637 research outputs found

    Naming of new elements(IUPAC Recommendations 2002)

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    A procedure is proposed to name new elements. After the discovery of a new element is established by a joint IUPAC­IUPAP Working Group, the discoverers are invited to propose a name and a symbol to the IUPAC Inorganic Chemistry Division. Elements can be named after a mythological concept, a mineral, a place or country, a property, or a scientist. After examination and acceptance by the Inorganic Chemistry Division, the proposal follows the accepted IUPAC procedure and is then submitted to the IUPAC Council for approva

    Names for inorganic radicals (IUPAC Recommendations 2000)

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    Introduction: Knowledge of the properties and reactivities of stable inorganic radicals was obtained decades ago through gas-phase studies of various oxides of halogens, sulfur, and nitrogen. More recently, pulse radiolysis and flash photolysis techniques developed in the 1960s made it possible to study short-lived radicals, such as hydrated electrons, hydrogen atoms, and hydroxyl radicals. Because of the high time-resolution of these techniques, absorption spectra and redox properties of these inorganic radicals could be determined. The interest in radicals increased when it was shown that superoxide, or dioxide(1-), is formed in vivo. The discovery that in aerobic organisms enzymes catalyze the disproportionation of this radical resulted in new areas of research, such as radical biology and radicals in medicine. Interest in simple radicals was further boosted most recently by the remarkable observation that the radical nitrogen monoxide is formed enzymatically from the amino acid arginine. Radicals are important in a variety of catalytic processes and in the atmospheric gas and liquid phases; furthermore, a substantial number of inorganic radicals have been observed in interstellar gas clouds. Contents: 1. Introduction 2. Definitions 3. Nomenclature 3.1. Introduction 3.2. Coordination nomenclature 3.2.1. Selection of the central atom 3.2.2. Radicals with net charges 3.2.3. Attached atoms or groups of atoms 3.2.4. The radical dot 3.2.5. Examples 3.3. Substitutive nomenclatur

    Names for muonium and hydrogen atoms and their ions(IUPAC Recommendations 2001)

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    Muons are short-lived species with an elementary positive or negative charge and a mass 207 times that of the electron. These recommendations concern positive muons, given the short lifetime of negative muons. A positive muon mimics a light hydrogen nucleus, and names are given in analogy to existing names for hydrogen-containing compounds. A particle consisting of a positive muon and an electron (µ+ e -) is named "muonium" and has the symbol Mu. Examples: "muonium chloride," MuCl, is the equivalent of deuterium chloride, 2 HCl or DCl; "muoniomethane", CH 3 Mu, is the product of the muoniation of methane;and NaMu is "sodium muonide.

    Protein thiyl radical reactions and product formation: a kinetic simulation

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    Protein thiyl radicals are important intermediates generated in redox processes of thiols and disulfides. Thiyl radicals efficiently react with glutathione and ascorbate, and the common notion is that these reactions serve to eliminate thiyl radicals before they can enter potentially hazardous processes. However, over the past years increasing evidence has been provided for rather efficient intramolecular hydrogen transfer processes of thiyl radicals in proteins and peptides. Based on rate constants published for these processes, we have performed kinetic simulations of protein thiyl radical reactivity. Our simulations suggest that protein thiyl radicals enter intramolecular hydrogen transfer reactions to a significant extent even under physiologic conditions, i.e. in the presence of 30 μM oxygen, 1 mM ascorbate and 10 mM glutathione. At lower concentrations of ascorbate and glutathione, frequently observed when tissue is exposed to oxidative stress, the extent of irreversible protein thiyl radical-dependent protein modification increases

    Electron Affinity of Chlorine Dioxide

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    The flowing afterglow technique was used to determine the electron affinity of chlorine dioxide. A value of 2.37 ± 0.10 eV was found by bracketing between the electron affinities of HS° and SF4 as a lower limit and that of NO2 as an upper limit. This value is in excellent agreement with 2.32 eV predicted from a simple thermodynamic cycle involving the reduction potential of the C102/C102- couple and a Gibbs hydration energy identical with that of SO2-

    How to name new chemical elements (IUPAC Recommendations 2016)

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    A procedure is proposed to name new chemical elements. After the discovery of a new element is established by the joint IUPAC-IUPAP Working Group, the discoverers are invited to propose a name and a symbol to the IUPAC Inorganic Chemistry Division. Elements can be named after a mythological concept, a mineral, a place or country, a property or a scientist. After examination and acceptance by the Inorganic Chemistry Division, the proposal follows the accepted IUPAC procedure and is then ratified by the Council of IUPAC. This document is a slightly amended version of the 2002 IUPAC Recommendations; the most important change is that the names of all new elements should have an ending that reflects and maintains historical and chemical consistency. This would be in general “-ium” for elements belonging to groups 1–16, i.e. including the f-block elements, “-ine” for elements of group 17 and “-on” for elements of group 18.This manuscript (PAC-REP-15-08-02) was prepared in the framework of IUPAC project 2015-031-1-200

    Standard electrode potentials involving radicals in aqueous solution: inorganic radicals

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    Inorganic radicals, such as superoxide and hydroxyl, play an important role in biology. Their tendency to oxidize or to reduce other compounds has been studied by pulse radiolysis; electrode potentials can be derived when equilibrium is established with a well-known reference compound. An IUPAC Task Group has evaluated the literature and produced the recommended standard electrode potentials for such couples as (O2/O2·-), (HO·, H+/H2O), (O3/O3·-), (Cl2/Cl2·-), (Br2·-/2Br-), (NO2·/NO2-), and (CO3·-/CO32-
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