Structure of the high pressure phase γ-MgH2 by neutron powder diffraction

Bortz, M.; Bertheville, B.; Böttger, G.; Yvon, K.

doi:10.1016/s0925-8388(99)00028-6

Cited by 245 publications

(167 citation statements)

References 4 publications

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“…[50][51][52] Magnesium hydride, whose crystal structure is simple tetragonal, is a highly stable hydride with strong Mg-H bond, which is a mixture of ionic and covalent bonding. 53 The calculated bulk lattice constants are a MgH2 = b MgH2 = 4.452 Å, c MgH2 = 2.992 Å with the c/a value of 0.672, which agree well with the previous experimental [54][55][56] and theoretical [57][58][59] results.…”

Section: A the Bulk Properties Of Magnesium And Magnesium Hydridesupporting

confidence: 87%

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

et al. 2014

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We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg($10\bar 10$101¯0)/MgH2(210), Mg(0001)/MgH2(101) and Mg($10\bar 10$101¯0)/MgH2(101), and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001)/MgH2(101) which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

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Section: A the Bulk Properties Of Magnesium And Magnesium Hydridesupporting

confidence: 87%

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

et al. 2014

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“…It should also be noted that Bortz et al investigated the crystal structure of γ-MgH 2 from powder neutron-diffraction data collected at 2 GPa. 30 This highpressure γ modification is maintained as the metastable phase when the pressure is released at room temperature after a completed pressure loading−unloading cycle. Many density functional theory (DFT) studies have attempted to predict the effect of pressure on the phase transitions for the polymorphs of MgH 2 , but no general agreement on the results was obtained.…”

Section: Computational Detailsmentioning

confidence: 99%

Influence of Crystal Structure of Bulk Phase on the Stability of Nanoscale Phases: Investigation on MgH₂ Derived Nanostructures

Vajeeston¹,

Ravindran

Fichtner

et al. 2012

J. Phys. Chem. C

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Phase stability of α-, β-, γ-, and δ′-MgH 2 -derived nanostructures have been investigated using ab initio projected augmented plane wave method. Structural optimizations based on total energy calculations predicted that β-derived nanoparticles and α-derived nanowhiskers are more stable than those derived from other polymorphs. Present study indicates that the crystal structure of the bulk phase plays a significant role on the stabilization of different forms (nanoparticles or nanowhiskers) of nanophases. The predicted critical sizes of the stable β-nanoparticle and α-nanowhisker for MgH 2 are 2.4 and 1.5 nm, respectively. The calculated hydrogen site energies suggest that it is relatively easier to remove hydrogen from the surface of the nanoparticles and nanowhiskers compared to that from bulk crystals. Among the considered nano-objects, removing hydrogen from the β-derived nanocluster is much easier, and hence, the present study suggests that one can use these nanoparticles for practical applications. NMR-related parameters are calculated for different sizes of the nanoclusters and nanowhiskers.

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“…This is in good agreement with the experimental values a = 4.50 Å, c = 3.01 Å, and x = 0.304. 68 The magnesium atoms are sixfold octahedrally coordinated by the hydrogen atoms at distances between 1.94 and 1.96 Å. Each MgH 6 octahedron shares the hydrogen atoms at its corners with neighboring octahedra.…”

Section: Mghmentioning

confidence: 99%

Electronic structure and optical properties of lightweight metal hydrides

et al. 2007

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, using first-principles densityfunctional theory and GW calculations. All compounds are large gap insulators with GW single-particle band gaps varying from 3.5 eV in AlH 3 to 6.6 eV in LiAlH 4 . Despite considerable differences between the band structures and the band gaps of the various compounds, their optical responses are qualitatively similar. In most of the spectra the optical absorption rises sharply above 6 eV and has a strong peak around 8 eV. The quantitative differences in the optical spectra are interpreted in terms of the structure and the electronic structure of the compounds. In the simple hydrides the valence bands are dominated by the hydrogen atoms, whereas the conduction bands have mixed contributions from the hydrogens and the metal cations. The electronic structure of the aluminium compounds is determined mainly by aluminium hydride complexes and their mutual interactions.

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Structure of the high pressure phase γ-MgH2 by neutron powder diffraction

Cited by 245 publications

References 4 publications

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

Influence of Crystal Structure of Bulk Phase on the Stability of Nanoscale Phases: Investigation on MgH₂ Derived Nanostructures

Electronic structure and optical properties of lightweight metal hydrides

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Structure of the high pressure phase γ-MgH2 by neutron powder diffraction

Cited by 245 publications

References 4 publications

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

Influence of Crystal Structure of Bulk Phase on the Stability of Nanoscale Phases: Investigation on MgH2 Derived Nanostructures

Electronic structure and optical properties of lightweight metal hydrides

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Influence of Crystal Structure of Bulk Phase on the Stability of Nanoscale Phases: Investigation on MgH₂ Derived Nanostructures