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Thiourea
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. " Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea Tautomers
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. "Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea Functional Group
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. "Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioureas
In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula and structure . The parent member of this class of compounds is thiourea (). The thiourea functional group has a planar core. Structure and bonding Thioureas have planar core. The bond distance is near 1.71 Å, which is 0.1 Å longer than in normal ketones (). The C–N bond distances are short. Thioureas occurs in two tautomeric forms. For the parent thiourea, the thione form predominates in aqueous solutions. The thiol form, known as an isothiourea, can be encountered in substituted compounds such as isothiouronium salts. : Synthesis ''N'',''N''′-unsubstituted thioureas can be prepared by treating the corresponding cyanamide with hydrogen sulfide or similar sulfide sources. Organic ammonium salts react with potassium thiocyanate as the source of the thiocarbonyl (). Alternatively, ''N'',''N''′-disubstituted thioureas can be prepared by coupling two ami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea Dioxide
Thiourea dioxide or thiox is an organosulfur compound that is used in the textile industry. It functions as a reducing agent. It is a white solid, and exhibits tautomerism. Structure The structure of thiourea dioxide depends on its environment. Crystalline and gaseous thiourea dioxide adopts a structure with C2v symmetry. Selected bond lengths: S-C = 186, C-N = 130, and S-O = 149 pm. The sulfur center is pyramidal. The C-S bond length is more similar to that of a single bond. For comparison, the C=S bond in thiourea is 171 pm. The long C-S bond indicates the absence of C=S character. Instead the bonding is described with a significant contribution from a dipolar resonance structure with multiple bonding between C and N. One consequence of this bonding is the planarity of the nitrogen centers. In the presence of water or DMSO, thiourea dioxide converts to the tautomer, a sulfinic acid, (H2N)HN=CS(O)(OH), named formamidine sulfinic acid. Synthesis Thiourea dioxide was first prepare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothiouronium
In organic chemistry, isothiouronium is a functional group with the formula SC(NH2)2sup>+ (R = alkyl, aryl) and is the acid salt of isothiourea. The H centres can also be replaced by alkyl and aryl. Structurally, these cations resemble guanidinium cations. The CN2S core is planar and the C–N bonds are short. Synthesis Salts comprising these cations are typically prepared by alkylation of thiourea: :SC(NH2)2 + RX → SC(NH2)2sup>+X− Reactions Hydrolysis of isothiouronium salts gives thiols. : SC(NH2)2sup>+X− + NaOH → RSH + OC(NH2)2 + NaX Isothiouronium salts in which the sulfur has been alkylated, such as ''S''-methylisothiourea hemisulfate (CAS number: 867-44-7), will convert amines into guanidinium groups. This approach is sometimes called the Rathke synthesis after Bernhard Rathke who first reported it in 1881. : RNH2 + eSC(NH2)2sup>+X− → RNC(NH2)2]+X− + MeSH Chelating resins Chelating resins are a class of ion-exchange resins. They are almost always ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Thiocyanate
Ammonium thiocyanate is an inorganic compound with the formula NH4SCN. It is the salt of the ammonium cation and the thiocyanate anion. Uses Ammonium thiocyanate is used in the manufacture of herbicides, thiourea, and transparent artificial resins; in matches; as a stabilizing agent in photography; in various rustproofing compositions; as an adjuvant in textile dyeing and printing; as a tracer in oil fields; in the separation of hafnium from zirconium (important for the production of hafnium-free zircalloy for use in nuclear fuel cladding), and in titrimetric analyses. In May 1945, USAAF General Victor E. Betrandias advanced a proposal to his superior General Arnold to use of ammonium thiocyanate to reduce rice crops in Japan as part of the bombing raids on their country. Ammonium thiocyanate can also be used to determine the iron content in soft drinks by colorimetry. Ammonium thiocyanate may also be used to separate quinidine, from liquors, after the isolation of quinine fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcanization
Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using metal oxides. Vulcanization can be defined as the curing of elastomers, with the terms 'vulcanization' and 'curing' sometimes used interchangeably in this context. It works by forming cross-links between sections of polymer chain which results in increased rigidity and durability, as well as other changes in the mechanical and electrical properties of the material. Vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible. The word vulcanization is derived from Vulcan, the Roman god of fire and forge. History Rubber—latex� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society (professional association) in the United Kingdom with the goal of "advancing the chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 34,000 in the UK and a further 8,000 abroad. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing and Shanghai, China and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods. Historically fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations and byproducts of human-nature industries (i.e. fish processing waste, or bloodmeal fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ullmann's Encyclopedia Of Industrial Chemistry
''Ullmann's Encyclopedia of Industrial Chemistry'' is a major reference work related to industrial chemistry by Chemist Fritz Ullmann, first published in 1914, and exclusively in German as "Enzyklopädie der Technischen Chemie" until 1984. History Ullmann's Encyclopedia of Industrial Chemistry is a major reference work related to industrial chemistry by chemist Fritz Ullmann. Its 1st edition was published in German by Fritz Ullmann in 1914. The 4th edition, published 1972 to 1984, already contained 25 volumes. The 5th edition, published 1985 to 1996, was the first version available in English. In 1997, the first online version was published. 2014 marked its centenary. As of 2016, Ullmann's Encyclopedia was in its 7th edition, in 40 volumes including one index volume and more than 1,050 articles (200 more than the 6th edition), approx. 30,000 pages, 22,000 images, 8,000 tables, 19,000 references and 85,000 indices. Editions * 1914–1922: 1st edition in 12 volumes, which can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Cyanamide
Calcium cyanamide is the inorganic compound with the formula CaCN2. It is the calcium salt of the cyanamide () anion. This chemical is used as fertilizer and is commercially known as nitrolime. It was first synthesized in 1898 by Adolph Frank and Nikodem Caro (Frank–Caro process). History In their search for a new process for producing cyanides for cyanide leaching of gold, Frank and Caro discovered the ability of alkaline earth carbides to absorb atmospheric nitrogen at high temperatures. Fritz Rothe, a colleague of Frank and Caro, succeeded in 1898 in overcoming problems with the use of calcium carbide and clarified that at around 1,100 °C not calcium cyanide but calcium cyanamide is formed in the reaction. In fact, the initial target product sodium cyanide can also be obtained from calcium cyanamide by melting it with sodium chloride in the presence of carbon: : CaCN2 + 2 NaCl + C → 2 NaCN + CaCl2 Frank and Caro developed this reaction for a large-scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
