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Transition Metal Azide Complex
Transition metal azide complexes are coordination complexes containing one or more azide (N3−) ligands. In addition to coordination complexes, this article summarizes homoleptic transition metal azides, which are often coordination polymers. Structure and bonding Azide is a pseudohalide but more nucleophilic than chloride, as reflected by the higher pKa of hydrazoic acid (4.6) vs hydrochloric acid (-5.9). As a monodentate ligand, azide binds through one of the two terminal nitrogen atoms, i.e. M-N=N=N. Azide is a "pure" sigma donor. It is classified as an X ligand in the Covalent bond classification method. In the usual electron counting method, it is a one-electron ligand. The N3 unit is linear or nearly so. The M-N-N angles are quite bent. Azide functions as a bridging ligand via two bonding modes. Commonly the metals share the same nitrogen ("N-diazonium" mode). Less common is the motif M-N=N=N-M, illustrated by u(N3)(PPh3)2sub>2. General synthetic methods Traditiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSD CIF RIJLAX
CSD may refer to: Finance * Central securities depository * Confederate States Dollar * Serbian dinar The dinar (, ; paucal: dinara / динара; Currency symbol, abbreviation: DIN (Gaj's Latin alphabet, Latin) and дин (Serbian Cyrillic alphabet, Cyrillic); ISO 4217, code: RSD) is the currency of Serbia. The dinar was first used in Serbia in ..., by previous ISO 4217 code Organizations Education * California School for the Deaf (other), several institutions * Canyons School District, in Utah, US * Cheltenham School District, in Pennsylvania, US * Christina School District, in Delaware, US * Cleveland School District, in Mississippi, US * Cordova School District, in Alaska, US Other organizations * Canteen Stores Department (India), a chain of stores operated by the Indian Ministry of Defence at military bases * CSD Pakistan (Canteen Stores Department), a chain of stores operated by the Pakistani Ministry of Defence * Chartered Society of Designers, a British l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Compound
In materials chemistry, a binary phase or binary compound is a chemical compound containing two different elements. Some binary phase compounds are molecular, e.g. carbon tetrachloride (CCl4). More typically binary phase refers to extended solids. Famous examples zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various i ..., which contains zinc and sulfur, and tungsten carbide, which contains tungsten and carbon. Phases with higher degrees of complexity feature more elements, e.g. three elements in ternary phases, four elements in quaternary phases. These phases exhibit a higher degree of complexity due to the interaction of these elements at different conditions. References Chemical compounds {{chem-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2,2′-Bipyridine
2,2′-Bipyridine (bipy or bpy, pronounced ) is an organic compound with the formula . This colorless solid is an important isomer of the bipyridine family. It is a bidentate chelation, chelating ligand, forming complexes with many transition metals. Ruthenium and platinum complexes of bipy exhibit intense luminescence. Preparation, structure, and general properties 2,2'-Bipyridine was first prepared by decarboxylation of divalent metal derivatives of Pyridine-2-carboxylic acid, pyridine-2-carboxylate: It is prepared by the dehydrogenation of pyridine using Raney nickel: Substituted 2,2'-bipyridines Unsymmetrically substituted 2,2'-bipyridines can be prepared by cross coupling reaction of 2-pyridyl and substituted pyridyl reagents. Structure Although bipyridine is often drawn with its nitrogen atoms in ''cis'' conformation, the lowest energy conformation both in solid state and in solution is in fact coplanar, with nitrogen atoms in ''trans'' position. Monoprotonated bipyrid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binding Modes
Binding may refer to: Computing * Binding, associating a network socket with a local port number and IP address * Data binding, the technique of connecting two data elements together ** UI data binding, linking a user interface element to an element of a domain model, such as a database field ** XML data binding, representing XML document data using objects and classes * Key binding, or keyboard shortcut, mapping key combinations to software functionality * Language binding, a library providing a functional interface to second library in a different programming language * Name binding, the association of code or data with an identifier in a programming language ** Late binding, name binding which is resolved at run-time rather than in pre-execution time Science * Binding problem, a term for several problems in cognitive science and philosophy ** Neural binding, synchronous activity of neurons and neuronal ensembles * Molecular binding, an attractive interaction between two mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parent Structure
In chemistry, a parent structure is the structure of an unadorned ion or molecule from which derivatives can be visualized. Parent structures underpin systematic nomenclature and facilitate classification. Fundamental parent structures have one or no functional groups and often have various types of symmetry. Benzene () is a chemical itself consisting of a hexagonal ring of carbon atoms with a hydrogen atom attached to each, and is the parent of many derivatives that have substituent atoms or groups replacing one or more of the hydrogens. Some parents are rare or nonexistent themselves, as in the case of porphine, though many simple and complex derivatives are known. File:Benzene circle.png, Benzene is the parent. File:Toluene-vec.svg, Toluene is a derivative of benzene. File:Porphyrin.svg, Porphine is the parent of porphyrins. File:PPIXtransH.png, Protoporphyrin IX is a natural derivative of the parent porphine. File:H2octaethylporphyrin.png, Octaethylporphyrin is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-crystal X-ray Crystallography
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract in specific directions. By measuring the angles and intensities of the X-ray diffraction, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal and the positions of the atoms, as well as their chemical bonds, crystallographic disorder, and other information. X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences between various materials, especially minerals and alloys. The method has also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins and nucleic acids such as DNA. X-ray crystallography is still the primar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation Potential
Redox potential (also known as oxidation / reduction potential, ''ORP'', ''pe'', ''E_'', or E_) is a measure of the tendency of a chemical species to acquire electrons from or lose electrons to an electrode and thereby be reduced or oxidised respectively. Redox potential is expressed in volts (V). Each species has its own intrinsic redox potential; for example, the more positive the reduction potential (reduction potential is more often used due to general formalism in electrochemistry), the greater the species' affinity for electrons and tendency to be reduced. Measurement and interpretation In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octahedral Molecular Geometry
In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The octahedron has eight faces, hence the prefix '' octa''. The octahedron is one of the Platonic solids, although octahedral molecules typically have an atom in their centre and no bonds between the ligand atoms. A perfect octahedron belongs to the point group Oh. Examples of octahedral compounds are sulfur hexafluoride SF6 and molybdenum hexacarbonyl Mo(CO)6. The term "octahedral" is used somewhat loosely by chemists, focusing on the geometry of the bonds to the central atom and not considering differences among the ligands themselves. For example, , which is not octahedral in the mathematical sense due to the orientation of the bonds, is referred to as octahedral. The concept of octahedral coordination geometry was developed by Alfred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steric Effects
Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is generally a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape (conformational isomerism, conformation) and chemical reaction, reactivity of ions and molecules. Steric effects complement electronic effects, which dictate the shape and reactivity of molecules. Steric repulsive forces between overlapping electron clouds result in structured groupings of molecules stabilized by the way that opposites attract and like charges repel. Steric hindrance Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in ''intermolecular reactions'', whereas discussion of steric effects often focus on ''intramolecular interactions''. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions. Steric hindran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denticity
In coordination chemistry, denticity () refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be unidentate or monodentate. Ligands with more than one bonded atom are called multidentate or polydentate. The denticity of a ligand is described with the Greek letter κ ('kappa'). For example, κ6-EDTA describes an EDTA ligand that coordinates through 6 non-contiguous atoms. Denticity is different from hapticity because hapticity refers exclusively to ligands where the coordinating atoms are contiguous. In these cases the η ('eta') notation is used. Bridging ligands use the μ ('mu') notation. Classes Polydentate ligands are chelating agents and classified by their denticity. Some atoms cannot form the maximum possible number of bonds a ligand could make. In that case one or more binding si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adduct
In chemistry, an adduct (; alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is considered a distinct molecular species. Examples include the addition of sodium bisulfite to an aldehyde to give a sulfonate. It can be considered as a single product resulting from the direct combination of different molecules which comprises all atoms of the reactant molecules. Adducts often form between Lewis acids and Lewis bases. A good example is the formation of adducts between the Lewis acid borane and the oxygen atom in the Lewis bases, tetrahydrofuran (THF): or diethyl ether: . Many Lewis acids and Lewis bases reacting in the gas phase or in non-aqueous solvents to form adducts have been examined in the ECW model. Trimethylborane, trimethyltin chloride and bis(hexafluoroacetylacetonato)copper(II) are examples of Lewi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valence Electron
In chemistry and physics, valence electrons are electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed. In a single covalent bond, a shared pair forms with both atoms in the bond each contributing one valence electron. The presence of valence electrons can determine the element's chemical properties, such as its valence—whether it may bond with other elements and, if so, how readily and with how many. In this way, a given element's reactivity is highly dependent upon its electronic configuration. For a main-group element, a valence electron can exist only in the outermost electron shell; for a transition metal, a valence electron can also be in an inner shell. An atom with a closed shell of valence electrons (corresponding to a noble gas configuration) tends to be chemically inert. Atoms with one or two valence electrons more than a closed shell are highly reactive due to the relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
