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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, and are Mott insulators. Properties of these salts have been analyzed. ThI2 and ThI3 have also been repor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lanthanide
The lanthanide () or lanthanoid () series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare-earth elements or rare-earth metals. The informal chemical symbol Ln is used in general discussions of lanthanide chemistry to refer to any lanthanide. All but one of the lanthanides are f-block elements, corresponding to the filling of the 4f electron shell. There is some dispute on whether lanthanum or lutetium is a d-block element, but lutetium is usually considered so by those who study the matter; it is included due to its chemical similarities with the other 14. All lanthanide elements form trivalent cations, Ln3+, whose chemistry is largely determined by the ionic radius, which decreases steadily from lanthanum to lutetium. These elements are called lanthanides because the eleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvated Electron
A solvated electron is a free electron in (solvated in) a solution, and is the smallest possible anion. Solvated electrons occur widely. Often, discussions of solvated electrons focus on their solutions in ammonia, which are stable for days, but solvated electrons also occur in water and other solvents in fact, in any solvent that mediates outer-sphere electron transfer. The solvated electron is responsible for a great deal of radiation chemistry. Ammonia solutions Liquid ammonia will dissolve all of the alkali metals and other electropositive metals such as Ca, Sr, Ba, Eu, and Yb (also Mg using an electrolytic process), giving characteristic blue solutions. For alkali metals in liquid ammonia, the solution is blue when dilute and copper-colored when more concentrated (> 3 molar). These solutions conduct electricity. The blue colour of the solution is due to ammoniated electrons, which absorb energy in the visible region of light. The diffusivity of the solvated elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disodium Helide
Disodium helide (Na2He) is a compound of helium and sodium that is stable at high pressures above . It was first predicted using the USPEX crystal structure prediction algorithm and then synthesised in 2016. Synthesis Na2He was predicted to be thermodynamically stable over 160 GPa and dynamically stable over 100 GPa. This means it should be possible to form at the higher pressure and then decompress to 100 GPa, but below that it would decompose. Compared with other binary compounds of other elements and helium, it was predicted to be stable at the lowest pressure of any such combination. This also means, for example, that a helium-potassium compound is predicted to require much higher pressures of the order of terapascals. The material was synthesized by putting tiny plates of sodium in a diamond anvil cell along with helium at 1600 bar and then compressing to 130 GPa and heating to 1,500 K with a laser. Disodium helide is predicted to be an insulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Metal
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names for the elements in some languages, such as German and Russian. rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Amide
Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. has been widely employed as a strong base in organic synthesis. Preparation and structure Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia, c. −33 °C. An electride, , is formed as a reaction intermediate. : is a salt-like material and as su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birch Reduction
The Birch reduction is an organic reaction that is used to convert arenes to cyclohexadienes. The reaction is named after the Australian chemist Arthur Birch and involves the organic reduction of aromatic rings in an amine solvent (traditionally liquid ammonia) with an alkali metal (traditionally sodium) and a proton source (traditionally an alcohol). Unlike catalytic hydrogenation, Birch reduction does not reduce the aromatic ring all the way to a cyclohexane. An example is the reduction of naphthalene in ammonia and ethanol: Reaction mechanism and regioselectivity A solution of sodium in liquid ammonia consists of the intensely blue electride salt a(NH3)xsup>+ e−. The solvated electrons add to the aromatic ring to give a radical anion, which then abstracts a proton from the alcohol. The process then repeats at either the ''ortho'' or ''para'' position (depending on substituents) to give the final diene. The residual double bonds do not stabilize further radi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salts
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions. The component ions in a salt compound can be either inorganic, such as chloride (Cl−), or organic, such as acetate (). Each ion can be either monatomic, such as fluoride (F−), or polyatomic, such as sulfate (). Types of salt Salts can be classified in a variety of ways. Salts that produce hydroxide ions when dissolved in water are called '' alkali salts'' and salts that produce hydrogen ions when dissolved in water are called '' acid salts''. ''Neutral salts'' are those salts that are neither acidic nor basic. Zwitterions contain an anionic and a cationic centre in the same molecule, but are not considered salts. Examples of zwitterions are amino acids, many metabolites, pept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F-center
An F center or Farbe center (from the original German ''Farbzentrum'', where ''Farbe'' means ''color'' and ''zentrum'' means center) is a type of crystallographic defect in which an anionic vacancy in a crystal lattice is occupied by one or more unpaired electrons. Electrons in such a vacancy in a crystal lattice tend to absorb light in the visible spectrum such that a material that is usually transparent becomes colored. The greater the number of F centers, the more intense the color of the compound. F centers are a type of color center. This is used to identify many compounds, especially zinc oxide (yellow). History Before the discovery of point defects it was already known that some crystals can be discolored using various methods. In 1830 T.J. Pearsall discovered that fluorspar could be discolored using violet light. Thirty years later similar results were achieved by melting crystals together with a specific metal. In 1921 W. Röntgen extensively measured rock salts. One set ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-layer Materials
In materials science, the term single-layer materials or 2D materials refers to crystalline solids consisting of a single layer of atoms. These materials are promising for some applications but remain the focus of research. Single-layer materials derived from single elements generally carry the -ene suffix in their names, e.g. graphene. Single-layer materials that are compounds of two or more elements have -ane or -ide suffixes. 2D materials can generally be categorized as either 2D allotropes of various elements or as compounds (consisting of two or more covalently bonding elements). It is predicted that there are hundreds of stable single-layer materials. The atomic structure and calculated basic properties of these and many other potentially synthesisable single-layer materials, can be found in computational databases. 2D materials can be produced using mainly two approaches: top-down exfoliation and bottom-up synthesis. The exfoliation methods include sonication, mechanical, h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Reports
''Scientific Reports'' is a peer-reviewed open-access scientific mega journal published by Nature Portfolio, covering all areas of the natural sciences. The journal was established in 2011. The journal states that their aim is to assess solely the scientific validity of a submitted paper, rather than its perceived importance, significance, or impact. In September 2016, the journal became the largest in the world by number of articles, overtaking '' PLOS ONE''. Abstracting and indexing The journal is abstracted and indexed in the Chemical Abstracts Service, the Science Citation Index Expanded, and selectively in Index Medicus/MEDLINE/PubMed. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor 4.996. Reviewing policy The ''Guide to Referees'' states that to be published, "a paper must be scientifically valid and technically sound in methodology and analysis", and reviewers have to ensure manuscripts "are not assessed based on their perceived impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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