|
Difluoride
Difluorides are chemical compounds with two fluorine atoms per molecule (or per formula unit). Metal difluorides are all ionic. Despite being highly ionic, the alkali earth metal difluorides generally have extremely high lattice stability and are thus insoluble in water. One exception is beryllium difluoride. In addition, many transition metal difluorides are water-soluble. Calcium difluoride is a notable compound. In the form of the mineral fluorite it is the major source of commercial fluorine. It also has an eponymic crystal structure, which is an end member of the spectrum starting from bixbyite and progressing through pyrochlore. List of the difluorides Examples of the difluorides include: Alkaline earth metal difluorides The alkaline earth metals all exhibit the oxidation state +2, and form difluorides. The difluoride of radium is however not well established due to the element's high radioactivity. * Beryllium difluoride * Magnesium fluoride * Calcium fluorid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reactive, as it reacts with all other elements except for the light inert gases. Among the elements, fluorine ranks 24th in universal abundance and 13th in terrestrial abundance. Fluorite, the primary mineral source of fluorine which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb meaning 'flow' gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its compounds, and several early experimenters died or sustained injuries from their attempts. Only in 1886 did French chemist Henri Moissan isolate elemental fluorine using low-temperature electrolysis, a process still employed for modern pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strontium Difluoride
Strontium fluoride, SrF2, also called strontium difluoride and strontium(II) fluoride, is a fluoride of strontium. It is a brittle white crystalline solid. In nature, it appears as the very rare mineral strontiofluorite. Preparation Strontium fluoride is prepared by the action of hydrofluoric acid on strontium carbonate. Structure The solid adopts the fluorite structure. In the vapour phase the SrF2 molecule is non-linear with an F−Sr−F angle of approximately 120°. This is an exception to VSEPR theory which would predict a linear structure. Ab initio calculations have been cited to propose that contributions from d orbitals in the shell below the valence shell are responsible. Another proposal is that polarization of the electron core of the strontium atom creates an approximately tetrahedral distribution of charge that interacts with the Sr−F bonds.Core Distortions and Geometries of the Difluorides and Dihydrides of Ca, Sr, and Ba Bytheway I, Gillespie RJ, Tang TH, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt Difluoride
Cobalt(II) fluoride is a chemical compound with the formula (CoF2). It is a pink crystalline solid compound which is antiferromagnetic at low temperatures (TN=37.7 K) The formula is given for both the red tetragonal crystal, (CoF2), and the tetrahydrate red orthogonal crystal, (CoF2·4H2O). CoF2 is used in oxygen-sensitive fields, namely metal production. In low concentrations, it has public health uses. CoF2 is sparingly soluble in water. The compound can be dissolved in warm mineral acid, and will decompose in boiling water. Yet the hydrate is water-soluble, especially the di-hydrate CoF2·2H2 O and tri-hydrate CoF2·3H2O forms of the compound. The hydrate will also decompose with heat. Like some other metal difluorides, CoF2 crystallizes in the rutile structure, which features octahedral Co centers and planar fluorides. Preparation Cobalt(II) fluoride can be prepared from anhydrous cobalt(II) chloride or cobalt(II) oxide in a stream of hydrogen fluoride: :CoCl2 + 2HF → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(II) Fluoride
Chromium(II) fluoride is an inorganic compound with the formula CrF2. It exists as a blue-green iridescent solid. Chromium(II) fluoride is sparingly soluble in water, almost insoluble in alcohol, and is soluble in boiling hydrochloric acid, but is not attacked by hot distilled sulfuric acid or nitric acid. Like other chromous compounds, chromium(II) fluoride is oxidized to chromium(III) oxide in air. Preparation and structure The compound is prepared by passing anhydrous hydrogen fluoride over anhydrous chromium(II) chloride. The reaction will proceed at room temperature but is typically heated to 100-200 °C to ensure completion: :CrCl2 + 2 HF → CrF2 + 2 HCl Like many difluorides, CrF2 adopts a structure like rutile with octahedral molecular geometry about Cr(II) and trigonal geometry at F−. Two of the six Cr–F bonds are long at 2.43 Å, and four are short near 2.00 Å. This distortion is a consequence of the Jahn–Teller effect that arises from the d4 el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium Difluoride
Beryllium fluoride is the inorganic compound with the formula Be F2. This white solid is the principal precursor for the manufacture of beryllium metal. Its structure resembles that of quartz, but BeF2 is highly soluble in water. Properties Beryllium fluoride has distinctive optical properties. In the form of fluoroberyllate glass it has the lowest refractive index for a solid at room temperature of 1.275. Its dispersive power is the lowest for a solid at 0.0093, and the nonlinear coefficient is also the lowest at 2 × 10−14. Structure and bonding The structure of solid BeF2 resembles that of cristobalite. Be2+ centers are four coordinate and tetrahedral and the fluoride centers are two-coordinate. The Be-F bond lengths are about 1.54 Å. Analogous to SiO2, BeF2 can also adopt a number of related structures. An analogy also exists between BeF2 and AlF3: both adopt extended structures at mild temperature. Gas and liquid BeF2 Gaseous beryllium fluoride adopts a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel Difluoride
Nickel(II) fluoride is the chemical compound with the formula NiF2. It is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air. Nickel(II) fluoride is also produced when nickel metal is exposed to fluorine. In fact, NiF2 comprises the passivating surface that forms on nickel alloys (e.g. monel) in the presence of hydrogen fluoride or elemental fluorine. For this reason, nickel and its alloys are suitable materials for storage and transport these fluorine and related fluorinating agents. NiF2 is also used as a catalyst for the synthesis of chlorine pentafluoride. Preparation and structure NiF2 is prepared by treatment of anhydrous nickel(II) chloride with fluorine at 350 °C: :NiCl2 + F2 → NiF2 + Cl2 The corresponding reaction of cobalt(II) chloride results in oxidation of the cobalt, whereas nickel remains in the +2 oxidation state after fluorination because its +3 oxidation sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese(II) Fluoride
Manganese(II) fluoride is the chemical compound composed of manganese and fluoride with the formula MnF2. It is a light pink solid, the light pink color being characteristic for manganese(II) compounds. It is made by treating manganese and diverse compounds of manganese(II) in hydrofluoric acid. Like some other metal difluorides, MnF2 crystallizes in the rutile structure, which features octahedral Mn centers. Uses MnF2 is used in the manufacture of special kinds of glass and laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...s. It is a canonical example of uniaxial antiferromagnet (with Neel temperature of 68 K) which has been experimentally studied since early on. References Manganese(II) compounds Fluorides Metal halides {{inorganic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(II) Fluoride
Copper(II) fluoride is an inorganic compound with the chemical formula CuF2. The anhydrous form is a white, ionic, crystalline, hygroscopic solid with a distorted rutile-type crystal structure, similar to other fluorides of chemical formulae MF2 (where M is a metal). The dihydrate, , is blue in colour. Structure Copper(II) fluoride has a monoclinic crystal structure and cannot achieve a higher-symmetry structure. It forms rectangular prisms with a parallelogram base. Each copper ion has four neighbouring fluoride ions at 1.93 Å separation and two further away at 2.27 Å. This distorted octahedral +2 coordination is a consequence of the Jahn–Teller effect in d9 copper(II), and leads to a distorted rutile structure similar to that of chromium(II) fluoride, , which is a d4 compound. Uses Copper (II) fluoride can be used to make fluorinated aromatic hydrocarbons by reacting with aromatic hydrocarbons in an oxygen-containing atmosphere at temperatures above 450 °C (84 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium Difluoride
Cadmium fluoride (CdF2) is a mostly water-insoluble source of cadmium used in oxygen-sensitive applications, such as the production of metallic alloys. In extremely low concentrations (ppm), this and other fluoride compounds are used in limited medical treatment protocols. Fluoride compounds also have significant uses in synthetic organic chemistry. The standard enthalpy has been found to be -167.39 kcal. mole−1 and the Gibbs energy of formation has been found to be -155.4 kcal. mole−1, and the heat of sublimation was determined to be 76 kcal. mole−1. Preparation Cadmium fluoride is prepared by the reaction of gaseous fluorine or hydrogen fluoride with cadmium metal or its salts, such as the chloride, oxide, or sulfate. It may also be obtained by dissolving cadmium carbonate in 40% hydrofluoric acid solution, evaporating the solution and drying in a vacuum at 150 °C. Another method of preparing it is to mix cadmium chloride and ammonium fluoride solutions, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europium Difluoride
Europium(II) fluoride is an inorganic compound with a chemical formula EuF2. It was first synthesized in 1937.Zhao Yongzhi, Ma Ying, Hou Shaochun, Zhang Wenjuan, Wang Jingjing, Ding Yanrong, Hao Yifan氟化亚铕研究现状(''lit''. Research Progress of Europium(II) Fluoride). ''Chinese Rare Earths'', 2017. 38 (5): 134-140. (in Chinese) Production Europium(II) fluoride can be produced by reducing europium(III) fluoride with metallic europium or hydrogen gasGeorg Brauer: ''Handbuch der Präparativen Anorganischen Chemie''. 3., umgearb. Auflage. Band I. Enke, Stuttgart 1975, , S. 255. :\mathrm :\mathrm Properties Europium(II) fluoride is a bright yellowish solid with a fluorite structure. EuF2 can be used to dope a trivalent rare-earth fluoride, such as LaF3, to create a vacancy-filled structure with increased conductivity over a pure crystal. Such a crystal can be used as a fluoride-specific semipermeable membrane Semipermeable membrane is a type of biological or synthet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palladium Difluoride
Palladium(II) fluoride, also known as palladium difluoride, is the chemical compound of palladium and fluorine with the formula PdF2. Synthesis PdF2 is prepared by refluxing palladium(II,IV) fluoride, PdII dIVF6 with selenium tetrafluoride, SeF4. :Pd dF6+ SeF4 → 2PdF2 + SeF6 Structure and paramagnetism Like its lighter congener nickel(II) fluoride, PdF2 adopts a rutile-type crystal structure, containing octahedrally coordinated palladium, which has the electronic configuration t e. This configuration causes PdF2 to be paramagnetic due to two unpaired electrons, one in each eg-symmetry orbital of palladium. Applications Palladium fluoride is an insoluble powder used in infrared optical sensors, and in situations where reactivity to oxygen makes palladium oxide Palladium(II) oxide is the inorganic compound of formula Pd O. It is the only well characterised oxide of palladium. It is prepared by treating the metal with oxygen. Above about 900 °C, the oxide revert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium Difluoride
Beryllium fluoride is the inorganic compound with the formula Be F2. This white solid is the principal precursor for the manufacture of beryllium metal. Its structure resembles that of quartz, but BeF2 is highly soluble in water. Properties Beryllium fluoride has distinctive optical properties. In the form of fluoroberyllate glass it has the lowest refractive index for a solid at room temperature of 1.275. Its dispersive power is the lowest for a solid at 0.0093, and the nonlinear coefficient is also the lowest at 2 × 10−14. Structure and bonding The structure of solid BeF2 resembles that of cristobalite. Be2+ centers are four coordinate and tetrahedral and the fluoride centers are two-coordinate. The Be-F bond lengths are about 1.54 Å. Analogous to SiO2, BeF2 can also adopt a number of related structures. An analogy also exists between BeF2 and AlF3: both adopt extended structures at mild temperature. Gas and liquid BeF2 Gaseous beryllium fluoride adopts a linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_-_cropped.png "Click for more on -> Difluoride")
