Study of the phase-forming features in the ZrH2$z.sbnd;O2 system

Фокин, В. Н.; Malov, Yu. I.; Фокина, Э. Э.; Shilkin, S. P.

doi:10.1016/s0360-3199(96)00063-8

Cited by 13 publications

(6 citation statements)

References 1 publication

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“…It was found that the direct addition of oxygen to the hydride lattice not only varies the stoichiometry by stabilizing the oxygen positions in the crystal lattice, but also expands the possibilities of chemical control of the structural and electronic properties of such a modified metalÀhydride system. [4][5][6][7][8][9][10] The effect of partial oxidation makes the variation of the crystal structure stable, as chemical interactions form a reconfiguration of the valence charges that provides a new minimum of free energy. [3,10] Compared with the initial metal hydride, the ground state of the oxyhydride system exhibits better compositional and structural stability; its macroscopic mechanical properties are similar to those of complex crystalline oxides.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Design of Effective Multilayer Optical Coatings Using Oxyhydride Thin Films

Strugovshchikov

Pishtshev

Karazhanov

2021

Physica Status Solidi (b)

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Rare‐earth metal oxyhydride compositions are currently attracting increasing attention to develop materials with unusual optical responses. Herein, using computer simulations of the electronic and optical properties, the optical responses of two stable yttrium oxyhydride compounds, normalY4normalH10O and YHO, are studied for the visible light range. The emphasis is on modeling macroscopic optical characteristics, which are numerically derived within a conventional scheme using refractive indices, and absorption, transmittance, and reflection spectra. The main goal is twofold: first, to simulate spectral behavior of different single‐phase and two‐phase oxyhydride compositions and second, to conduct a comparative analysis that could explain the features of the transmission spectra measured for different samples. Based on the obtained results, models of new optical coatings are proposed in which yttrium oxyhydrides play the key role. In the context of nonlinear optics, the frequency profile of the second‐order susceptibility χ(2)(2ω) for the noncentrosymmetric cubic structure of normalY4normalH10O is evaluated and it is shown that this system could exhibit large optical nonlinearity.

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Section: Introductionmentioning

confidence: 99%

Theoretical Design of Effective Multilayer Optical Coatings Using Oxyhydride Thin Films

Strugovshchikov

Pishtshev

Karazhanov

2021

Physica Status Solidi (b)

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“…Over the past decade, the anion exchange of metal oxide for a hydride ion has become the subject of intensive research in the mixed-anion chemistry [6][7][8][9][10][11]. The original synthesis routes based on topotactic solid-state reactions and high-pressure methods were reported for a number of mixed-oxyanion crystalline phases with different levels of H -/O 2exchange [12][13][14][15][16][17][18][19][20][21][22]. Recently, investigations of the controllable oxidation of a metal-hydrogen mixture [23] have led to the synthesis of transition metal and rare-earth metal oxyhydride-type materials [24][25][26][27] which have demonstrated remarkable stability at room temperatures and atmospheric pressure.…”

Section: Introductionmentioning

confidence: 99%

On Prediction of a Novel Chiral Material Y2H3O(OH): A Hydroxyhydride Holding Hydridic and Protonic Hydrogens

2020

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Examination of possible pathways of how oxygen atoms can be added to a yttrium oxyhydride system allowed us to predict new derivatives such as hydroxyhydrides possessing the composition M2H3O(OH) (M = Y, Sc, La, and Gd) in which three different anions (H-, O2−, and OH-) share the common chemical space. The crystal data of the solid hydroxyhydrides obtained on the base of DFT modeling correspond to the tetragonal structure that is characterized by the chiral space group P 4 1 . The analysis of bonding situation in M2H3O(OH) showed that the microscopic mechanism governing chemical transformations is caused by the displacements of protons which are induced by interaction with oxygen atoms incorporated into the crystal lattice of the bulk oxyhydride. The oxygen-mediated transformation causes a change in the charge state of some adjacent hydridic sites, thus forming protonic sites associated with hydroxyl groups. The predicted materials demonstrate a specific charge ordering that is associated with the chiral structural organization of the metal cations and the anions because their lattice positions form helical curves spreading along the tetragonal axis. Moreover, the effect of spatial twisting of the H- and H+ sites provides additional linking via strong dihydrogen bonds. The structure–property relationships have been investigated in terms of structural, mechanical, electron, and optical features. It was shown that good polar properties of the materials make them possible prototypes for the design of nonlinear optical systems.

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“…Recently, there has been a significant interest in investigation of a series of mixed-anion inorganic compounds. 1,2 Classic examples are condensed oxyhydrides [3][4][5][6][7][8][9][10] and oxyfluorides; [11][12][13][14] they are of peculiar interest to the development of new generation of perspective functional materials. As it was reported in a number of the experimental and theoretical studies of bulk phases of yttrium oxyhydrides, [15][16][17][18][19] the anionic nature of these compounds is such that in the condensation process one can flexibly control structural, elastic and charge degrees of freedom by manipulating anion configurations in terms of O/H ratio.…”

Section: Introductionmentioning

confidence: 99%

Exploring The Anion Chemical Space: A Model of Electroelastic Material Ln2OF2-xClxH2 (Ln=Y,La,Gd) with High Mechanical Sensitivity and Remarkable Energy Harvesting

Strugovshchikov¹,

Pishtshev²

2020

Preprint

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The main result of our investigation is the prediction of a new family of multi-anion compounds - Ln2OF2-xClxH2 (Ln=Y,La,Gd) which due to anomalous elastic behaviour could present interest for the design and development of electromechanical devices. The composition Ln2OF2-xClxH2 utilizes complex heteroatomic anion [OF2-xClxH2]-6; in a solid state, as it follows from the DFT calculations, the system crystallizes into a columnar-type layered structure of P3m1 or R3m trigonal symmetries in which the LnO(F,Cl)H and Ln(F,Cl)FH layers are uniformly stacked in an alternating order along the high-symmetry c axis. In the trigonal lattice without inversion center, the resulting two-layers geometry puts groups of the anionic species together in a way that gives rise to the strong localization of valence charge density. We showed that being globally stable, such specific crystal architecture may lead to a high asymmetry of mechanical and electrical responses with respect to imposed loads. Moreover, small dynamic changes of the equilibrium charge and bonding configurations may cause rather the enhanced structural sensitivity of elastic responses at low pressures. Comparison of electromechanical characteristics showed that the predicted materials can serve as direct successors of the line of PVDF piezopolymers.

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Study of the phase-forming features in the ZrH2$z.sbnd;O2 system

Cited by 13 publications

References 1 publication

Theoretical Design of Effective Multilayer Optical Coatings Using Oxyhydride Thin Films

Theoretical Design of Effective Multilayer Optical Coatings Using Oxyhydride Thin Films

On Prediction of a Novel Chiral Material Y2H3O(OH): A Hydroxyhydride Holding Hydridic and Protonic Hydrogens

Exploring The Anion Chemical Space: A Model of Electroelastic Material Ln2OF2-xClxH2 (Ln=Y,La,Gd) with High Mechanical Sensitivity and Remarkable Energy Harvesting

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