Search results for "alkaline earth"
showing 10 items of 31 documents
First principles hybrid Hartree-Fock-DFT calculations of bulk and (001) surface F centers in oxide perovskites and alkaline-earth fluorides
2020
Valuable discussions with E. A. Kotomin are gratefully acknowledged. Research contribution of R. E. and A. I. P. has been performed within the framework of the EUROfusion Enabling Research project: ENR-MFE19.ISSP-UL-02 “Advanced experimental and theoretical analysis of defect evolution and structural disordering in optical and dielectric materials for fusion applications.” The views and opinions expressed herein do not necessarily reflect those of the European Commission.
ChemInform Abstract: Mercaptophenol-Protected Gold Colloides as Nuclei for the Crystallization of Inorganic Minerals: Templated Crystallization on Cu…
2010
The transport of ions across monoolein bilayers mediated by synthetic macrocyclic carriers
1989
The efficiency as carriers for the alkali and the alkaline earth ions across monoolein bilayers of three macrocyclic compounds has been investigated by conductometric measurements. The results show that although the three compounds have the optimum cavity size for fitting potassium and barium cations, their efficiency in ionic transport is quite different. These discrepancies are rationalized on the basis of the overlap of the water-diazacrown and cation-ligand interactions on the carrier mechanism.
Caracterización de barita cubana y su reducción carbotérmica en horno de microondas
2007
The Cuban Barite (BaSO4) is characterized by X ray diffraction, chemical analysis and scanning electron microscopy. The principal components are identified and its characteristic morphology is shown. Its carbothermic reduction under microwave irradiation is carried out with the purpose of to improve the yield of this stage during the mineral transformation process in reagent of barium of diverse applications. La barita cubana (BaSO4) se ha caracterizado por difracción de rayos X, análisis químico y microscopía electrónica de barrido. Se han identificado sus componentes mayoritarios y así mismo se muestra su morfología característica. Se ha realizado su reducción carbotérmica en horno de mic…
Homoleptic heavy alkaline Earth and europium triazenides.
2009
The sigma-bond metathesis reaction between PhSiH(3) and the heteroleptic metal pentafluorophenyl compounds [Dmp(Tph)N(3)MC(6)F(5)(thf)(n)] (Dmp = 2,6-Mes(2)C(6)H(3) with Mes = 2,4,6-Me(3)C(6)H(2); Tph = 2-TripC(6)H(4) with Trip = 2,4,6-(i)Pr(3)C(6)H(2); n = 1, 2; M = Sr, Ba, Eu) supported by sterically crowded, biphenyl- and terphenyl-substituented triazenido ligands afforded the first homoleptic stontium, barium, and europium triazenides [M{N(3)Dmp(Tph)}(2)] {M = Sr (2), Ba (4), Eu (5)}. Crystallization of 2 from an n-heptane/1,2-dimethoxyethane mixture gave the complex [Sr{N(3)Dmp(Tph)}(2)(dme)] (3). All new compounds have been characterized by (1)H and (13)C NMR spectroscopy (not 5), ele…
Interactions of Ultra-cold Alkaline-earth-like and Alkali Atoms with Light
2019
This paper presents the experimental results of photoionization and photoassociation experiments performed with both ultra-cold alkaline-earth-like and alkali atoms. Photoionization cross-section was studied for 88Sr at the blue magic 390 nm wavelength as well as for 87Rb at 254 nm. We also present preliminary results of photoassociation spectroscopy of the molecular line detected near the dissociation threshold of the excited Rb*Hg molecule at D1 Rb line (795 nm).
High-Pressure Phase Diagram and Superionicity of Alkaline Earth Metal Difluorides
2018
We study the high-pressure–high-temperature phase diagram and superionicity of alkaline earth metal (AEM) difluorides (AF2, A = Ca, Sr, Ba) with first-principles simulation methods. We find that the superionic behavior of SrF2 and BaF2 at high pressures differ appreciably from that previously reported for CaF2 [Phys. Rev. Lett. 2014, 113, 235902]. Specifically, the critical superionic temperature of SrF2 and BaF2 in the low-pressure cubic fluorite phase is not reduced by effect of compression, and the corresponding high-pressure orthorhombic contunnite phases become superionic at elevated temperatures. We get valuable microscopic insights into the superionic features of AEM difluorides in b…
Observation of chemical reactions between alkaline-earth oxides and tungsten at high pressure and high temperature
2009
Abstract The potential chemical reactions of alkaline-earth oxides (AeO with Ae: Mg, Ca, Sr, and Ba) and tungsten are studied at high pressure and high temperature. At pressures ranging from 5 to 10 GPa and temperatures of 2000 K, a noticeable reaction between AeO and powder tungsten (W) was detected. As a product of the reaction, scheelite-structured orthotungstates (AeWO 4 ) were formed. The reactivity of alkaline-earth oxides with tungsten increases in the order Ca 2 →AeWO 4 .
Redox-active crown ethers derived from biphenyl. Electrochemical and spectroscopic study of binding processes with alkali, alkali-earth and mercury s…
1998
Abstract Three new electroactive ligands, 3a, 3b and 3c, that contain the biphenyl frameworks in their structure were prepared. These new ligands presented three interesting characteristics: 1) they exhibited a reversible oxidation, 2) the oxidation induced a conformational change in the crown moiety and 3) they had two different coordination centers, the crown ether and the dimethylamino groups. Electrochemical and spectroscopic studies using alkali, alkali-earth and mercury salts were carried out.