|
Cobalt(III) Oxide
Cobalt(III) oxide is the inorganic compound with the formula of Co2O3. Although only two oxides of cobalt are well characterized, CoO and Co3O4, procedures claiming to give Co2O3 have been described. Thus treatment of Co(II) salts such as cobalt(II) sulfate with an aqueous solution of sodium hypochlorite (also known as bleach) gives a black solid: :2CoSO4 + 4NaOH + NaOCl → Co2O3 + 2Na2SO4 + NaCl Some formulations of the catalyst hopcalite contain "Co2O3". Some studies have been unable to synthesize the compound, and report that it is theoretically unstable. It is soluble in cold diluted sulfuric acid and produces Co2 O4sub>3, which is blue in aqueous solution. : Co2O3 + 3H2SO4 → Co2 O4sub>3 + 3H2O Colbalt(III) ion is a strong oxidizer in acidic solution, its standard electrode potential is +1.84V in this situation. See also *Cobalt Oxide Nanoparticles In materials and electric battery research, cobalt oxide nanoparticles usually refers to particles of cobalt( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corundum
Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present. A rare type of sapphire, padparadscha sapphire, is pink-orange. The name "corundum" is derived from the Tamil- Dravidian word ''kurundam'' (ruby-sapphire) (appearing in Sanskrit as ''kuruvinda''). Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals. It is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood. Emery, a variety of corundum with no value a ... [...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, and was originated by W. B. Pearson. The symbol is made up of two letters followed by a number. For example: * Diamond structure, ''cF''8 * Rutile structure, ''tP''6 The two (italicised) letters specify the Bravais lattice. The lower-case letter specifies the crystal family, and the upper-case letter the centering type. The number at the end of the Pearson symbol gives the number of the atoms in the conventional unit cell.Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005 IR-3.4.4, pp. 49–51; IR-11.5, pp. 241–242. |
Inorganic Compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt(II) Oxide
Cobalt(II) oxide is an inorganic compound that has been described as an olive-green or gray solid. It is used extensively in the ceramics industry as an additive to create blue colored glazes and enamels as well as in the chemical industry for producing cobalt(II) salts. A related material is cobalt(II,III) oxide, a black solid with the formula Co3O4. Structure and properties CoO crystals adopt the periclase (rock salt) structure with a lattice constant of 4.2615 Å. It is antiferromagnetic below 16 °C. Preparation Cobalt(II) oxide is prepared by oxidation of cobalt powder with air or by thermal decomposition of cobalt(II) nitrate or the carbonate. Cobalt(II,III) oxide decomposes to cobalt(II) oxide at 950 °C: :2 Co3O4 → 6 CoO + O2 It may also be prepared by precipitating the hydroxide, followed by thermal dehydration: : CoX2 + 2 KOH → Co(OH)2 + 2 KX : Co(OH)2 → CoO + H2O Reactions As can be expected, cobalt(II) oxide reacts with mineral acids to form the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt(II,III) Oxide
Cobalt(II,III) oxide is an inorganic compound with the formula Co3O4. It is one of two well characterized cobalt oxides. It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as CoIICoIII2O4 and sometimes as CoO•Co2O3. Structure Co3O4 adopts the normal spinel structure, with Co2+ ions in tetrahedral interstices and Co3+ ions in the octahedral interstices of the cubic close-packed lattice of oxide anions. Synthesis Cobalt(II) oxide, CoO, converts to Co3O4 upon heating at around 600–700 °C in air. Above 900 °C, CoO is stable. These reaction are described by the following equilibrium: :2 Co3O4 6 CoO + O2 Applications Cobalt(II,III) oxide is used as a blue coloring agent for pottery enamel and glass, as an alternative to cobalt(II) oxide.Frank Hamer, Janet Hamer (2004)''The Potter's Dictionary of Materials and Techniques'' University of Pennsylvania Press; 437 pp. Cobalt(II,III) oxide is used as an elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt(II) Sulfate
Cobalt(II) sulfate is any of the inorganic compounds with the formula CoSO4(H2O)x. Usually cobalt sulfate refers to the hexa- or heptahydrates CoSO4.6H2O or CoSO4.7H2O, respectively. The heptahydrate is a red solid that is soluble in water and methanol. Since cobalt(II) has an odd number of electrons, its salts are paramagnetic. Preparation, and structure It forms by the reaction of metallic cobalt, its oxide, hydroxide, or carbonate with aqueous sulfuric acid: :Co + H2SO4 + 7 H2O → CoSO4(H2O)7 + H2 :CoO + H2SO4 + 6 H2O → CoSO4(H2O)7 The heptahydrate is only stable at humidity >70% at room temperature, otherwise it converts to the hexahydrate. The hexahydrate converts to the monohydrate and the anhydrous forms at 100 and 250 °C, respectively. :CoSO4(H2O)7 → CoSO4(H2O)6 + H2O :CoSO4(H2O)6 → CoSO4(H2O) + 5H2O :CoSO4(H2O) → CoSO4 + H2O The hexahydrate is a metal aquo complex consisting of octahedral o(H2O)6sup>2+ ions associated with sulfate a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may also be viewed as the sodium salt (chemistry), salt of hypochlorous acid. The anhydrous Chemical compound, compound is unstable and may decompose explosively. It can be crystallized as a hydrate, pentahydrate ·5, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated. Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as liquid bleach, which is a household chemical widely used (since the 18th century) as a disinfectant or a bleaching agent. In solution, the compound is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Sodium hypochlorite is the oldest and still most important chlorine-releasing compounds, chl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hopcalite
Hopcalite is the trade name for a number of mixtures that mainly consist of oxides of copper and manganese, which are used as catalysts for the conversion of carbon monoxide to carbon dioxide when exposed to the oxygen in the air at room temperature. The name "hopcalite" is derived from Johns Hopkins University - "Hop" and the University of California - "Cal", where basic research into carbon monoxide was carried out during the First World War and these catalysts were discovered in 1918. A variety of compositions are known, such as "hopcalite II" that is approximately 60% manganese dioxide and 40% copper oxide (the MnO2 : CuO molar ratio is 1.375) and "hopcalite I" that is a mixture of 50% MnO, 30% CuO, 15% Co2O3, and 5% Ag2O. Hopcalite has the properties of a porous mass and resembles activated carbon in its appearance. Preparation While typically hopcalite catalysts are prepared by calcining intimate mixtures of oxides and carbonates, various techniques have been employed f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidizer
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide and the halogens. In one sense, an oxidizing agent is a chemical species that undergoes a chemical reaction in which it gains one or more electrons. In that sense, it is one component in an oxidation–reduction (redox) reaction. In the second sense, an oxidizing agent is a chemical species that transfers electronegative atoms, usually oxygen, to a substrate. Combust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Electrode Potential
In electrochemistry, standard electrode potential E^\ominus, or E^\ominus_, is a measure of the reducing power of any element or compound. The IUPAC "Gold Book" defines it as: ''"the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode"''. Background The basis for an electrochemical cell, such as the galvanic cell, is always a redox reaction which can be broken down into two half-reactions: oxidation at anode (loss of electron) and reduction at cathode (gain of electron). Electricity is produced due to the difference of electric potential between the individual potentials of the two metal electrodes with respect to the electrolyte. Although the overall potential of a cell can be measured, there is no simple way to accurately measure the electrode/electrolyte potentials in isolation. The electric potential also varies with temperature, concentration and pressure. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt Oxide Nanoparticles
In materials and electric battery research, cobalt oxide nanoparticles usually refers to particles of cobalt(II,III) oxide of nanometer size, with various shapes and crystal structures. Cobalt oxide nanoparticles have potential applications in lithium-ion batteries and electronic gas sensors. Applications Lithium-ion Battery The cathodes of lithium-ion batteries are often made of lithiated oxides of cobalt, nickel, or manganese, that can readily and reversibly incorporate lithium ions in their molecular structure. Cobalt oxide nanomaterials, such as nanotubes, offer high surface-to-volume ratio and short path lengths for lithium cation transport, leading to fast charging capabilities. However, capacity, coulombic efficiency, and cycle life may suffer due to excessive formation of SEI. The nanowires may incorporate other substances, for example, diphenylalanine. Cobalt oxide particles may be anchored on substrates such as graphene to improve the dimensional stability of the an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
-oxide-xtal-2006-Co(II)-coord-CM-3D-balls.png "Click for more on -> Cobalt(II,III) Oxide")
