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Gadolinium Diiodide
Gadolinium diiodide is an inorganic compound, with the chemical formula of GdI2. It is an electride, with the ionic formula of Gd3+(I−)2e−, and therefore not a true gadolinium(II) compound. It is ferromagnetic at 276 K with a saturation magnetization of 7.3 B; it exhibits a large negative magnetoresistance Magnetoresistance is the tendency of a material (often ferromagnetic) to change the value of its electrical resistance in an externally-applied magnetic field. There are a variety of effects that can be called magnetoresistance. Some occur in bulk ... (~70%) at 7 T near room temperature. It can be obtained by reacting gadolinium and gadolinium(III) iodide at a high temperature: : Gd + 2 GdI3 → 3 GdI2 It can react with hydrogen at high temperature (800 °C) to obtain gadolinium hydrogen iodide (GdI2H0.97). References {{Lanthanide halides Gadolinium compounds Iodides Electrides Ferromagnetic materials Lanthanide halides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Chemical Formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ''plus'' (+) and ''minus'' (−) signs. These are limited to a single typographic line of symbols, which may include Subscript and superscript, subscripts and superscripts. A chemical formula is not a chemical nomenclature, chemical name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are generally more limited in power than chemical names and structural formulae. The simplest types of chemical formulae are called ''empirical formulae'', which use letters and numbers ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electride
An electride is an ionic compound in which an electron is the anion. Solutions of alkali metals in ammonia are electride salts. In the case of sodium, these blue solutions consist of a(NH3)6sup>+ and solvated electrons: :Na + 6 NH3 → a(NH3)6sup>+ + e− The cation a(NH3)6sup>+ is an octahedral coordination complex. Solid salts Addition of a complexant like crown ether or -cryptand.html" ;"title="''2.2.2/nowiki>-cryptand">''2.2.2/nowiki>-cryptand to a solution of a(NH3)6sup>+e− affords a (crown ether)sup>+e− or a(2,2,2-crypt)sup>+e−. Evaporation of these solutions yields a blue-black paramagnetic solid with the formula a(2,2,2-crypt)sup>+e−. Most solid electride salts decompose above 240 K, although a24Al28O64sup>4+(e−)4 is stable at room temperature. In these salts, the electron is delocalized between the cations. Electrides are paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferromagnetic
Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials are the familiar metals noticeably attracted to a magnet, a consequence of their large magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an ''external'' magnetic field, and it is this temporarily induced magnetization inside a steel plate, for instance, which accounts for its attraction to the permanent magnet. Whether or not that steel plate acquires a permanent magnetization itself, depends not only on the strength of the applied field, but on the so-called coercivity of that material, which varies greatly among ferromagnetic materials. In physics, several different types of material magnetism are distinguished. Ferromagnetism (along with the similar effect ferrimagneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturation Magnetization
Seen in some magnetic materials, saturation is the state reached when an increase in applied external magnetic field ''H'' cannot increase the magnetization of the material further, so the total magnetic flux density ''B'' more or less levels off. (Though, magnetization continues to increase very slowly with the field due to paramagnetism.) Saturation is a characteristic of ferromagnetic and ferrimagnetic materials, such as iron, nickel, cobalt and their alloys. Different ferromagnetic materials have different saturation levels. Description Saturation is most clearly seen in the ''magnetization curve'' (also called ''BH'' curve or hysteresis curve) of a substance, as a bending to the right of the curve (see graph at right). As the ''H'' field increases, the ''B'' field approaches a maximum value asymptotically, the saturation level for the substance. Technically, above saturation, the ''B'' field continues increasing, but at the paramagnetic rate, which is several orders of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetoresistance
Magnetoresistance is the tendency of a material (often ferromagnetic) to change the value of its electrical resistance in an externally-applied magnetic field. There are a variety of effects that can be called magnetoresistance. Some occur in bulk non-magnetic metals and semiconductors, such as geometrical magnetoresistance, Shubnikov–de Haas oscillations, or the common positive magnetoresistance in metals. Other effects occur in magnetic metals, such as negative magnetoresistance in ferromagnets or anisotropic magnetoresistance (AMR). Finally, in multicomponent or multilayer systems (e.g. magnetic tunnel junctions), giant magnetoresistance (GMR), tunnel magnetoresistance (TMR), colossal magnetoresistance (CMR), and extraordinary magnetoresistance (EMR) can be observed. The first magnetoresistive effect was discovered in 1856 by William Thomson, better known as Lord Kelvin, but he was unable to lower the electrical resistance of anything by more than 5%. Today, systems includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gadolinium
Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen or moisture slowly to form a black coating. Gadolinium below its Curie point of is ferromagnetic, with an attraction to a magnetic field higher than that of nickel. Above this temperature it is the most paramagnetic element. It is found in nature only in an oxidized form. When separated, it usually has impurities of the other rare-earths because of their similar chemical properties. Gadolinium was discovered in 1880 by Jean Charles de Marignac, who detected its oxide by using spectroscopy. It is named after the mineral gadolinite, one of the minerals in which gadolinium is found, itself named for the Finnish chemist Johan Gadolin. Pure gadolinium was first isolated by the chemist Paul-Émile Lecoq de Boisbaudran around 1886. Gadoliniu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gadolinium(III) Iodide
Gadolinium(III) iodide is an iodide of gadolinium, with the chemical formula of GdI3. It is a yellow, highly hygroscopic solid with a bismuth(III) iodide-type crystal structure. In air, it quickly absorbs moisture and forms hydrates. The corresponding oxide iodide is also readily formed at elevated temperature. Preparation Gadolinium(III) iodide can be obtained by reacting gadolinium with iodine:Georg Brauer (Hrsg.), unter Mitarbeit von Marianne Baudler u. a.: ''Handbuch der Präparativen Anorganischen Chemie.'' 3., umgearbeitete Auflage. Band I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6, S. 1077. :2 Gd + 3 I2 → 2 GdI3 It can also be obtained by reacting gadolinium with mercury(II) iodide in a vacuum at 500 °C: :2 Gd + 3 HgI2 → 2 GdI3 + 3 Hg Gadolinium(III) iodide can be obtained by the reaction between gadolinium(III) oxide and hydroiodic acid, crystallizing into the hydrate form. The hydrate form can be heated with ammonium iodide to form the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gadolinium Compounds
Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen or moisture slowly to form a black coating. Gadolinium below its Curie point of is ferromagnetic, with an attraction to a magnetic field higher than that of nickel. Above this temperature it is the most paramagnetic element. It is found in nature only in an oxidized form. When separated, it usually has impurities of the other rare-earths because of their similar chemical properties. Gadolinium was discovered in 1880 by Jean Charles de Marignac, who detected its oxide by using spectroscopy. It is named after the mineral gadolinite, one of the minerals in which gadolinium is found, itself named for the Finnish chemist Johan Gadolin. Pure gadolinium was first isolated by the chemist Paul-Émile Lecoq de Boisbaudran around 1886. Gadoliniu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodides
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability. Structure and characteristics of inorganic iodides Iodide is one of the largest monatomic anions. It is assigned a radius of around 206 picometers. For comparison, the lighter halides are considerably smaller: bromide (196 pm), chloride (181 pm), and fluoride (133 pm). In part because of its size, iodide forms relatively weak bonds with most elements. Most iodide salts are soluble in water, but often less so than the related chlorides and bromides. Iodide, being large, is less hydrophilic compared to the smaller anions. One consequence of this is that sodium iodide is highly soluble in acetone, whereas sodium chloride is not. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferromagnetic Materials
Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials are the familiar metals noticeably attracted to a magnet, a consequence of their large magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an ''external'' magnetic field, and it is this temporarily induced magnetization inside a steel plate, for instance, which accounts for its attraction to the permanent magnet. Whether or not that steel plate acquires a permanent magnetization itself, depends not only on the strength of the applied field, but on the so-called coercivity of that material, which varies greatly among ferromagnetic materials. In physics, several different types of material magnetism are distinguished. Ferromagnetism (along with the similar effect ferrimagnetism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
