Metal hydride single crystal

Detailed atomistic information of the elementary process of jump diffusion can be obtained from QENS at Q values comparable with the inverse jump distances, i.e. at large Q [14,28,29]. Hydrogen in the a-phases of the cubic f.c.c. and b.c.c. metals Pd, Nb, Ta and V was investigated very early, and the quite detailed results which are now available will be outlined first in Section 26.4.1. One of the rare cases where a hydride single crystal was available is y9-V2H, and the corresponding QENS study will be presented in some more detail in the second part of Section 26.4.1. 

The most important application of boron is to make fibers or whiskers of single crystal or ceramic crystal. The addition of boron to metals, alloys, or other solids, imparts resistance to plastic flow, and thereby produces unusual strength in the material. Amorphous boron is used in rockets as an igniter, and in pyrotechnic flares to give green color. Many boron compounds, such as borax, boron hydrides, and boron hahdes, have important commercial applications (see individual compounds). 

There are a great many examples of non-activated dissociation at surfaces. H2 dissociation on Pd(100) and the other single crystal faces of Pd are perhaps the best studied examples, both experimentally and theoretically. Part of the interest in these systems is the importance of Pd as a hydrogenation catalyst. The other major technological impetus is that bulk Pd readily absorbs large amounts of H, so is a prototype for metal-hydride hydrogen storage systems. 

Single crystals of transition-metal hydrides cannot be grown from the melt by the usual techniques because the hydrides dissociate at temperatures well below their melting points. The method used here is one of compound formation from saturated elemental melts. It is a modification of the technique used by Harman ct al.3 and Stambaugh et al.4 for growing crystals of III-V semiconducting compounds. 

M—H bond dissociation energies, 1, 287 photochemistry, 1, 251 single crystal neutron diffraction, 1, 578 stability toward disproportionation, 1, 301 Metal—hydrogen bonds bond dissociation energy in 1,2-dichloroethane, 1, 289 stable metal hydrides in acetonitrile, 1, 287 thermochemical cycle, 1, 286 in THF and dichloromethane, 1, 289 olefin insertion thermodynamics, 1, 629 in Zr(IV) bis-Cp complexes, 4, 878 Metal—hydrogen hydricity data, 1, 292... 

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