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Selenium Dioxydifluoride
Selenoyl fluoride, selenoyl difluoride, selenium oxyfluoride, or selenium dioxydifluoride is a chemical compound with the formula SeO2F2. Structure The shape of the molecule is a distorted tetrahedron with the O-Se-O angle being 126.2°, the O-Se-F angle being 108.0° and F-Se-F being 94.1°. The Se-F bond length is 1.685 Å and the selenium to oxygen bond is 1.575 Å long. Formation Selenoyl fluoride can be formed by the action of warm fluorosulfonic acid on barium selenate or selenic acid. SeO3 + SeF4 can give this gas along with other oxyfluorides. Reactions Selenoyl fluoride is more reactive than its analogon sulfuryl fluoride. It is easier to hydrolyse and to reduce. It may react violently upon contact with ammonia. Selenoyl fluoride reacting with xenon difluoride Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decompo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Konrad Seppelt
Konrad Seppelt (born September 2, 1944 in Leipzig) is a academic author, professor and former vice president of the Free University Berlin. Publications Popular publications Cutting Edge Konrad Seppelt, The (London) Times Higher Education Supplement, November 10, 2000, p. 24. The Future of Chemistry ... Editorial, Angew. Chem. Int. Ed. 2004, 43, 3618 –3620 * ScienceIsolation and structural and electronic characterization of salts of the decamethylferrocene dication.August 2016 12;353(6300):678-82 * ScienceXenon as a complex ligand: the tetra xenono Gold(II) cation in AuXe42+(Sb2F11−)2. 2000 Oct 6;290(5489)117-8. * ScienceResponse: Structure of W(CH3)6. 1996 Apr 12;272(5259):182b-3b. Scientific publications A random selection of Prof Seppelt's publications: * * *Seppelt, K. “Selenoyl difluoride” Inorganic Syntheses, 1980, volume XX, pp. 36–38. . * *Seppelt, K., Pfennig, V. ''Science'' 1996, 271, 626-8. *Kleinhenz, S., Pfennig, V., Seppelt, K. ''Chem. Eur. J.'' 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuryl Fluoride
Sulfuryl fluoride (also spelled ''sulphuryl fluoride'') is an inorganic compound with the chemical formula, formula SO2F2. It is an easily condensed gas and has properties more similar to sulfur hexafluoride than sulfuryl chloride, being resistant to hydrolysis even up to 150 °C. It is neurotoxic and a potent greenhouse gas, but is widely used as a fumigant insecticide to control termites. Structure, preparation, reactions The molecule is tetrahedral with C2v symmetry point group, symmetry. The S-O distance is 140.5 pm, S-F is 153.0 pm. As predicted by VSEPR, the O-S-O angle is more open than the F-S-F angle, 124° and 97°, respectively. One synthesis begins with the preparation of potassium fluorosulfite: :SO2 + KF → KSO2F This salt is then chlorinated to give sulfuryl chloride fluoride: :KSO2F + Cl2 → SO2ClF + KCl Further heating at 180 °C of potassium fluorosulfite with the sulfuryl chloride fluoride gives the desired product: :SO2ClF + KSO2F → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Hexafluoride
Selenium hexafluoride is the inorganic compound with the formula SeF6. It is a very toxic colourless gas described as having a "repulsive" odor. It is not widely encountered and has no commercial applications. Structure, preparation, and reactions SeF6 has octahedral molecular geometry with an Se−F bond length of 168.8 pm. In terms of bonding, it is hypervalent. SeF6 can be prepared from the elements. It also forms by the reaction of bromine trifluoride (BrF3) with selenium dioxide. The crude product can be purified by sublimation. The relative reactivity of the hexafluorides of S, Se, and Te follows the order TeF6 > SeF6 > SF6, the latter being completely inert toward hydrolysis until high temperatures. SeF6 also resists hydrolysis. The gas can be passed through 10% NaOH or KOH without change, but reacts with gaseous ammonia at 200 °C. Safety Although selenium hexafluoride is quite inert and slow to hydrolyze, it is toxic even at low concentrations, especi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Trioxide
Selenium trioxide is the inorganic compound with the formula Se O3. It is white, hygroscopic solid. It is also an oxidizing agent and a Lewis acid. It is of academic interest as a precursor to Se(VI) compounds.Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemistry'', Elsevier Preparation Selenium trioxide is difficult to prepare because it is unstable with respect to the dioxide: :2 SeO3 → 2 SeO2 + O2 It has been generated in a number of ways despite the fact that the dioxide does not combust under normal conditions. One method entails dehydration of anhydrous selenic acid with phosphorus pentoxide at 150–160 °C. Another method is the reaction of liquid sulfur trioxide with potassium selenate. :SO3 + K2SeO4 → K2SO4 + SeO3 Reactions In its chemistry SeO3 generally resembles sulfur trioxide, SO3, rather than tellurium trioxide, TeO3. At 120 °C SeO3 reacts with selenium dioxide to form the Se(VI)-Se(IV) compound diselenium pentaoxide:Z. Žák " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ''plus'' (+) and ''minus'' (−) signs. These are limited to a single typographic line of symbols, which may include Subscript and superscript, subscripts and superscripts. A chemical formula is not a chemical nomenclature, chemical name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are generally more limited in power than chemical names and structural formulae. The simplest types of chemical formulae are called ''empirical formulae'', which use letters and numbers ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorosulfonic Acid
Fluorosulfuric acid (IUPAC name: sulfurofluoridic acid) is the inorganic compound with the chemical formula HSO3F. It is one of the strongest acids commercially available. It is a tetrahedral molecule and is closely related to sulfuric acid, H2SO4, substituting a fluorine atom for one of the hydroxyl groups. It is a colourless liquid, although commercial samples are often yellow.Erhardt Tabel, Eberhard Zirngiebl, Joachim Maas "Fluorosulfuric Acid" in "Ullmann's Encyclopedia of Industrial Chemistry" 2005, Wiley-VCH, Weinheim. Chemical properties Fluorosulfuric acid is a free-flowing colorless liquid. It is soluble in polar organic solvents (e.g. nitrobenzene, acetic acid, and ethyl acetate), but poorly soluble in nonpolar solvents such as alkanes. Reflecting its strong acidity, it dissolves almost all organic compounds that are even weak proton acceptors. HSO3F hydrolyzes slowly to hydrogen fluoride (HF) and sulfuric acid. The related triflic acid () retains the high acidity of HSO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barium Selenate
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. The most common minerals of barium are baryte (barium sulfate, BaSO4) and witherite (barium carbonate, BaCO3). The name ''barium'' originates from the alchemical derivative "baryta", from Greek (), meaning 'heavy'. ''Baric'' is the adjectival form of barium. Barium was identified as a new element in 1774, but not reduced to a metal until 1808 with the advent of electrolysis. Barium has few industrial applications. Historically, it was used as a getter for vacuum tubes and in oxide form as the emissive coating on indirectly heated cathodes. It is a component of YBCO (high-temperature superconductors) and electroceramics, and is added to steel and cast iron to reduce the size of carbon grains within the microstructure. Barium compounds are ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenic Acid
Selenic acid is the inorganic compound with the formula . It is an oxoacid of selenium, and its structure is more accurately described as . It is a colorless compound. Although it has few uses, its derivative sodium selenate is used in the production of glass and animal feeds.Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. . Structure and bonding The molecule is tetrahedral, as predicted by VSEPR theory. The Se–O bond length is 161 pm. In the solid state, it crystallizes in an orthorhombic structure. Preparation It is prepared by oxidising selenium compounds in lower oxidation states. One method involves the oxidation of selenium dioxide with hydrogen peroxide: : Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method. Instead, selenic acid may also be prepared by the oxidation of selenous acid () with halogens, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuryl Fluoride
Sulfuryl fluoride (also spelled ''sulphuryl fluoride'') is an inorganic compound with the chemical formula, formula SO2F2. It is an easily condensed gas and has properties more similar to sulfur hexafluoride than sulfuryl chloride, being resistant to hydrolysis even up to 150 °C. It is neurotoxic and a potent greenhouse gas, but is widely used as a fumigant insecticide to control termites. Structure, preparation, reactions The molecule is tetrahedral with C2v symmetry point group, symmetry. The S-O distance is 140.5 pm, S-F is 153.0 pm. As predicted by VSEPR, the O-S-O angle is more open than the F-S-F angle, 124° and 97°, respectively. One synthesis begins with the preparation of potassium fluorosulfite: :SO2 + KF → KSO2F This salt is then chlorinated to give sulfuryl chloride fluoride: :KSO2F + Cl2 → SO2ClF + KCl Further heating at 180 °C of potassium fluorosulfite with the sulfuryl chloride fluoride gives the desired product: :SO2ClF + KSO2F → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is both caust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon Difluoride
Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwise stable in storage. Xenon difluoride is a dense, colourless crystalline solid. It has a nauseating odour and low vapor pressure. Structure Xenon difluoride is a linear molecule with an Xe–F bond length of in the vapor stage, and 200 pm in the solid phase. The packing arrangement in solid shows that the fluorine atoms of neighbouring molecules avoid the equatorial region of each molecule. This agrees with the prediction of VSEPR theory, which predicts that there are 3 pairs of non-bonding electrons around the equatorial region of the xenon atom. At high pressures, novel, non-molecular forms of xenon difluoride can be obtained. Under a pressure of ~50 GPa Grading in education is the process of applying standardized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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