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Valence (chemistry)

About: Valence (chemistry) is a research topic. Over the lifetime, 24937 publications have been published within this topic receiving 645252 citations. The topic is also known as: valency.


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Journal ArticleDOI
TL;DR: In this article, the experimental radii for all d and f transition metals are given, and the set of radii refers to twelve coordination and is based on the observed atomic volumes of the metals.

111 citations

Journal ArticleDOI
10 Jan 2020-Science
TL;DR: T tunable femtosecond soft x-ray pulses from an x-rays free electron laser are used to reveal the dynamics of the valence hole created by strong-field ionization and to track the primary proton transfer reaction giving rise to the formation of OH.
Abstract: Elementary processes associated with ionization of liquid water provide a framework for understanding radiation-matter interactions in chemistry and biology. Although numerous studies have been conducted on the dynamics of the hydrated electron, its partner arising from ionization of liquid water, H2O+, remains elusive. We used tunable femtosecond soft x-ray pulses from an x-ray free electron laser to reveal the dynamics of the valence hole created by strong-field ionization and to track the primary proton transfer reaction giving rise to the formation of OH. The isolated resonance associated with the valence hole (H2O+/OH) enabled straightforward detection. Molecular dynamics simulations revealed that the x-ray spectra are sensitive to structural dynamics at the ionization site. We found signatures of hydrated-electron dynamics in the x-ray spectrum.

111 citations

Journal ArticleDOI
TL;DR: In this paper, the spectral function of ionization is discussed for the whole energy range, and it is found that different energy regions are likely to exhibit different types of many-body effects.
Abstract: The spectral function of ionization is discussed for the whole energy range. It is found that different energy regions are likely to exhibit different types of many-body effects. For the ionization out of an outer valence orbital most of the intensity appears in one main line. The many-body effects explain the additional satellite lines and, in addition, can lead to an ordering of main lines which is different from the ordering determined from one-particle calculations. For the ionization out of an inner valence orbital the intensity may be distributed over several lines and in many cases it is not possible to identify any of these lines as the main line representing the orbital. Such a breakdown of the quasiparticle picture of ionization is stressed to be a common phenomenon. Ionization of core orbitals can usually be viewed within a quasiparticle picture, i.e., the process leads to a main line accompanied by satellite lines. In cases, however, where the creation of the core hole leads to a strong charge transfer, the shake-up energies can become small or even negative and the quasiparticle picture may break down. The origin of the above effects is discussed and typical examples are presented.

111 citations

Journal ArticleDOI
TL;DR: In this paper, the x-ray absorption near-edge structure (XANES) spectra of a selection of silicate and aluminosilicate minerals have been measured using synchrotron radiation (SR).
Abstract: Silicon K-edge x-ray absorption near-edge structure (XANES) spectra of a selection of silicate and aluminosilicate minerals have been measured using synchrotron radiation (SR). The spectra are qualitatively interpreted based on MO calculation of the tetrahedral SiO44−cluster. The Si K-edge generally shifts to higher energy with increased polymerization of silicates by about 1.3 eV, but with considerable overlap for silicates of different polymerization types. The substitution of Al for Si shifts the Si K-edge to lower energy. The chemical shift of Si K-edge is also sensitive to cations in more distant atom shells; for example, the Si K-edge shifts to lower energy with the substitution of Al for Mg in octahedral sites. The shifts of the Si K-edge show weak correlation with average Si-O bond distance (dSi-O), Si-O bond valence (sSi-O) and distortion of SiO4 tetrahedra, due to the crystal structure complexity of silicate minerals and multiple factors effecting the x-ray absorption processes.

110 citations

Journal ArticleDOI
TL;DR: The first mixed-valence coordination polymer indicating ferroelectric properties, {[CuI4CuII(Et2dtc)2Cl3]2(FeCl4)}n (Et 2dtc- = diethyldithiocarbamate), has been synthesized and crystallographically characterized.
Abstract: The first mixed-valence coordination polymer indicating ferroelectric properties, {[CuI4CuII(Et2dtc)2Cl3][CuII(Et2dtc)2]2(FeCl4)}n (Et2dtc- = diethyldithiocarbamate), has been synthesized and crystallographically characterized. This complex has a two-dimensional infinite square lattice structure, including both Cu(I) and Cu(II) ions, which is confirmed by XPS and SQUID measurements. In addition, the ferroelectric behaviors are revealed by the dielectric measurements with a LCR meter and a ferroelectric tester.

110 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,521
20222,997
2021616
2020611
2019584
2018577