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Copper Acetylide
Copper(I) acetylide, or cuprous acetylide, is a chemical compound with the formula Cu2 C2. Although never characterized by X-ray crystallography, the material has been claimed at least since 1856. One form is claimed to be a mono hydrate with formula .. It is a reddish solid, that easily explodes when dry. Synthesis Materials purported to be copper acetylide can be prepared by treating acetylene with a solution of copper(I) chloride and ammonia: :C2H2 (g) + 2 CuCl (s) → Cu2C2 (s) + 2 HCl (g) This reaction produces a reddish solid precipitate. Properties When dry, copper acetylide is a heat and shock sensitive high explosive, more thermally sensitive than silver acetylide. Copper acetylide is thought to form inside pipes made of copper or an alloy with high copper content, which may result in violent explosion. This was found to be the cause of explosions in acetylene plants, and led to abandonment of copper as a construction material in such plants. Copper catalysts use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium
The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations (), where one or more hydrogen atoms are replaced by organic groups (indicated by R). Acid–base properties The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted acids (proton donors): :H+ + NH3 -> H4 The ammonium ion is mildly acidic, reacting with Brønsted bases to return to the uncharged ammonia molecule: : H4 + B- -> HB + NH3 Thus, treatment of concentrated solutions of ammonium salts with strong base gives ammonia. When ammonia is dissolved in water, a tiny amount of it converts to ammonium ions: :H2O + NH3 OH- + H4 The degree to which ammonia forms the ammonium ion depends on the pH of the solution. If the pH is low, the equilibrium shifts to the right: more ammonia molecules ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(I) Compounds
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable metallic form (native metals). This led to very early human use in several regions, from circa 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, circa 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create bronze, c. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkynation
In organic chemistry, alkynylation is an addition reaction in which a terminal alkyne () is added to a carbonyl group () to form an α-alkynyl alcohol (). When the acetylide is formed from acetylene (), the reaction gives an α- ethynyl alcohol. This process is often referred to as ethynylation. Such processes often involve metal acetylide intermediates. Scope The principal reaction of interest involves the addition of the acetylene () to a ketone () or aldehyde (): :RR'C=O + HC#CR'' -> RR'C(OH)C#CR'' The reaction proceeds with retention of the triple bond. For aldehydes and unsymmetrical ketones, the product is chiral, hence there is interest in asymmetric variants. These reactions invariably involve metal-acetylide intermediates. This reaction was discovered by chemist John Ulric Nef in 1899 while experimenting with reactions of elemental sodium, phenylacetylene, and acetophenone. For this reason, the reaction is sometimes referred to as Nef synthesis. Sometimes this r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Reppe
Walter Julius Reppe (29 July 1892 in Göringen – 26 July 1969 in Heidelberg) was a German chemist. He is notable for his contributions to the chemistry of acetylene. Education and career Walter Reppe began his study of the natural sciences University of Jena in 1911. Interrupted by the First World War, he obtained his doctorate in Munich in 1920. In 1921, Reppe worked for BASF's main laboratory. From 1923, he worked on the catalytic dehydration of formamide to prussic acid in the indigo laboratory, developing this procedure for industrial use. In 1924, he left research for 10 years, only resuming it in 1934. Acetylene chemistry Reppe began his interest in acetylene in 1928. Acetylene is a gas which can take part in many chemical reactions. However, it is explosive and accidents often occurred. Because of this danger, small quantities of acetylene were used at a time, and always without high pressures. In fact, it was forbidden to compress acetylene over 1.5 bar at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbide
In chemistry, a carbide usually describes a compound composed of carbon and a metal. In metallurgy, carbiding or carburizing is the process for producing carbide coatings on a metal piece. Interstitial / Metallic carbides The carbides of the group 4, 5 and 6 transition metals (with the exception of chromium) are often described as interstitial compounds. These carbides have metallic properties and are refractory. Some exhibit a range of stoichiometries, being a non-stoichiometric mixture of various carbides arising due to crystal defects. Some of them, including titanium carbide and tungsten carbide, are important industrially and are used to coat metals in cutting tools. The long-held view is that the carbon atoms fit into octahedral interstices in a close-packed metal lattice when the metal atom radius is greater than approximately 135 pm: *When the metal atoms are cubic close-packed, (ccp), then filling all of the octahedral interstices with carbon achieves 1:1 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulene
In organic chemistry, a cumulene is a compound having three or more ''cumulative'' (consecutive) double bonds. They are analogous to allenes, only having a more extensive chain. The simplest molecule in this class is butatriene (), which is also called simply ''cumulene''. Unlike most alkanes and alkenes, cumulenes tend to be rigid, comparable to polyynes. Cumulene carbenes for ''n'' from 3 to 6 have been observed in interstellar molecular clouds and in laboratory experiments by using microwave and infrared spectroscopy. (The more stable cumulenes are difficult to detect optically because they lack an electric dipole moment.) Cumulenes containing heteroatoms are called heterocumulenes; an example is carbon suboxide. Synthesis The first reported synthesis of a butatriene is that of tetraphenylbutatriene in 1921. The most common synthetic method for butatriene synthesis is based on reductive coupling of a geminal dihalo vinylidene. Tetraphenylbutatriene was reported synt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylide
In organometallic chemistry, acetylide refers to chemical compounds with the chemical formulas and , where M is a metal. The term is used loosely and can refer to substituted acetylides having the general structure (where R is an organic side chain). Acetylides are reagents in organic synthesis. The calcium acetylide commonly called calcium carbide is a major compound of commerce. Structure and bonding Alkali metal and alkaline earth metal acetylides of the general formula MC≡CM are salt-like Zintl phase compounds, containing ions. Evidence for this ionic character can be seen in the ready hydrolysis of these compounds to form acetylene and metal oxides, there is also some evidence for the solubility of ions in liquid ammonia. The ion has a closed shell ground state of 1Σ, making it isoelectronic to a neutral molecule N2, which may afford it some stability. Analogous acetylides prepared from other metals, particularly transition metals, show covalent character and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrochloric Acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a proton, H+, and an anion, A-. The dissociation of a strong acid in solution is effectively complete, except in its most concentrated solutions .... It is a component of the gastric acid in the digestive systems of most animal species, including humans. Hydrochloric acid is an important laboratory reagent and industrial chemical. History In the early tenth century, the Persian physician and alchemist Abu Bakr al-Razi ( 865–925, Latin: Rhazes) conducted experiments with sal ammoniac (ammonium chloride) and vitriol (hydrated sulfates of various metals), which he distilled together, thus producing the gas hydrogen chloride. In doing so, al-Razi may have stumbled upon a primitive method ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allotrope
Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical State of matter, state, known as allotropes of the elements. Allotropes are different structural modifications of an element: the atoms of the element are Chemical bond, bonded together in a different manner. For example, the allotropes of carbon include diamond (the carbon atoms are bonded together to form a Cubic crystal system, cubic lattice of Tetrahedral molecular geometry, tetrahedra), graphite (the carbon atoms are bonded together in sheets of a hexagonal lattice), graphene (single sheets of graphite), and fullerenes (the carbon atoms are bonded together in spherical, tubular, or ellipsoidal formations). The term ''allotropy'' is used for elements only, not for Chemical compound, compounds. The more general term, used for any compound, is Polymorphism (materials science), polymorphism, although its use is usually restricted to solid materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Acetylenic Carbon
Linear acetylenic carbon (LAC), also known as carbyne or Linear Carbon Chain (LCC), is an allotrope of carbon that has the chemical structure as a repeat unit, with alternating single and triple bonds. It would thus be the ultimate member of the polyyne family. This polymeric carbyne is of considerable interest to nanotechnology as its Young's modulus is – forty times that of diamond; this extraordinary number is, however, based on a novel definition of cross-sectional area that does not correspond to the space occupied by the structure. Carbyne has also been identified in interstellar space; however, its existence in condensed phases has been contested recently, as such chains would crosslink exothermically (and perhaps explosively) if they approached each other. History and controversy The first claims of detection of this allotrope were made in 1960Sladkov A.M, Kudryavtsev Y.P Diamond, graphite, carbyne 3/4 the allotropic forms of carbon, Priroda (Nature), 1969, 58:3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Compound
A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the Periodic Table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom through several of the ligand's atoms; ligands with 2, 3, 4 or even 6 bonds to the central atom are common. These com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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