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Copper(II) Fluoride
Copper(II) fluoride is an inorganic compound with the chemical formula CuF2. The anhydrous form is a white, ionic, crystalline, hygroscopic solid with a distorted rutile-type crystal structure, similar to other fluorides of chemical formulae MF2 (where M is a metal). The dihydrate, , is blue in colour. Structure Copper(II) fluoride has a monoclinic crystal structure and cannot achieve a higher-symmetry structure. It forms rectangular prisms with a parallelogram base. Each copper ion has four neighbouring fluoride ions at 1.93 Å separation and two further away at 2.27 Å. This distorted octahedral +2 coordination is a consequence of the Jahn–Teller effect in d9 copper(II), and leads to a distorted rutile structure similar to that of chromium(II) fluoride, , which is a d4 compound. Uses Copper (II) fluoride can be used to make fluorinated aromatic hydrocarbons by reacting with aromatic hydrocarbons in an oxygen-containing atmosphere at temperatures above 450 °C (84 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unit Cell
In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessarily have unit size, or even a particular size at all. Rather, the primitive cell is the closest analogy to a unit vector, since it has a determined size for a given lattice and is the basic building block from which larger cells are constructed. The concept is used particularly in describing crystal structure in two and three dimensions, though it makes sense in all dimensions. A lattice can be characterized by the geometry of its unit cell, which is a section of the tiling (a parallelogram or parallelepiped) that generates the whole tiling using only translations. There are two special cases of the unit cell: the primitive cell and the conventional cell. The primitive cell is a unit cell corresponding to a single lattice point, it is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic Crystal System
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal classes The table below organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandmeyer Reaction
The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation. : The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer, when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I) acetylide. Instead, the main product he isolated was chlorobenzene. In modern times, the Sandmeyer reaction refers to any method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile in the presence of catalytic copper(I) salts. (Due to the low cost of copper salts, a stoichiometric amount is often employed for better reactivity even when catalysis is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromatic Hydrocarbon
Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past grouping of molecules based on smell, before their general chemical properties are understood. The current definition of aromatic compounds does not have any relation with their smell. Heteroarenes are closely related, since at least one carbon atom of CH group is replaced by one of the heteroatoms oxygen, nitrogen, or sulfur. Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one nitrogen atom. Hydrocarbons without an aromatic ring are called aliphatic. Benzene ring model Benzene, C6H6, is the least complex aromatic hydrocarbon, and it was the first one named as such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(II)-fluoride-F-coord-3D-bs-17
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. 350 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(II)-fluoride-Cu-coord-3D-bs-17
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. 350 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium(II) Fluoride
Chromium(II) fluoride is an inorganic compound with the formula CrF2. It exists as a blue-green iridescent solid. Chromium(II) fluoride is sparingly soluble in water, almost insoluble in alcohol, and is soluble in boiling hydrochloric acid, but is not attacked by hot distilled sulfuric acid or nitric acid. Like other chromous compounds, chromium(II) fluoride is oxidized to chromium(III) oxide in air. Preparation and structure The compound is prepared by passing anhydrous hydrogen fluoride over anhydrous chromium(II) chloride. The reaction will proceed at room temperature but is typically heated to 100-200 °C to ensure completion: :CrCl2 + 2 HF → CrF2 + 2 HCl Like many difluorides, CrF2 adopts a structure like rutile with octahedral molecular geometry about Cr(II) and trigonal geometry at F−. Two of the six Cr–F bonds are long at 2.43 Å, and four are short near 2.00 Å. This distortion is a consequence of the Jahn–Teller effect that arises from the d4 el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D Electron Count
The d electron count is a chemistry formalism used to describe the electron configuration of the valence electrons of a transition metal center in a coordination complex. The d electron count is an effective way to understand the geometry and reactivity of transition metal complexes. The formalism has been incorporated into the two major models used to describe coordination complexes; crystal field theory and ligand field theory, which is a more advanced version based on molecular orbital theory. Standard electron configuration perspective The electron configuration for transition metals predicted by the simple Aufbau principle and Madelung's rule has serious conflicts with experimental observations for transition metal centers under most ambient conditions. Under most conditions all of the valence electrons of a transition metal center are located in d orbitals while the standard model of electron configuration would predict some of them to be in the pertinent s orbital. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jahn–Teller Effect
The Jahn–Teller effect (JT effect or JTE) is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in spectroscopy, stereochemistry, crystal chemistry, molecular and solid-state physics, and materials science. The effect is named for Hermann Arthur Jahn and Edward Teller, who first reported studies about it in 1937.Bunker, Philip R.; Jensen, Per (1998) ''Molecular Symmetry and Spectroscopy'' (2nd ed.). NRC Research Press, Ottaw/ref> Simplified overview The Jahn–Teller effect, sometimes also referred to as Jahn–Teller distortion, describes the geometrical distortion of molecules and ions that result from certain electron configurations. The Jahn–Teller theorem essentially states that any non-linear molecule with a spatially degenerate energy level, degenerate electronic ground state will undergo a geometrical distortion that removes th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Geometry
The term coordination geometry is used in a number of related fields of chemistry and solid state chemistry/physics. Molecules The coordination geometry of an atom is the geometrical pattern formed by atoms around the central atom. Inorganic coordination complexes In the field of inorganic coordination complexes it is the geometrical pattern formed by the atoms in the ligands that are bonded to the central atom in a molecule or a coordination complex. The geometrical arrangement will vary according to the number and type of ligands bonded to the metal centre, and to the coordination preference of the central atom, typically a metal in a coordination complex. The number of atoms bonded, (i.e. the number of σ-bonds between central atom and ligands) is termed the coordination number. The geometrical pattern can be described as a polyhedron where the vertices of the polyhedron are the centres of the coordinating atoms in the ligands. The coordination preference of a metal often va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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