomposed quickly. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutonocene
Plutonocene, Pu(C8H8)2, is an organoplutonium compound composed of a plutonium atom sandwiched between two cyclooctatetraenide (COT2-) rings. It is a dark red, very air-sensitive solid that is sparingly soluble in toluene and chlorocarbons. Plutonocene is a member of the actinocene family of metallocenes incorporating actinide elements in the +4 oxidation state. Compared to other actinocenes such as uranocene, plutonocene has been studied to a lesser degree since the 1980s due to the notable radiation hazard posed by the compound. Instead, it has mostly been the subject of theoretical studies relating to the bonding in the molecule. Structure and bonding The compound has been structurally characterised by single crystal XRD. The cyclooctatetraenide rings are eclipsed and assume a planar conformation with 8 equivalent C–C bonds of 1.41 Å length; the molecule possesses a centre of inversion at the position occupied by the plutonium atom. The Pu–COT distance (to the ring ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorocene
Actinocenes are a family of organoactinide compounds consisting of metallocenes containing elements from the actinide series. They typically have a sandwich structure with two dianionic cyclooctatetraenyl ligands (COT2-, which is ) bound to an actinide-metal center (An) in the oxidation state IV, resulting in the general formula An(C8H8)2. Characterised actinocenes The most studied actinocene is uranocene, U(C8H8)2, which in 1968 was the first member of this family to be synthesised and is still viewed as the archetypal example. Other actinocenes that have been synthesised are protactinocene (Pa(C8H8)2), thorocene (Th(C8H8)2), neptunocene (Np(C8H8)2), and plutonocene (Pu(C8H8)2). Especially the latter two, neptunocene and plutonocene, have not been extensively studied experimentally since the 1980s because of the radiation hazard they pose. Bonding The actinide-cyclooctatetraenyl bonding has been of interest for multiple theoretical studies. Computational chemistry methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinocene
Actinocenes are a family of organoactinide compounds consisting of metallocenes containing elements from the actinide series. They typically have a sandwich structure with two dianionic cyclooctatetraenyl ligands (COT2-, which is ) bound to an actinide-metal center (An) in the oxidation state IV, resulting in the general formula An(C8H8)2. Characterised actinocenes The most studied actinocene is uranocene, U(C8H8)2, which in 1968 was the first member of this family to be synthesised and is still viewed as the archetypal example. Other actinocenes that have been synthesised are protactinocene (Pa(C8H8)2), thorocene (Th(C8H8)2), neptunocene (Np(C8H8)2), and plutonocene (Pu(C8H8)2). Especially the latter two, neptunocene and plutonocene, have not been extensively studied experimentally since the 1980s because of the radiation hazard they pose. Bonding The actinide-cyclooctatetraenyl bonding has been of interest for multiple theoretical studies. Computational chemistry methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipotassium Cyclooctatetraenide
Dipotassium cyclooctatetraenide, sometimes abbreviated K2COT, is an organopotassium compound with the formula K2C8H8. It is a brown solid that is used as a precursor to cyclooctatetraenide complexes, such as uranocene (U(C8H8)2). Analogs of K2C8H8 are known with ring substituents, with different alkali metals, and with various complexants. Preparation and structure Potassium cyclooctatetraenide is formed by the reaction of cyclooctatetraene with potassium metal: :2 K + C8H8 → K2C8H8 The reaction entails 2-electron reduction of the polyene and is accompanied by a color change from colorless to brown. The structure of K2(diglyme)C8H8 has been characterized by X-ray crystallography of the derivatives with diglyme Diglyme, or bis(2-methoxyethyl) ether, is a solvent with a high boiling point. It is an organic compound which is the dimethyl ether of diethylene glycol. (The name ''diglyme'' is a portmanteau of ''diglycol methyl ether''.) It is a colorless li ... complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclooctatetraene
1,3,5,7-Cyclooctatetraene (COT) is an unsaturated derivative of cyclooctane, with the formula C8H8. It is also known as nnulene. This polyunsaturated hydrocarbon is a colorless to light yellow flammable liquid at room temperature. Because of its stoichiometric relationship to benzene, COT has been the subject of much research and some controversy. Unlike benzene, C6H6, cyclooctatetraene, C8H8, is not aromatic, although its dianion, (cyclooctatetraenide), is. Its reactivity is characteristic of an ordinary polyene, i.e. it undergoes addition reactions. Benzene, by contrast, characteristically undergoes substitution reactions, not additions. History 1,3,5,7-Cyclooctatetraene was initially synthesized by Richard Willstätter in Munich in 1905 using pseudopelletierine as the starting material and the Hofmann elimination as the key transformation: : Willstätter noted that the compound did not exhibit the expected aromaticity. Between 1939 and 1943, chemists throughout the US u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry group, symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Tetrachloride
Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVACR) is an organic compound with the chemical formula CCl4. It is a colourless liquid with a "sweet" smell that can be detected at low levels. It is practically incombustible at lower temperatures. It was formerly widely used in fire extinguishers, as a precursor to refrigerants and as a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride (including vapor) can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal. Properties In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a tetrahedron, tetrahedral configuration joined to a central carbon atom by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent. As the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm. History The compound was first isolated in 1837 through a distillation of pine oil by the Polish chemist Filip Walter, who named it ''rétinnaphte''. In 1841, French chemist Henri Étienne Sainte-Claire Deville isolated a hydrocarbon from balsam of Tolu (an aromatic extract from the tropical Colombian tree ''Myroxylon balsamum''), which Deville recognized as similar to Wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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