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Chromium(II) Sulfide
Chromium(II) sulfide is an inorganic compound of chromium and sulfur with the chemical formula CrS. The compound forms black hexagonal crystals, insoluble in water. Synthesis Chromium(II) sulfide may be formed by reaction of chromium metal with sulfur or hydrogen sulfide at high temperature. It may also be formed by reacting chromium(III) chloride with H2S, reducing chromium(III) sulfide with hydrogen, or by double replacement reaction of lithium sulfide with chromium(II) chloride Chromium(II) chloride describes inorganic compounds with the chemical formula, formula Chromium, CrChlorine, Cl2(H2O)n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily disso .... ::Cr + S -> CrS ::Cr + H2S -> CrS + H2 ::2CrCl3 + 3H2S -> 2CrS + S + 6HCl ::Cr2S3 + H2 -> 2CrS + H2S ::Li2S + CrCl2 -> 2LiCl + CrS Physical properties Chromium(II) sulfide forms black paramagnetic crystals of two crystalline modifications: *α- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(III) Sulfide
Chromium(III) sulfide is the inorganic compound with the formula chromium, Cr2sulfide, S3. It is a brown-black solid. Chromium sulfides are usually nonstoichiometric compounds, with formulas ranging from CrS to Cr0.67S (corresponding to Cr2S3). Preparation Chromium(III) sulfide can be prepared through the reaction of a stoichiometric mixture of the elements at 1000 °CGeorg Brauer: Handbuch der präparativen anorganischen Chemie. 3., umgearb. Auflage. Band III. Enke, Stuttgart 1981, , S. 1493 :\mathrm It is a solid that is insoluble in water. According to X-ray crystallography, its structure is a combination of that of nickel arsenide (1:1 stoichiometry) and Cadmium hydroxide, Cd(OH)2 (1:2 stoichiometry). Some metal-metal bonding is indicated by the short Cr-Cr distance of 2.78 Å. Jellinek, F. "The structures of the Chromium Sulphides" Acta Crystallographica 1957, volume 10, p620-p628 See also * Brezinaite, a mineral with the formula Cr3S4 References Chromium(II ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(III) Sulfide
Chromium(III) sulfide is the inorganic compound with the formula chromium, Cr2sulfide, S3. It is a brown-black solid. Chromium sulfides are usually nonstoichiometric compounds, with formulas ranging from CrS to Cr0.67S (corresponding to Cr2S3). Preparation Chromium(III) sulfide can be prepared through the reaction of a stoichiometric mixture of the elements at 1000 °CGeorg Brauer: Handbuch der präparativen anorganischen Chemie. 3., umgearb. Auflage. Band III. Enke, Stuttgart 1981, , S. 1493 :\mathrm It is a solid that is insoluble in water. According to X-ray crystallography, its structure is a combination of that of nickel arsenide (1:1 stoichiometry) and Cadmium hydroxide, Cd(OH)2 (1:2 stoichiometry). Some metal-metal bonding is indicated by the short Cr-Cr distance of 2.78 Å. Jellinek, F. "The structures of the Chromium Sulphides" Acta Crystallographica 1957, volume 10, p620-p628 See also * Brezinaite, a mineral with the formula Cr3S4 References Chromium(II ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter De Gruyter
Walter de Gruyter GmbH, known as De Gruyter (), is a German scholarly publishing house specializing in academic literature. History The roots of the company go back to 1749 when Frederick the Great granted the Königliche Realschule in Berlin the royal privilege to open a bookstore and "to publish good and useful books". In 1800, the store was taken over by Georg Reimer (1776–1842), operating as the ''Reimer'sche Buchhandlung'' from 1817, while the school’s press eventually became the ''Georg Reimer Verlag''. From 1816, Reimer used the representative Sacken'sche Palace on Berlin's Wilhelmstraße for his family and the publishing house, whereby the wings contained his print shop and press. The building became a meeting point for Berlin salon life and later served as the official residence of the president of Germany. Born in Ruhrort in 1862, Walter de Gruyter took a position with Reimer Verlag in 1894. By 1897, at the age of 35, he had become sole proprietor of the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PubChem
PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information (NCBI), a component of the National Library of Medicine, which is part of the United States National Institutes of Health (NIH). PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be freely downloaded via FTP. PubChem contains multiple substance descriptions and small molecules with fewer than 100 atoms and 1,000 bonds. More than 80 database vendors contribute to the growing PubChem database. History PubChem was released in 2004 as a component of the Molecular Libraries Program (MLP) of the NIH. As of November 2015, PubChem contains more than 150 million depositor-provided substance descriptions, 60 million unique chemical structures, and 225 million biological activity test results (from over 1 million assay experiments performed on more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Library Of Medicine
The United States National Library of Medicine (NLM), operated by the United States federal government, is the world's largest medical library. Located in Bethesda, Maryland, the NLM is an institute within the National Institutes of Health. Its collections include more than seven million books, journals, technical reports, manuscripts, microfilms, photographs, and images on medicine and related sciences, including some of the world's oldest and rarest works. The current director of the NLM is Patricia Flatley Brennan.National Library of Medicine Welcomes New Director Dr. Patricia Flatley Brennan . ''National Library of Medicine''. August 15, 2016. History The precursor o ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(II) Chloride
Chromium(II) chloride describes inorganic compounds with the formula Cr Cl2(H2O)n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily dissolves in water to give bright blue air-sensitive solutions of the tetrahydrate Cr(H2O)4Cl2. Chromium(II) chloride has no commercial uses but is used on a laboratory-scale for the synthesis of other chromium complexes. Synthesis CrCl2 is produced by reducing chromium(III) chloride either with hydrogen at 500 °C: :2CrCl3 + H2 → 2CrCl2 + 2HCl or by electrolysis. On the laboratory scale, LiAlH4, zinc, and related reductants produce chromous chloride from chromium(III) precursors: :4 CrCl3 + LiAlH4 → 4 CrCl2 + LiCl + AlCl3 + 2 H2 :2 CrCl3 + Zn → 2 CrCl2 + ZnCl2 CrCl2 can also be prepared by treating a solution of chromium(II) acetate with hydrogen chloride: :Cr2(OAc)4 + 4 HCl → 2 CrCl2 + 4 AcOH Treatment of chromium powder with concentrated hydrochloric aci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Sulfide
Lithium sulfide is the inorganic compound with the formula Li2 S. It crystallizes in the antifluorite motif, described as the salt (Li+)2S2−. It forms a solid yellow-white deliquescent powder. In air, it easily hydrolyses to release hydrogen sulfide (rotten egg odor). Preparation Lithium sulfide is prepared by treating lithium with sulfur. This reaction is conveniently conducted in anhydrous ammonia. :2 Li + S → Li2S The THF-soluble triethylborane adduct of lithium sulfide can be generated using superhydride Lithium triethylborohydride is the organoboron compound with the formula Li Et3 BH. Commonly referred to as LiTEBH or Superhydride, it is a powerful reducing agent used in organometallic and organic chemistry. It is a colorless or white liquid bu .... Reactions and applications Lithium sulfide has been considered for use in lithium–sulfur batteries. References External links Lithium Sulfide {{Sulfides Lithium salts Sulfides Fluorite crystal structure [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Replacement Reaction
A salt metathesis reaction, sometimes called a double displacement reaction, is a chemical process involving the exchange of chemical bond, bonds between two reacting chemical species which results in the creation of products with similar or identical bonding affiliations. This reaction is represented by the general scheme: :AB + CD -> AD + CB The bond between the reacting species can be either Ionic bonding, ionic or Covalent bond, covalent. Classically, these reactions result in the precipitation of one product. In older literature, the term double decomposition is frequently encountered. The term double decomposition is more specifically used when at least one of the substances does not dissolve in the solvent, as the ligand or ion exchange takes place in the solid state of the reactant. For example: :AX(aq) + BY(s) → AY(aq) + BX(s). Types of reactions Counterion exchange Salt metathesis is a common technique for exchanging counterions. The choice of reactants is guid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(III) Chloride
Chromium(III) chloride (also called chromic chloride) describes any of several chemical compounds with the formula CrCl3, where can be 0, 5, and 6. The anhydrous compound with the formula CrCl3 is a violet solid. The most common form of the trichloride is the dark green hexa hydrate, CrCl3. Chromium chlorides find use as catalysts and as precursors to dyes for wool. Structure Anhydrous chromium(III) chloride adopts the YCl3 structure, with Cr3+ occupying one third of the octahedral interstices in alternating layers of a pseudo- cubic close packed lattice of Cl− ions. The absence of cations in alternate layers leads to weak bonding between adjacent layers. For this reason, crystals of CrCl3 cleave easily along the planes between layers, which results in the flaky ( micaceous) appearance of samples of chromium(III) chloride. If pressurized to 9.9 GPa it goes under a phase transition. File:Chromium(III)-chloride-sheet-from-monoclinic-xtal-3D-balls-SF-overlay.png, Space-fill ... [...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] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is ''stinkdamp''. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or it or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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