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Vanadium(III) Fluoride
Vanadium(III) fluoride is the chemical compound with the formula V F3. This yellow-green, refractory solid is obtained in a two-step procedure from V2O3. Similar to other transition-metal fluorides (such as MnF2), it exhibits magnetic ordering at low temperatures (e.g. V2F6.4H2O orders below 12 KS. Nakhal et al., Z. Kristallogr. 228, 347 (2013).). Preparation The first step entails conversion to the hexafluorovanadate(III) salt using ammonium bifluoride The bifluoride ion is an inorganic anion with the chemical formula . The anion is colorless. Salts of bifluoride are commonly encountered in the reactions of fluoride salts with hydrofluoric acid. The commercial production of fluorine involves ...: :V2O3 + 6 (NH4)HF2 → 2 (NH4)3VF6 + 3 H2O In the second step, the hexafluorovanadate is thermally decomposed. :(NH4)3VF6 → 3 NH3 + 3 HF + VF3 The thermal decomposition of ammonium salts is a relatively common method for the preparation of inorganic solids. VF3 can also be p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol for ethyl group, ethyl. Ethanol is a Volatility (chemistry), volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. As a psychoactive depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine. Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the Chemical synthesis, synthesis of orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonal Crystal System
In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crystal system and the rhombohedral lattice system are not equivalent (see section crystal systems below). In particular, there are crystals that have trigonal symmetry but belong to the hexagonal lattice (such as α-quartz). The hexagonal crystal family consists of the 12 point groups such that at least one of their space groups has the hexagonal lattice as underlying lattice, and is the union of the hexagonal crystal system and the trigonal crystal system. There are 52 space groups associated with it, which are exactly those whose Bravais lattice is either hexagonal or rhombohedral. __TOC__ Lattice systems The hexagonal crystal family consists of two lattice systems: hexagonal and rhombohedral. Each lattice system consists of one Bravais lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Symbol
The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure. It was originated by William Burton Pearson and is used extensively in Pearson's handbook of crystallographic data for intermetallic phases. The symbol is made up of two letters followed by a number. For example: * Diamond structure, cF8 * Rutile structure, tP6 Construction The two letters in the Pearson symbol specify the Bravais lattice, and more specifically, the lower-case letter specifies the Crystal system, crystal family, while the upper-case letter the Lattice (group), lattice type. The number at the end of the Pearson symbol gives the number of the atoms in the conventional unit cell (atoms which satisfy 1 > x,y,z \geq 0 for the atom's position (x,y,z) in the unit cell). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(III) Chloride
Vanadium(III) chloride describes the inorganic compound with the formula VCl3 and its hydrates. It forms a purple anhydrous form and a green hexahydrate Cl2(H2O)4l·2H2O. These hygroscopic salts are common precursors to other vanadium(III) complexes and is used as a mild reducing agent. Structure and electronic configuration VCl3 has the common layered BiI3 structure, a motif that features hexagonally closest-packed chloride framework with vanadium ions occupying the octahedral holes. VBr3 and VI3 adopt the same structure, but VF3 features a structure more closely related to ReO3. The V3+cation has a ''d''2 electronic configuration with two unpaired electrons, making the compound paramagnetic.Greenwood, N. N. and Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. p. 990 . VCl3 is a Mott insulator and undergoes an antiferromagnetic transition at low temperatures. Solid hexahydrate, Cl2(H2O)4l·2H2O, has a monoclinic crystal structure an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(III) Oxide
Vanadium(III) oxide is the inorganic compound with the formula V2O3. It is a black solid prepared by reduction of V2O5 with hydrogen or carbon monoxide. It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. V2O3 has the corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium, and chromium. It is a rock (geology), rock-forming mineral. It is a naturally transparency and translucency, transparent material, but ... structure. It is antiferromagnetic with a critical temperature of 160 K, below which there is an abrupt change in conductivity from metallic to insulating.E.M. Page, S.A.Wass (1994),''Vanadium:Inorganic and Coordination chemistry'', Encyclopedia of Inorganic Chemistry, John Wiley & Sons, This also distorts the crystal structure to a monoclinic space group: C2/c. Upon exposure to air it gradually converts into indigo-blue V2O4. In nature it occurs as the rare mineral kare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(III) Nitride
Vanadium nitride, VN, is a chemical compound of vanadium and nitrogen. Vanadium nitride is formed during the nitriding of steel and increases wear resistance. Another phase, V2N, also referred to as vanadium nitride, can be formed along with VN during nitriding. VN has a cubic, rock-salt structure. There is also a low-temperature form, which contains V4 clusters. The low-temperature phase results from a dynamic instability, when the energy of vibrational modes in the high-temperature NaCl-structure phase, are reduced below zero. It is a strong-coupled superconductor. Nanocrystalline vanadium nitride has been claimed to have potential for use in supercapacitors alt=Supercapacitor, upright=1.5, Schematic illustration of a supercapacitor upright=1.5, A diagram that shows a hierarchical classification of supercapacitors and capacitors of related types A supercapacitor (SC), also called an ultracapacitor, .... The properties of vanadium nitride depend sensitively on the stoichiom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(IV) Fluoride
Vanadium(IV) fluoride ( V F4) is an inorganic compound of vanadium and fluorine. It is paramagnetic yellow-brown solid that is very hygroscopic. Unlike the corresponding vanadium tetrachloride, the tetrafluoride is not volatile because it adopts a polymeric structure. It decomposes before melting. Preparation and reactions VF4 can be prepared by treating VCl4 with HF: :VCl4 + 4 HF → VF4 + 4 HCl It was first prepared in this way. It decomposes at 325 °C, undergoing disproportionation to the tri- and pentafluorides: :2 VF4 → VF3 + VF5 Structure The structure of VF4 is related to that of SnF4. Each vanadium centre is octahedral, surrounded by six fluoride ligands. Four of the fluoride centers bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ... to adjacent vanadiu ... [...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 or new bonds formed or both. 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, usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium
Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation (chemistry), passivation) somewhat stabilizes the free metal against further oxidation. Spain, Spanish-Mexico, Mexican scientist Andrés Manuel del Río discovered compounds of vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead". Though he initially presumed its qualities were due to the presence of a new element, he was later erroneously convinced by French chemist Hippolyte Victor Collet-Descotils that the element was just chromium. Then in 1830, Nils Gabriel Sefström generated chlorides of vanadium, thus proving there was a new element, and named it "vanadium" after the Scandinavian goddess of beauty and fertility, Vanadís (Freyja). The name was based on the wide range of colors fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extremely Reactivity (chemistry), reactive as it reacts with all other Periodic table, elements except for the light Noble gas, noble gases. It is highly toxicity, toxic. Among the elements, fluorine ranks Abundance of the chemical elements, 24th in cosmic abundance and 13th in crustal 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 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 He ... [...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'' originated as an acronym for light amplification by stimulated emission of radi ...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] |
Ammonium
Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleus) to ammonia (). Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations (), where one or more hydrogen atoms are replaced by Organic compound, organic or other groups (indicated by R). Not only is ammonium a source of nitrogen and a key metabolite for many living organisms, but it is an integral part of the global nitrogen cycle. As such, human impact in recent years could have an effect on the biological communities that depend on it. Acid–base properties The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted–Lowry acid–base theory, Brønsted acids (proton donors): : The ammonium ion is mildly acidic, reacting with Brønsted bases to return ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
