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Vanadium Oxide
Vanadium oxide may refer to: * Vanadium(II) oxide (vanadium monoxide), VO * Vanadium(III) oxide (vanadium sesquioxide ''or'' trioxide), V2O3 * Vanadium(IV) oxide (vanadium dioxide), VO2 * Vanadium(V) oxide (vanadium pentoxide), V2O5 * Vanadium(VI) oxide (vanadium hexoxide), a green oxide produced by a combination of hydrogen peroxide and vanadium metal In addition to these principal oxides of vanadium, various other distinct phases exist: * Phases with the general formula VnO2n+1 exist between V2O5 and VO2. Examples of these phases include V3O7, V4O9 and V6O13. * Phases with the general formula VnO2n−1 exist between VO2 and V2O3. Called Magnéli phases foArne Magnéli they are examples of crystallographic shear compounds based on the rutile structure. Examples of Magnéli phases include V4O7, V5O9, V6O11, V7O13 and V8O15. * V3O5 appears as the mineral oxyvanite. Many vanadium-oxygen phases are non-stoichiometric In chemistry, non-stoichiometric compounds are chemical comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(II) Oxide
Vanadium(II) oxide is the inorganic compound with the idealized formula VO. It is one of the several binary vanadium oxides. It adopts a distorted NaCl structure and contains weak V−V metal to metal bonds. VO is a semiconductor owing to delocalisation of electrons in the t2g orbitals. VO is a non-stoichiometric compound In chemistry, non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); m ..., its composition varying from VO0.8 to VO1.3. Diatomic VO is one of the molecules found in the spectrum of relatively cool M-type stars. References Vanadium(II) compounds Non-stoichiometric compounds Transition metal oxides Rock salt crystal structure {{inorganic-compound-stub ... [...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 structure. It is antiferromagnetic with a critical temperature of 160 K. E.M. Page, S.A.Wass (1994),''Vanadium:Inorganic and Coordination chemistry'', Encyclopedia of Inorganic Chemistry, John Wiley & Sons, At this temperature there is an abrupt change in conductivity from metallic to insulating. 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 karelianite Karelianite is an rare mineral, a natural form of vanadium(III) oxide, V2O3. In terms of chemistry it is vanadium-analogue of hematite, corundum, eskolaite, tistarite, bixbyite, avicennite Avicennite ( thallium(III) oxide) is an ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(IV) Oxide
Vanadium(IV) oxide or vanadium dioxide is an inorganic compound with the formula VO2. It is a dark blue solid. Vanadium(IV) dioxide is amphoteric, dissolving in non-oxidising acids to give the blue vanadyl ion, Osup>2+ and in alkali to give the brown 4O9sup>2− ion, or at high pH O4sup>4−. VO2 has a phase transition very close to room temperature (~). Electrical resistivity, opacity, etc, can change up several orders. Owing to these properties, it has been used in surface coating, sensors, and imaging. Potential applications include use in memory devices, phase-change switches, passive radiative cooling applications, such as smart windows and roofs, that cool or warm depending on temperature, aerospace communication systems and neuromorphic computing. Properties Structure At temperatures below Tc = , has a monoclinic (space group P21/c) crystal structure. Above Tc, the structure is tetragonal, like rutile . In the monoclinic phase, the V4+ ions form pairs along the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(V) Oxide
Vanadium(V) oxide (''vanadia'') is the inorganic compound with the formula V2 O5. Commonly known as vanadium pentoxide, it is a brown/yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of its high oxidation state, it is both an amphoteric oxide and an oxidizing agent. From the industrial perspective, it is the most important compound of vanadium, being the principal precursor to alloys of vanadium and is a widely used industrial catalyst. The mineral form of this compound, shcherbinaite, is extremely rare, almost always found among fumaroles. A mineral trihydrate, V2O5·3H2O, is also known under the name of navajoite. Chemical properties Reduction to lower oxides Upon heating a mixture of vanadium(V) oxide and vanadium(III) oxide, comproportionation occurs to give vanadium(IV) oxide, as a deep-blue solid: :V2O5 + V2O3 → 4 VO2 The reduction can also be effected by oxalic acid, carbon monoxide, and sulfur dioxide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanadium(VI) Oxide
Vanadium is a chemical element with the 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) somewhat stabilizes the free metal against further oxidation. Spanish scientist Andrés Manuel del Río discovered compounds of vanadium in 1801 in Mexico 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 found in vanadium compounds. Del Rio's lead mineral was ult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallographic Shear
Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The word "crystallography" is derived from the Greek word κρύσταλλος (''krystallos'') "clear ice, rock-crystal", with its meaning extending to all solids with some degree of transparency, and γράφειν (''graphein'') "to write". In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming that 2014 would be the International Year of Crystallography. denote a direction vector (in real space). * Coordinates in ''angle brackets'' or ''chevrons'' such as <100> denote a ''family'' of directions which are related by symmetry operations. In the cubic crystal system for example, would mean 00 10 01/nowiki> or the negative of any of those directions. * Miller indices in ''parentheses'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer Polymorphism (materials science), polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive index, refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion (optics), dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially Polarization (waves), polarization optics, for longer light, visible and infrared, infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner. Occurrence Rutile is a common accessory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Structure
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns that repeat along the principal directions of Three-dimensional space (mathematics), three-dimensional space in matter. The smallest group of particles in the material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive Translation (geometry), translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice. The lengths of the principal axes, or edges, of the unit cell and the angles between them are the lattice constants, also called ''lattice parameters'' or ''cell parameters''. The symmetry properties of the crystal are described by the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
