|
Seleninyl Fluoride
Seleninyl fluoride is an oxyfluoride of selenium with the chemical formula SeOF2. Preparation Seleninyl fluoride can be produced by the reaction of selenium oxychloride and potassium fluoride. :2 KF + SeOCl2 → 2 KCl + SeOF2 It can also be produced by the reaction of selenium tetrafluoride with water or selenium dioxide. :SeF4 + H2O → SeOF2 + 2 HF :SeF4 + SeO2 → 2 SeOF2 The reaction of selenium dioxide and sulfur tetrafluoride also produces seleninyl fluoride. :SeO2 + SF4 → SeOF2 + SOF2 Reactions Seleninyl fluoride reacts with xenon difluoride to form Xe(OSeF5)2. :3 XeF2 + 2 SeOF2 → Xe(OSeF5)2 + 2 Xe It reacts with fluorine gas and potassium fluoride Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare m ... to form pentafluoroselenium hypofluorite. :SeOF2 + KF → K+ eOF3sup>- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Oxychloride
Selenium oxydichloride is the inorganic compound with the formula SeOCl2. It is a colorless liquid. With a high dielectric constant (55) and high specific conductance, it is an attractive solvent. Structurally, it is a close chemical relative of thionyl chloride SOCl2, being a pyramidal molecule. Preparation and reactions Selenium oxydichloride can be prepared by several methods, and a common one involves the conversion of selenium dioxide to dichloroselenious acid followed by dehydration: :SeO2 + 2 HCl → Se(OH)2Cl2 :Se(OH)2Cl2 → SeOCl2 + H2O The original synthesis involved the redistribution reaction of selenium dioxide and selenium tetrachloride. The compound hydrolyzes readily to form hydrogen chloride and selenium dioxide. See also * Selenium oxybromide SeOBr2 * Selenous acid Selenous acid (or selenious acid) is the chemical compound with the formula . Structurally, it is more accurately described by . It is the principal oxoacid of selenium; the other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Oxybromide
Selenium oxybromide ( Se O Br2) is a selenium oxohalide chemical compound. Preparation Selenium oxybromide can be prepared through the reaction of selenium dioxide and selenium tetrabromide. Selenium and selenium dioxide are reacted with bromine to form selenium monobromide and selenium tetrabromide. Dissolving the selenium dioxide in the tetrabromide will produce the oxybromide. :2 Se + Br2 → Se2Br2 :Se2Br2 + 3 Br2 → 2 SeBr4 :SeBr4 + SeO2 → 2 SeOBr2 Structure Evidence from infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ... and polarized Raman spectroscopy suggests that selenium oxybromide adopts a pyramidal molecular geometry with ''C''s symmetry, like other chalcogen(IV) oxohalides such as thionyl bromide () and selenium oxydichloride (). Properties Selenium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thionyl Fluoride
Thionyl fluoride is the inorganic compound with the formula . This colourless gas is mainly of theoretical interest, but it is a product of the degradation of sulfur hexafluoride, an insulator in electrical equipment. The molecule adopts a distorted pyramidal structure, with Cs symmetry. The S-O and S-F distances are 1.42 and 1.58 Å, respectively. The O-S-F and F-S-F angles are 106.2 and 92.2°, respectively. Thionyl chloride and thionyl bromide have similar structures, although these compounds are liquid at room temperature. Mixed halides are also known, such as SOClF, thionyl chloride fluoride. Synthesis and reactions Thionyl fluoride can be produced by the reaction of thionyl chloride with fluoride sources such as antimony trifluoride Antimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swarts' reagent, is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid. As well as some industrial app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Oxyfluoride
In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), chlorine (Cl), bromine (Br), and/or iodine (I). The element A may be a main group element, a transition element or an actinide. The term ''oxohalide'', or ''oxyhalide'', may also refer to minerals and other crystalline substances with the same overall chemical formula, but having an ionic structure. Synthesis Oxohalides can be seen as compounds intermediate between oxides and halides. There are three general methods of synthesis: *Partial oxidation of a halide: *:2 PCl3 + O2 -> 2 POCl3 **In this example, the oxidation state increases by two and the electrical charge is unchanged. *Partial halogenation of an oxide: *:2 V2O5 + 6 Cl2 + 3 C -> 4 VOCl3 + 3 CO2 *Oxide replacement: *: rO42- + 2 Cl- + 4 H+ -> CrO2Cl2 + 4 H2O In addition, various o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It seldom occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium – from Greek ( 'Moon') – was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Fluoride
Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare mineral carobbiite. Solutions of KF will etch glass due to the formation of soluble fluorosilicates, although HF is more effective. Preparation Potassium fluoride is prepared by dissolving potassium carbonate in hydrofluoric acid. Evaporation of the solution forms crystals of potassium bifluoride. The bifluoride on heating yields potassium fluoride: : K2CO3 + 4HF -> 2KHF2 + CO2 ^ + H2O : KHF2 -> KF + HF ^ Platinum or heat resistant plastic containers are often used for these operations. Potassium chloride converts to KF upon treatment with hydrogen fluoride. In this way, potassium fluoride is recyclable. Crystalline properties KF crystallizes in the cubic NaCl crystal structure. The lattice parameter at room temperature is 0.266 nm. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Tetrafluoride
Selenium tetrafluoride ( Se F4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas. Synthesis The first reported synthesis of selenium tetrafluoride was by Paul Lebeau in 1907, who treated selenium with fluorine: :Se + 2 F2 → SeF4 A synthesis involving more easily handled reagents entails the fluorination of selenium dioxide with sulfur tetrafluoride: :SF4 + SeO2 → SeF4 + SO2 An intermediate in this reaction is seleninyl fluoride (SeOF2). Other methods of preparation include fluorinating elemental selenium with chlorine trifluoride: :3 Se + 4 ClF3 → 3 SeF4 + 2 Cl2 Structure and bonding Selenium in SeF4 has an oxidation state of +4. Its shape in the gaseous phase is similar to that of SF4 ... [...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] |
Selenium Dioxide
Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. Properties Solid SeO2 is a one-dimensional polymer, the chain consisting of alternating selenium and oxygen atoms. Each Se atom is pyramidal and bears a terminal oxide group. The bridging Se-O bond lengths are 179 pm and the terminal Se-O distance is 162 pm.Handbook of Chalcogen Chemistry: New Perspectives in Sulfur, Selenium and Tellurium, Franceso A. Devillanova, Royal Society of Chemistry, 2007, The relative stereochemistry at Se alternates along the polymer chain (syndiotactic). In the gas phase selenium dioxide is present as dimers and other oligomeric species, at higher temperatures it is monomeric. The monomeric form adopts a bent structure very similar to that of sulfur dioxide with a bond length of 161 pm. The dimeric form has been isolated in a low temperature argon matrix and vibrational spectra indicate that it has a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Tetrafluoride
Sulfur tetrafluoride is the chemical compound with the formula S F4. It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries. Structure Sulfur in SF4 is in the formal +4 oxidation state. Of sulfur's total of six valence electrons, two form a lone pair. The structure of SF4 can therefore be anticipated using the principles of VSEPR theory: it is a see-saw shape, with S at the center. One of the three equatorial positions is occupied by a nonbonding lone pair of electrons. Consequently, the molecule has two distinct types of F ligands, two axial and two equatorial. The relevant bond distances are = 164.3 pm and = 154.2 pm. It is typical for the axial ligands in hypervalent molecules to be bonded less strongly. In c ... [...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] |
.svg "Click for more on -> Water")
