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Krypton Difluoride
Krypton difluoride, KrF2 is a chemical compound of krypton and fluorine. It was the first compound of krypton discovered. It is a volatile, colourless solid at room temperature. The structure of the KrF2 molecule is linear, with Kr−F distances of 188.9 pm. It reacts with strong Lewis acids to form salts of the KrF+ and Kr cations. The atomization energy of KrF2 (KrF2(g) → Kr(g) + 2 F(g)) is 21.9 kcal/mol, giving an average Kr–F bond energy of only 11 kcal/mol, the weakest of any isolable fluoride. In comparison, the dissociation of difluorine to atomic fluorine requires cleaving a F–F bond with a bond dissociation energy of 36 kcal/mol. Consequently, KrF2 is a good source of the extremely reactive and oxidizing atomic fluorine. It is thermally unstable, with a decomposition rate of 10% per hour at room temperature. The formation of krypton difluoride is endothermic, with a heat of formation (gas) of 14.4 ± 0.8 kcal/mol measured at 93 °C. Synthesis Krypton difluor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon Difluoride
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also used to search for hypothetical weakly interacting massive particles and as a propellant for ion thrusters in spacecraft. Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive x ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel Tetrafluoride
Nickel tetrafluoride is an inorganic compound with a chemical formula . Synthesis Nickel tetrafluoride is claimed to result from the reaction of (pentafluoroxenonium(IV) hexafluoronickelate(IV)) with and with . Chemical properties Nickel tetrafluoride is an extremely strong oxidizer. The oxidizing properties are enhanced in presence of Lewis acids in anhydrous HF. In terms of oxidizing power, it is comparable to krypton difluoride. It can oxidize bromine pentafluoride Bromine pentafluoride, Br F5, is an interhalogen compound and a fluoride of bromine. It is a strong fluorinating agent. BrF5 finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of BrF5 releases O2 for subs ... to hexafluorobromonium(VII) cation , potassium hexafluoroplatinate(V) to platinum(VI) fluoride . References {{Fluorides Nickel compounds Fluorides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorides
Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic, monatomic anion of fluorine, with the chemical formula (also written ), whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin. Fluoride is the simplest fluorine anion. In terms of charge and size, the fluoride ion resembles the hydroxide ion. Fluoride ions occur on Earth in several minerals, particularly fluorite, but are present only in trace quantities in bodies of water in nature. Nomenclature Fluorides include compounds that contain ionic fluoride and those in which fluoride does not dissociate. The nome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krypton Fluoride Laser
A krypton fluoride laser (KrF laser) is a particular type of excimer laser, which is sometimes (more correctly) called an exciplex laser. With its 248 nanometer wavelength, it is a deep ultraviolet laser which is commonly used in the production of semiconductor integrated circuits, industrial micromachining, and scientific research. The term excimer is short for 'excited dimer', while exciplex is short for 'excited complex'. An excimer laser typically contains a mixture of: a noble gas such as argon, krypton, or xenon; and a halogen gas such as fluorine or chlorine. Under suitably intense conditions of electromagnetic stimulation and pressure, the mixture emits a beam of coherent stimulated radiation as laser light in the ultraviolet range. KrF and ArF excimer lasers are widely incorporated into high-resolution photolithography machines, one of the critical tools required for microelectronic chip manufacturing in nanometer dimensions. Excimer laser lithographyJain, K. "Excimer La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Spin Resonance Spectroscopy
Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spins excited are those of the electrons instead of the atomic nuclei. EPR spectroscopy is particularly useful for studying metal complexes and organic radicals. EPR was first observed in Kazan State University by Soviet physicist Yevgeny Zavoisky in 1944, and was developed independently at the same time by Brebis Bleaney at the University of Oxford. Theory Origin of an EPR signal Every electron has a magnetic moment and spin quantum number s = \tfrac , with magnetic components m_\mathrm = + \tfrac or m_\mathrm = - \tfrac . In the presence of an external magnetic field with strength B_\mathrm , the electron's magnetic moment aligns itself either antiparallel ( m_\mathrm = - \tfrac ) or parallel ( m_\mathrm = + \tfrac ) to the field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver(III) Fluoride
Silver(III) fluoride, AgF3, is an unstable, bright-red, diamagnetic compound containing silver in the unusual +3 oxidation state. Its crystal structure is very similar to that of gold(III) fluoride: it is a polymer consisting of rectangular AgF4 units linked into chains by fluoro bridges. Preparation AgF3 can be prepared by treating a solution containing tetrafluoroargentate(III) ions in anhydrous hydrogen fluoride with boron trifluoride; the potassium tetrafluoroargentate(III) was prepared by heating a stoichiometric mix of potassium and silver nitrate in a sealed container filled with pressurised fluorine gas at 400C for 24 hours, twice. When dissolved in anhydrous HF, it decomposes spontaneously to Ag3F8 overnight at room temperature. The high-valence silver compounds described in the thesis are notable for their variety of colours: KAgF4 is bright orange, AgF3 bright red, AgFAsF6 is deep blue, Ag3F8 deep red-brown, and Pd(AgF4)2 is lime-green. Earlier preparations used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine Pentafluoride
Chlorine pentafluoride is an interhalogen compound with formula . This colourless gas is a strong oxidant that was once a candidate oxidizer for rockets. The molecule adopts a square pyramidal structure with C4v symmetry, as confirmed by its high-resolution 19F NMR spectrum. It was first synthesized in 1963. Preparation Some of the earliest research on the preparation was classified. It was first prepared by fluorination of chlorine trifluoride at high temperatures and high pressures: : : : : catalyzes this reaction. Certain metal fluorides, , e.g. (potassium tetrafluorochlorate(III)), (rubidium tetrafluorochlorate(III)), (caesium tetrafluorochlorate(III)), react with to produce and the corresponding alkali metal fluoride. Reactions In a highly exothermic reaction, reacts with water to produce chloryl fluoride and hydrogen fluoride: : It is also a strong fluorinating agent. At room temperature it reacts readily with all elements (including otherwise "inert" elem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine Pentafluoride
Bromine pentafluoride, Br F5, is an interhalogen compound and a fluoride of bromine. It is a strong fluorinating agent. BrF5 finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of BrF5 releases O2 for subsequent analysis. It has also been tested as an oxidizer in liquid rocket propellants and is used as a fluorinating agent in the processing of uranium. Preparation BrF5 was first prepared in 1931 by the direct reaction of bromine and fluorine. This reaction is suitable for the preparation of large quantities, and is carried out at temperatures over with an excess of fluorine: :Br2 + 5 F2 → 2 BrF5 For the preparation of smaller amounts, potassium bromide is used: :KBr + 3 F2 → KF + BrF5 This route yields BrF5 almost completely free of trifluorides and other impurities. Reactions BrF5 reacts with water to form bromic acid and hydrofluoric acid: :BrF5 + 3 H2O → HBrO3 + 5 HF It is an extremely effective fluorinating agent, bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon Hexafluoride
Xenon hexafluoride is a noble gas compound with the formula XeF6. It is one of the three binary fluorides of xenon that have been studied experimentally, the other two being XeF2 and XeF4. All of them are exergonic and stable at normal temperatures. XeF6 is the strongest fluorinating agent of the series. It is a colorless solid that readily sublimes into intensely yellow vapors. Preparation Xenon hexafluoride can be prepared by heating of XeF2 at about 300 °C under 6 MPa (60 atmospheres) of fluorine. With as catalyst, however, this reaction can proceed at 120 °C even in xenon-fluorine molar ratios as low as 1:5. Structure The structure of XeF6 required several years to establish in contrast to the cases of and . In the gas phase the compound is monomeric. VSEPR theory predicts that due to the presence of six fluoride ligands and one lone pair of electrons the structure lacks perfect octahedral symmetry, and indeed electron diffraction combined with high-level cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also used to search for hypothetical weakly interacting massive particles and as a propellant for ion thrusters in spacecraft. Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive xe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold(V) Fluoride
Gold(V) fluoride is the inorganic compound with the formula Au2F10. This fluoride compound features gold in its highest known oxidation state. This red solid dissolves in hydrogen fluoride but these solutions decompose, liberating fluorine. The structure of gold(V) fluoride in the solid state is centrosymmetric with hexacoordinated gold and an octahedral molecular geometry, octahedral arrangement of the fluoride centers on each gold center. It is the only known dimeric pentafluoride, although sulfur can form disulfur decafluoride; other pentafluorides are monomeric (Phosphorus pentafluoride, P, Arsenic pentafluoride, As, Antimony pentafluoride, Sb, Chlorine pentafluoride, Cl, Bromine pentafluoride, Br, Iodine pentafluoride, I), tetrameric (Niobium pentafluoride, Nb, Tantalum pentafluoride, Ta, Chromium pentafluoride, Cr, Molybdenum pentafluoride, Mo, Tungsten pentafluoride, W, Technetium pentafluoride, Tc, Rhenium pentafluoride, Re, Ruthenium pentafluoride, Ru, Osmium pentafluoride ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactivity (chemistry), reactive chemical elements, being the second-lowest in the reactivity series. It is solid under standard temperature and pressure, standard conditions. Gold often occurs in free elemental (native state (metallurgy), native state), as gold nugget, nuggets or grains, in rock (geology), rocks, vein (geology), veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
