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Friedel's Salt
Friedel's salt is an anion exchanger mineral belonging to the family of the layered double hydroxides (LDHs). It has affinity for anions as chloride and iodide and is capable of retaining them to a certain extent in its crystallographical structure. Composition Friedel's salt is a layered double hydroxide (LDH) of general formula: : or more explicitly for a positively-charged LDH mineral: : or by directly incorporating water molecules into the Ca,Al hydroxide layer: : where chloride and hydroxide anions occupy the interlayer to compensate the excess of positive charges. In the cement chemist notation (CCN), considering that : and doubling all the stoichiometry, it could also be written in CCN as follows: : A simplified chemical composition with only Cl– in the interlayer, and without OH–, as: : can be also written in cement chemist notation as: : Friedel's salt is formed in cements initially rich in tri-calcium aluminate (C3A). Free-chloride ions directl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anion Exchanger
Ion exchange is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for softening or making water demineralised, the purification of chemicals and separation of substances. Ion exchange usually describes a process of purification of aqueous solutions using solid polymeric ion-exchange resin. More precisely, the term encompasses a large variety of processes where ions are exchanged between two electrolytes. Aside from its use to purify drinking water, the technique is widely applied for purification and separation of a variety of industrially and medicinally important chemicals. Although the term usually refers to applications of synthetic (man-made) resins, it can include many other materials such as soil. Typical ion exchangers are ion-exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus. Ion exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Chloride
Magnesium chloride is the family of inorganic compounds with the formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available. Production Magnesium chloride can be extracted from brine or sea water. In North America, it is produced primarily from Great Salt Lake brine. In the Jordan Valley, it is obtained from the Dead Sea. The mineral bischofite () is extracted (by solution mining) out of ancient seabeds, for example, the Zechstein seabed in northwest Europe. Some deposits result from high content of magnesium chloride in the primordial ocean. Some magnesium chloride is made from evaporation of seawater. In the Dow process, magnesium chloride is re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrates
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understood. Chemical nature Inorganic chemistry Hydrates are inorganic salts "containing water molecules combined in a definite ratio as an integral part of the crystal" that are either bound to a metal center or that have crystallized with the metal complex. Such hydrates are also said to contain ''water of crystallization'' or ''water of hydration''. If the water is heavy water in which the constituent hydrogen is the isotope deuterium, then the term ''deuterate'' may be used in place of ''hydrate''. A colorful example is cobalt(II) chloride, which turns from blue to red upon hydration, and can therefore be used as a water indicator. The notation "''hydrated compound''⋅''n''", where ''n'' is the number of water molecules per formula un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallography
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] |
Calcium Compounds
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminates
In chemistry, an aluminate is a compound containing an oxyanion of aluminium, such as sodium aluminate. In the naming of inorganic compounds, it is a suffix that indicates a polyatomic anion with a central aluminum atom. Aluminate oxyanions Aluminium oxide (alumina) is amphoteric: it dissolves in both bases and acids. When dissolved in bases it forms hydroxyaluminate ions in the same way as aluminium hydroxide or aluminium salts. The hydroxyaluminate or hydrated aluminate can be precipitated and then calcined to produce anhydrous aluminates. Aluminates are often formulated as a combination of basic oxide and aluminium oxide, for example the formula of anhydrous sodium aluminate NaAlO2 would be shown as Na2O·Al2O3. A number of aluminate oxyanions are known: * The simplest is the approximately tetrahedral found in the compound Na5AlO4, * framework ions in anhydrous sodium aluminate NaAlO2 and monocalcium aluminate, CaAl2O4 made up of corner-sharing tetrahedra. * A ring anion, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacques Friedel
Jacques Friedel ForMemRS (; 11 February 1921 – 27 August 2014) was a French physicist and material scientist. Education Friedel attended the Cours Hattemer, a private school. He studied at the École Polytechnique from 1944 to 1946, and the École nationale supérieure des mines de Paris from 1946 to 1948. He graduated from the University of Paris with a Licence ès sciences degree in 1948, then studied at the Metallurgy Laboratory of the School of Mines with Charles Crussard. He graduated from the University of Bristol with a PhD in 1952, where he studied with Nevill Francis Mott, and a Doctorat d'Etat in Paris in 1954. Career He was assistant professor at Paris-Sorbonne University in 1956, then full professor of Solid State Physics (from 1959 to 1989) at the University of Paris-Sud where he co-founded the Laboratory of Solid State Physics. He authored more than 200 journal articles. He was the president of the Société française de physique, the European Physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedel Family
Four French scientists with the same Friedel family name are in direct lineage, Charles, Georges, Edmond and Jacques: * Charles Friedel (1832–1899), French chemist known for the Friedel-Crafts reaction * Georges Friedel (1865–1933), French crystallographer and mineralogist; son of Charles * Edmond Friedel (1895–1972), French Polytechnician and mining engineer, founder of BRGM, the French geological survey; son of Georges * Jacques Friedel, (1921–2014), French physicist; son of Edmond, see the French site for Jacques Friedel Related items * Friedel Crafts Alkylation, a type of organic reaction developed by Charles Friedel and James Crafts in 1877. * Friedel's law Friedel's law, named after Georges Friedel, is a property of Fourier transforms of real functions. Given a real function f(x), its Fourier transform :F(k)=\int^_f(x)e^dx has the following properties. *F(k)=F^*(-k) \, where F^* is the complex co ..., named after Georges Friedel, the crystallographer, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Layered Double Hydroxides
Layered double hydroxides (LDH) are a class of ionic solids characterized by a layered structure with the generic layer sequence cB Z AcBsub>''n'', where c represents layers of metal cations, A and B are layers of hydroxide () anions, and Z are layers of other anions and neutral molecules (such as water). Lateral offsets between the layers may result in longer repeating periods. The intercalated anions (Z) are weakly bound, often exchangeable; their intercalation properties have scientific interest and industrial applications. LDHs occur in nature as minerals, as byproducts of metabolism of certain bacteria, and also unintentionally in man-made contexts, such as the products of corrosion of metal objects. Structure and formulas LDHs can be seen as derived from hydroxides of divalent cations (d) with the brucite (Mg(OH)2) layer structure dB AdBsub>''n'', by cation (c) replacement (Mg2+ → Al3+), or by cation oxidation (Fe2+ → Fe3+ in the case of green rust, Fe(OH)2), in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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