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Halogen

About: Halogen is a research topic. Over the lifetime, 6789 publications have been published within this topic receiving 110903 citations. The topic is also known as: group 17 elements & halogens.


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Journal ArticleDOI
31 Aug 2001-Science
TL;DR: A two-electron mixed-valence dirhodium compound is used to photocatalyze the reduction of hydrohalic acid to hydrogen in a cycle to promote the production of hydrogen from homogeneous solution.
Abstract: Energy conversion cycles are aimed at driving unfavorable, small-molecule activation reactions with a photon harnessed by a transition metal complex. A challenge that has occupied researchers for several decades is to create molecular photocatalysts to promote the production of hydrogen from homogeneous solution. We now report the use of a two-electron mixed-valence dirhodium compound to photocatalyze the reduction of hydrohalic acid to hydrogen. In this cycle, photons break two RhII–X bonds of a LRh0–RhIIX2 core in the presence of a halogen trap to regenerate the active LRh0–Rh0 catalyst, which reacts with hydrohalic acid to produce hydrogen.

293 citations

Journal ArticleDOI
TL;DR: In this paper, a survey of halogen bonding involving at least one inorganic (metal-containing) component is presented, with the focus on inorganic components, or at least metal-containing components, and their propensity to form halogen bonds.
Abstract: Halogen bonds in the solid state have been investigated for many years, with a major resurgence in activity occurring in the past decade. The emphasis of most studies has been on organic components. This Highlight focusses on inorganic components, or at least metal-containing components, and explores their propensity to form halogen bonds. The use of C–X⋯X′–M halogen bonds in forming networks is briefly reviewed and their utility in investigating the nature of halogen bonds is explored since their strength can be tuned by changing either the organic (donor) halogen (C–X) or the inorganic (acceptor) halogen (M–X′). A survey has been performed of crystal structures in which interactions are of suitable geometry to be considered as halogen bonds. In particular the role of simple monatomic (e.g.oxo, nitrido) and diatomic (e.g.carbonyl, cyanide) ligands as halogen bond acceptors in transition metal complexes is examined. Main group metals are also considered in a further section that considers D–X⋯A–M halogen bonds, where D = halogen bond donor, A = halogen bond acceptor and M = main group metal or metalloid. Many examples presented herein were not identified as halogen bonds in the original articles. The aim of this survey is to examine the breadth of elements that can be involved in halogen bonding involving at least one inorganic (metal-containing) component and consider this range of interactions as a basis for future research in halogen bonding with applications in crystal engineering and allied areas.

282 citations

Journal ArticleDOI
02 Jan 1998-Science
TL;DR: This study shows that molecular chlorine is generated from the photolysis of ozone in the presence of sea-salt particles above their deliquescence point; this process may also occur in the ocean surface layer.
Abstract: Halogen atoms from the reactions of sea-salt particles may play a significant role in the marine boundary layer. Reactions of sodium chloride, the major component of sea-salt particles, with nitrogen oxides generate chlorine atom precursors. However, recent studies suggest there is an additional source of chlorine in the marine troposphere. This study shows that molecular chlorine is generated from the photolysis of ozone in the presence of sea-salt particles above their deliquescence point; this process may also occur in the ocean surface layer. Given the global distribution of ozone, this process may provide a global source of chlorine.

281 citations

Journal ArticleDOI
TL;DR: In this article, the authors show the participation of rare gas atom(s) in these new compounds, based on studies of the thermally generated species in mixed rare gas matrices, and their vibrational spectra are discussed and compared with those calculated with ab initio methods.
Abstract: Ultraviolet‐irradiation of hydrogen halide containing rare gas matrices yields the formation of linear centrosymmetric cations of type (XHX)+, (X=Ar, Kr, Xe). Annealing of the irradiated doped solids produces, along with thermoluminescence, extremely strong absorptions in the 1700–1000 cm−1 region. Based on isotopic substitution and halogen dependence of these bands, the presence of hydrogen and halogen atom(s) in these species is evident. In the present paper we show the participation of rare gas atom(s) in these new compounds. The evidence is based on studies of the thermally generated species in mixed rare gas matrices. The new species are assigned as neutral charge‐transfer molecules HX+Y− (Y=halogen), and their vibrational spectra are discussed and compared with those calculated with ab initio methods. This is the first time hydrogen and a rare gas atom has been found to make a chemical bond in a neutral stable compound. The highest level ab initio calculations on the existence of compounds of type HXY corroborate the experimental observations. The mechanism responsible for the formation of these species is also discussed.

268 citations

Journal ArticleDOI
TL;DR: In this article, the dipole strengths for certain perpendicular-type transitions N→Q in the mixed halogens, the hydrogen and monovalent metal halides, and the alkyl halides are calculated theoretically by the LCAO and by the AO approximations.
Abstract: The dipole strengths for certain perpendicular‐type transitions N→Q in the mixed halogens, the hydrogen and monovalent metal halides, and the alkyl halides, are calculated theoretically by the LCAO and by the AO approximations. The scanty experimental absorption coefficient data on these halides (particularly the hydrogen and alkyl bromides and iodides) are critically examined, and acceptable experimental dipole strengths are obtained for the bromides. These show, very gratifyingly, the same kind of agreement with the calculated values as was found in IX of this series for the N→Q transitions in F2, Cl2, and Br2. The iodides, however, just like I2, show anomalously low strengths for the true N→Q part of the intensity (N→3II1 and N→1II), together with high strength for N→3II0+. These anomalies are ascribed here, as in I2, to partial case c coupling (partial preservation of atomic J's). The comparison between theory and experiment confirms the interpretation of the ultraviolet continua of the hydrogen and a...

249 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023472
2022934
202190
202092
2019104
2018101