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Samarium Tribromide
Samarium(III) bromide is a crystalline compound of one samarium and three bromine atoms with the chemical formula of SmBr3. Samarium(III) bromide is a dark brown powder at room temperature. The compound has a crystal structure isotypic to that of plutonium(III) bromide. Preparation SmBr3·6H2O can be crystallized by dissolving samarium oxide in 40% hydrobromic acid. The hydrate and ammonium chloride are heated in a vacuum to obtain the anhydrous form of samarium(III) bromide.林平娣, 吴国庆无水三溴化钐和三溴化镱的制备 化学试剂, 1991(1):13-14. Other compounds Samarium(III) bromide forms some compounds with hydrazine, such as SmBr3·3N2H4·H2O which is a pale yellow needle-shaped crystal that is soluble in water and ethanol but insoluble in 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 cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samarium(III) Fluoride
Samarium(III) fluoride ( Sm F3) is a slightly hygroscopic solid fluoride. At room temperature, it has orthorhombic structure with space group ''Pnma'' – β-YF3 type with lattice constants ''a'' = 666,9 pm, ''b'' = 705,9 pm, ''c'' = 440,5 pm. Above 495 °C, it has the rhombohedral LaF3 structure (space group ''P3cl'') – with lattice constants ''a'' = 707, ''c'' = 724 pm.K Rotereau et al.: ''The high-temperature phase transition in samarium fluoride, SmF3: structural and vibrational investigation'', J. Phys.: Condens. Matter, 1998, 10, 1431–1446, . Conditions/substances to avoid are: open flame A flame (from Latin '' flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density they ..., moisture, strong acids. References Fluorides Samarium compounds Lanthanide halides {{inorganic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samarium(III) Chloride
Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl3.6H2O. The compound has few practical applications but is used in laboratories for research on new compounds of samarium. Structure Like several related chlorides of the lanthanides and actinides, SmCl3 crystallises in the UCl3 motif. The Sm3+ centres are nine-coordinate, occupying trigonal prismatic sites with additional chloride ligands occupying the three square faces. Preparation and reactions SmCl3 is prepared by the " ammonium chloride" route, which involves the initial synthesis of (NH4)2 mCl5 This material can be prepared from the common starting materials at reaction temperatures of 230 °C from samarium oxide: ::10 NH4Cl + Sm2O3 → 2 (NH4)2 mCl5 + 6 NH3 + 3 H2O The pentachloride is then heated to 350-400 °C resulting in evolution of ammonium chloride and leaving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samarium(II) Bromide
Samarium(II) bromide is an inorganic compound with the chemical formula . It is a brown solid that is insoluble in most solvents but degrades readily in air. Structure In the gas phase, is a bent molecule with Sm–Br distance 274.5 pm and bond angle 131±6°. History Samarium(II) bromide was first synthesized in 1934 by P. W. Selwood, when he reduced samarium tribromide (SmBr3) with hydrogen (H2). Kagan also synthesized it by converting samarium(III) oxide (Sm2O3) to SmBr3 and then reducing with a lithium dispersion in THF. Robert A. Flowers synthesized it by adding two equivalent of lithium bromide (LiBr) to samarium diiodide (SmI2) in tetrahydrofuran. Namy managed to synthesize it by mixing tetrabromoethane (C2H2Br4) with samarium metal, and Hilmerson found that heating the tetrabromoethane or samarium greatly improved the production of samarium(II) bromide. Reactions Samarium(II) bromide has reducing properties reminiscent of the more commonly used samarium diiodide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samarium
Samarium is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide. The last compound is a common reducing agent in chemical synthesis. Samarium has no significant biological role, and some samarium salts are slightly toxic. Samarium was discovered in 1879 by French chemist Paul-Émile Lecoq de Boisbaudran and named after the mineral samarskite from which it was isolated. The mineral itself was named after a Russian mine official, Colonel Vassili Samarsky-Bykhovets, who thus became the first person to have a chemical element named after him, albeit indirectly. Though classified as a rare-earth element, samarium is the 40th most abundant element in Earth's crust and more common than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek (bromos) meaning "stench", referring to its sharp and pungent smell. Elemental bromine is very reactive and thus does not occur as a native element in nature but it occurs in colourless soluble crystalline mineral halide salts, analogous to table salt. In fact, bromine and all the halogens are so reactive that they form bonds in pairs—never in single atoms. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its accumulation in the oceans. Commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutonium(III) Bromide
Plutonium(III) bromide is an inorganic salt of bromine and plutonium with the formula PuBr3. This radioactive green solid has few uses, however its crystal structure is often used as a structural archetype in crystallography. Crystal structure The PuBr3 crystal structure was first published in 1948 by William Houlder Zachariasen. The compound forms orthorhombic crystals, a type of square antiprism, within which the Pu atoms adopt an 8-coordinate bicapped trigonal prismatic arrangement. Its Pearson symbol is oS16 with the corresponding space group No. 63 (in International Union of Crystallography classification) or Cmcm (in Hermann–Mauguin notation In geometry, Hermann–Mauguin notation is used to represent the symmetry elements in point groups, plane groups and space groups. It is named after the German crystallographer Carl Hermann (who introduced it in 1928) and the French mineralogis ...). The majority of trivalent chloride and bromide salts of lanthanide and acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samarium Oxide
Samarium(III) oxide ( Sm2 O3) is a chemical compound. Samarium oxide readily forms on the surface of samarium metal under humid conditions or temperatures in excess of 150°C in dry air. Similar to rust on metallic iron, this oxide layer spalls off the surface of the metal, exposing more metal to continue the reaction. The oxide is commonly white to off yellow in color and is often encountered as a highly fine dust like powder. Uses Samarium(III) oxide is used in optical and infrared absorbing glass to absorb infrared radiation. Also, it is used as a neutron absorber in control rods for nuclear power reactors. The oxide catalyzes the dehydration and dehydrogenation of primary and secondary alcohols. Another use involves preparation of other samarium salts. Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, Preparations Samarium(III) oxide may be prepared by two methods: 1. thermal decomposition of samarium(III) carbonate, hydroxide, nitrate, oxalate or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrobromic Acid
Hydrobromic acid is a strong acid formed by dissolving the diatomic molecule hydrogen bromide (HBr) in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at and contains 47.6% HBr by mass, which is 8.77 mol/L. Hydrobromic acid has a p''K''a of −9, making it a stronger acid than hydrochloric acid, but not as strong as hydroiodic acid. Hydrobromic acid is one of the strongest mineral acids known. Uses Hydrobromic acid is mainly used for the production of inorganic bromides, especially the bromides of zinc, calcium, and sodium. It is a useful reagent for generating organobromine compounds. Certain ethers are cleaved with HBr. It also catalyzes alkylation reactions and the extraction of certain ores. Industrially significant organic compounds prepared from hydrobromic acid include allyl bromide, tetrabromobis(phenol), and bromoacetic acid. HBr almost uniquely participates in anti-Markovnikov hydrohalogenation of alkenes. The resulting 1-bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a ''perfect'' vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure. The Latin term ''in vacuo'' is used to describe an object that is surrounded by a vacuum. The ''quality'' of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. But hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine hydrate (). Hydrazine is mainly used as a foaming agent in preparing polymer foams, but applications also include its uses as a precursor to polymerization catalysts, pharmaceuticals, and agrochemicals, as well as a long-term storable propellant for in-space spacecraft propulsion. Additionally, hydrazine is used in various rocket fuels and to prepare the gas precursors used in air bags. Hydrazine is used within both nuclear and conventional electrical power plant steam cycles as an oxygen scavenger to control concentrations of dissolved oxygen in an effort to reduce corrosion. the world hydrazine hydrate market amounted to $350 million. About two million tons of hydrazine hydrate were used in foam blowing agents in 2015. Hydrazines r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which 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, H2O, 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°. "Water" is also the name of the liquid state of H2O at standard temperature and pressure. A number of natural states of water exist. 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 may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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