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Dihydrate
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] |
Cobalt(II) Chloride
Cobalt(II) chloride is an inorganic compound of cobalt and chlorine, with the formula . The compound forms several hydrates ·''n'', for ''n'' = 1, 2, 6, and 9. Claims of the formation of tri- and tetrahydrates have not been confirmed.M. T. Saugier, M. Noailly, R. Cohen-Adad, F. Paulik, and J. Paulik (1977): "Equilibres solide ⇄ liquide ⇆ vapeur du systeme binaire -" ''Journal of Thermal Analysis'', volume 11, issue 1, pages 87–100. Note: the lowest point of fig.6 is inconsistent with fig.7; probably should be at -27.8 C instead of 0 C. The anhydrous form is a blue crystalline solid; the dihydrate is purple and the hexahydrate is pink. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt compounds in the lab. Properties Anhydrous At room temperature, anhydrous cobalt chloride has the cadmium chloride structure () (Rm) in which the cobalt(II) ions are octahedrally coordinated. At about 706 °C (20 degrees below the melting point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt(II) Chloride
Cobalt(II) chloride is an inorganic compound of cobalt and chlorine, with the formula . The compound forms several hydrates ·''n'', for ''n'' = 1, 2, 6, and 9. Claims of the formation of tri- and tetrahydrates have not been confirmed.M. T. Saugier, M. Noailly, R. Cohen-Adad, F. Paulik, and J. Paulik (1977): "Equilibres solide ⇄ liquide ⇆ vapeur du systeme binaire -" ''Journal of Thermal Analysis'', volume 11, issue 1, pages 87–100. Note: the lowest point of fig.6 is inconsistent with fig.7; probably should be at -27.8 C instead of 0 C. The anhydrous form is a blue crystalline solid; the dihydrate is purple and the hexahydrate is pink. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt compounds in the lab. Properties Anhydrous At room temperature, anhydrous cobalt chloride has the cadmium chloride structure () (Rm) in which the cobalt(II) ions are octahedrally coordinated. At about 706 °C (20 degrees below the melting point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trehalose
Trehalose (from Turkish '' tıgala'' – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it as a source of energy, and to survive freezing and lack of water. Extracting trehalose was once a difficult and costly process, but around 2000, the Hayashibara company (Okayama, Japan) discovered an inexpensive extraction technology from starch. Trehalose has high water retention capabilities, and is used in food, cosmetics and as a drug. A procedure developed in 2017 using trehalose allows sperm storage at room temperatures. Structure Trehalose is a disaccharide formed by a bond between two α-glucose units. It is found in nature as a disaccharide and also as a monomer in some polymers. Two other isomers exist, α,β-trehalose, otherwise known as neotrehalose, and β,β-trehalose (also referred to as isotrehalose). Neotrehalose has n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Of Crystallization
In chemistry, water(s) of crystallization or water(s) of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions. In some contexts, water of crystallization is the total mass of water in a substance at a given temperature and is mostly present in a definite ( stoichiometric) ratio. Classically, "water of crystallization" refers to water that is found in the crystalline framework of a metal complex or a salt, which is not directly bonded to the metal cation. Upon crystallization from water, or water-containing solvents, many compounds incorporate water molecules in their crystalline frameworks. Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost. Compared to inorganic salts, proteins crystallize with large amounts of water in the crystal lattice. A water content of 50% is not uncommon for proteins. Applications Knowledge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydration Reaction
In chemistry, a hydration reaction is a chemical reaction in which a substance combines with water. In organic chemistry, water is added to an unsaturated substrate, which is usually an alkene or an alkyne. This type of reaction is employed industrially to produce ethanol, isopropanol, and butan-2-ol.. Organic chemistry Epoxides to glycol Several million tons of ethylene glycol are produced annually by the hydration of oxirane, a cyclic compound also known as ethylene oxide: : C2H4O + H2O → HO–CH2CH2–OH Acid catalysts are typically used. Alkenes For the hydration of alkenes, the general chemical equation of the reaction is the following: :RRC=CH2 + H2O → RRC(OH)-CH3 A hydroxyl group (OH−) attaches to one carbon of the double bond, and a proton (H+) adds to the other. The reaction is highly exothermic. In the first step, the alkene acts as a nucleophile and attacks the proton, following Markovnikov's rule. In the second step an H2O molecule bonds to the other, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethene
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene is widely used in the chemical industry, and its worldwide production (over 150 million tonnes in 2016) exceeds that of any other organic compound. Much of this production goes toward polyethylene, a widely used plastic containing polymer chains of ethylene units in various chain lengths. Ethylene is also an important natural plant hormone and is used in agriculture to force the ripening of fruits. The hydrate of ethylene is ethanol. Structure and properties This hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond. All six atoms that comprise ethylene are coplanar. The H-C-H angle is 117.4°, close to the 120° for ideal sp² hybridized carbon. The molecule is also relatively weak: rota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloral Hydrate
Chloral hydrate is a geminal diol with the formula . It is a colorless solid. It has limited use as a sedative and hypnotic pharmaceutical drug. It is also a useful laboratory chemical reagent and precursor. It is derived from chloral (trichloroacetaldehyde) by the addition of one equivalent of water. History Chloral hydrate was discovered in 1832 by Justus von Liebig in Gießen when a chlorination (halogenation) reaction was performed on ethanol. Its sedative properties were observed by Rudolf Buchheim in 1861, but described in detail and published only in 1869 by Oscar Liebreich; subsequently, because of its easy synthesis, its use became widespread. It was widely used for sedation in asylums and in general medical practice, and also became a popular drug of abuse in the late 19th century. One recreational user was the poet and illustrator Dante Gabriel Rossetti. Chloral hydrate is soluble in both water and ethanol, readily forming concentrated solutions. A solution of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloral
Chloral, also known as trichloroacetaldehyde or trichloroethanal, is the organic compound with the formula Cl3CCHO. This aldehyde is a colourless oily liquid that is soluble in a wide range of solvents. It reacts with water to form chloral hydrate, a once widely used sedative and hypnotic substance. Production Chloral was first prepared, and named, by the German chemist Justus von Liebig in 1832. Liebig treated anhydrous ethanol with dry chlorine gas. Chloral is produced commercially by the chlorination of acetaldehyde in the presence of hydrochloric acid, producing chloral hydrate. Ethanol can also be used as a feedstock. This reaction is catalyzed by antimony trichloride: :H3CCHO + 3 Cl2 + H2O → Cl3CCH(OH)2 + 3 HCl The chloral hydrate is distilled from the reaction mixture. The distillate is then dehydrated with concentrated sulfuric acid, after which the heavier acid layer (containing the water) is drawn off: :Cl3CCH(OH)2 → Cl3CCHO + H2O The resulting product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compounds
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desiccant
A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. They are commonly encountered in foods to retain crispness. Industrially, desiccants are widely used to control the level of water in gas streams. Types of desiccants Although some desiccants are chemically inert, others are extremely reactive and require specialized handling techniques. The most common desiccant is silica gel, an otherwise inert, nontoxic, water-insoluble white solid. Tens of thousands of tons are produced annually for this purpose. Other common desiccants include activated charcoal, calcium sulfate, calcium chloride, and molecular sieves (typically, zeolites). Desiccan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Crystallization
Protein crystallization is the process of formation of a regular array of individual protein molecules stabilized by crystal contacts. If the crystal is sufficiently ordered, it will diffract. Some proteins naturally form crystalline arrays, like aquaporin in the lens of the eye. In the process of protein crystallization, proteins are dissolved in an aqueous environment and sample solution until they reach the supersaturated state. Different methods are used to reach that state such as vapor diffusion, microbatch, microdialysis, and free-interface diffusion. Developing protein crystals is a difficult process influenced by many factors, including pH, temperature, ionic strength in the crystallization solution, and even gravity. Once formed, these crystals can be used in structural biology to study the molecular structure of the protein, particularly for various industrial or medical purposes. Development of protein crystallization For over 150 years, scientists from all arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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