			Home About us Contact

Metal Hydrides (metal + hydride)

Distribution by Scientific Domains

Chemistry	75%
Polymers and Materials Science	16%

Kinds of Metal Hydrides

transition metal hydride

Selected Abstracts

Volume Chemistry of Hydrogen in Binary and Ternary Metal Hydrides.

CHEMINFORM, Issue 16 2005
Welf Bronger
No abstract is available for this article. [source]

Regioselective Reduction of 5-Substituted 2-Alkylidene-4-oxothiazolidines by Metal Hydrides.

CHEMINFORM, Issue 38 2004
Rade Markovic
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Dissociation Potential Curves of Low-Lying States in Transition Metal Hydrides.

CHEMINFORM, Issue 31 2004
Part 2.
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Strategies for the Improvement of the Hydrogen Storage Properties of Metal Hydride Materials

CHEMPHYSCHEM, Issue 15 2008
Hui Wu
Abstract Metal hydrides are an important family of materials that can potentially be used for safe, efficient and reversible on-board hydrogen storage. Light-weight metal hydrides in particular have attracted intense interest due to their high hydrogen density. However, most of these hydrides have rather slow absorption kinetics, relatively high thermal stability, and/or problems with the reversibility of hydrogen absorption/desorption cycling. This paper discusses a number of different approaches for the improvement of the hydrogen storage properties of these materials, with emphasis on recent research on tuning the ionic mobility in mixed hydrides. This concept opens a promising pathway to accelerate hydrogenation kinetics, reduce the activation energy for hydrogen release, and minimize deleterious possible by-products often associated with complex hydride systems. [source]

Enhancement of heat transfer in hydrogen storage tank with hydrogen absorbing alloy (optimum fin layout)

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 3 2008
Yuichi Mitsutake
Abstract Optimization of the fin layout in a metal hydride (MH) bed has been sought to enhance poor heat transmission in a hydrogen storage tank, and to obtain a maximum hydrogen absorption rate with a smaller volume of fins. Two different fin configurations, radial and circular fins, in a vertical cylindrical reactor vessel were tested with a La-Ni-based AB5 type hydrogen storage alloy. A two-dimensional transient heat conduction analysis, coupled with predicted temperature and concentration of absorbed hydrogen in the bed for the exothermic hydride reaction, was used to evaluate enhancement of the hydrogen absorption time. The estimated temperature and concentration agreed within 6 K and 8.5%, respectively, with our experimental results. The effect of thickness and the spacing and shape of fins on the hydrogen absorption time were analytically evaluated, so that the optimum range of the each fin layout was obtained by the trade off between absorption time and reduction in the MH volume due to the volume occupied by fins. The hydrogen absorption time for the recommended layout of circular fins was reduced to approximately one-third of that without fins. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(3): 165,183, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20195 [source]

Hydrogen/Deuterium Exchange Reactions of Olefins with Deuterium Oxide Mediated by the Carbonylchlorohydrido- tris(triphenylphosphine)ruthenium(II) Complex

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010
Sunny Kai San Tse
Abstract The catalytic properties of several ruthenium, osmium and rhodium hydride complexes for hydrogen/deuterium (H/D) exchange between olefins and deuterium oxide (D2O) were investigated. The most effective catalytic precursor was found to be the carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) complex. Through H/D exchange between metal hydride and D2O, and reversible olefin insertion into an RuH(D) bond, protons attached to olefinic carbons and alkyl chains of olefins can all undergo H/D exchange with D2O. The catalytic reactions can be used to deuterate both terminal and internal olefins, for example, styrene, stilbene and cyclooctene. [source]

Solid-State Structures and Properties of Europium and Samarium Hydrides

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2010
Holger Kohlmann
Abstract The structural chemistry of europium and samarium hydrides in the solid state is very rich, ranging from typical ionic hydrides following the hydride-fluoride analogy to complex transition metal hydrides and interstitial hydrides. While crystal structure, electrical, and magnetic properties suggest that europium is divalent in all hydrides investigated so far, samarium is easily transformed to a trivalent oxidation state in its hydrides and shows similarities to other lanthanide(III) hydrides. The problem of neutron absorption of europium and samarium, hampering crystal structure solution and limiting the available structural information, is discussed in detail, and practical solutions for neutron diffraction experiments are given. [source]

Tailoring Hydrogen Storage Materials Towards Application

ADVANCED ENGINEERING MATERIALS, Issue 5 2006
M. Dornheim
Abstract A breakthrough in hydrogen storage technology was achieved by preparing nanocrystalline hydrides using high-energy ball milling and the use of suitable catalysts/additives. These new materials show fast or in case of Mg-based hydrides very fast absorption and desorption kinetics within minutes, thus qualifying lightweight Mg- or Al-based hydrides for storage applications. This article summarizes our current understanding of the kinetics of Mg-based light metal hydrides, describes an approach for a cost-effective processing technology and highlights some promising new developments in lightweight metal hydride research. [source]

Exploiting the Kubas Interaction in the Design of Hydrogen Storage Materials

ADVANCED MATERIALS, Issue 18 2009
Tuan K. A. Hoang
Abstract Hydrogen adsorption and storage using solid-state materials is an area of much current research interest, and one of the major stumbling blocks in realizing the hydrogen economy. However, no material yet researched comes close to reaching the DOE 2015 targets of 9,wt% and 80,kg,m,3 at this time. To increase the physisorption capacities of these materials, the heats of adsorption must be increased to ,20,kJ,mol,1. This can be accomplished by optimizing the material structure, creating more active species on the surface, or improving the interaction of the surface with hydrogen. The main focus of this progress report are recent advances in physisorption materials exhibiting higher heats of adsorption and better hydrogen adsorption at room temperature based on exploiting the Kubas model for hydrogen binding: (,2 -H2),metal interaction. Both computational approaches and synthetic achievements will be discussed. Materials exploiting the Kubas interaction represent a median on the continuum between metal hydrides and physisorption materials, and are becoming increasingly important as researchers learn more about their applications to hydrogen storage problems. [source]

Photochemistry of CH3Mn(CO)5: A multiconfigurational ab initio study

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2006
Leticia González
Abstract The electronic spectroscopy of CH3Mn(CO)5 has been investigated by means of ab initio multiconfigurational MS-CASPT2/CASSCF calculations. The absorption spectrum is characterized by a series of Metal-Centered (MC) excited states in the UV energy domain (below 290 nm) that could be responsible for the observed photoreactivity starting at 308 nm. The upper part of the spectrum is overcrowded between 264 and 206 nm and dominated by a high density of Metal-to-Ligand-Charge-Transfer (MLCT) states corresponding mainly to 3dMn , ,*CO excitations. A non-negligible contribution of Metal-to-,-Bond-Charge-Transfer (MSBCT) states corresponding to 3dMn , ,*Mn-CH3 excitations is also present in the theoretical spectrum of CH3Mn(CO)5. However, in contrast to other transition metal hydrides and methyl substituted (HMn(CO)5, HCo(CO)4, and CH3Co(CO)4) these MSBCT transitions do not participate to the lowest bands of the spectrum as main contributions. The photochemistry of CH3Mn(CO)5, namely the loss of a CO ligand vs. the metal-methyl bond homolysis, is investigated by means of MS-CASPT2 states correlation diagrams. This study illustrates the complexity of the photodissociation mechanism of this class of molecules, which involves a large number of nearly degenerate electronic states with several channels for fragmentation. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006 [source]

Bond lengths in organic and metal-organic compounds revisited: X,H bond lengths from neutron diffraction data

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2010
Frank H. Allen
The number of structures in the Cambridge Structural Database (CSD) has increased by an order of magnitude since the preparation of two major compilations of standard bond lengths in mid-1985. It is now of interest to examine whether this huge increase in data availability has implications for the mean bond-length values published in the late 1980s. Those compilations reported mean X,H bond lengths derived from rather sparse information and for rather few chemical environments. During the intervening years, the number of neutron studies has also increased, although only by a factor of around 2.25, permitting a new analysis of X,H bond-length distributions for (a) organic X = C, N, O, B, and (b) a variety of terminal and homometallic bridging transition metal hydrides. New mean values are reported here and are compared with earlier results. These new overall means are also complemented by an analysis of X,H distances at lower temperatures (T, 140,K), which indicates the general level of librational effects in X,H systems. The study also extends the range of chemical environments for which statistically acceptable mean X,H bond lengths can be obtained, although values from individual structures are also collated to further extend the chemical range of this compilation. Updated default `neutron-normalization' distances for use in hydrogen-bond and deformation-density studies are also proposed for C,H, N,H and O,H, and the low-temperature analysis provides specific values for certain chemical environments and hybridization states of X. [source]