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Title: Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2)

Authors:
 [1];  [1];  [1]
  1. Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NSFDHS - DEPARTMENT OF HOMELAND SECURITY
OSTI Identifier:
1314243
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 145; Journal Issue: 8
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Dunuwille, Mihindra, Kim, Minseob, and Yoo, Choong-Shik. Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2). United States: N. p., 2016. Web. doi:10.1063/1.4961453.
Dunuwille, Mihindra, Kim, Minseob, & Yoo, Choong-Shik. Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2). United States. doi:10.1063/1.4961453.
Dunuwille, Mihindra, Kim, Minseob, and Yoo, Choong-Shik. Wed . "Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2)". United States. doi:10.1063/1.4961453.
@article{osti_1314243,
title = {Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2)},
author = {Dunuwille, Mihindra and Kim, Minseob and Yoo, Choong-Shik},
abstractNote = {},
doi = {10.1063/1.4961453},
journal = {Journal of Chemical Physics},
number = 8,
volume = 145,
place = {United States},
year = {Wed Aug 24 00:00:00 EDT 2016},
month = {Wed Aug 24 00:00:00 EDT 2016}
}
  • {ital In} {ital situ} high-pressure x-ray-diffraction studies have been carried out on TlReO{sub 4} up to 14.5 GPa at room temperature using a diamond-anvil cell. The x-ray data show that the orthorhombic {ital D}{sub 2{ital h}}{sup 16} TlReO{sub 4} (I) transforms to another closely related orthorhombic phase, TlReO{sub 4} (I{prime}) around 1.0 GPa, then to a wolframite-related monoclinic phase TlReO{sub 4} (II) near 2.0 GPa, and finally to a BaWO{sub 4} (II)-related monoclinic phase TlReO{sub 4} (III) at about 10 GPa. The volume change at the first transition is negligible, and about 2% and 9%, respectively, at the two subsequentmore » transitions. The results suggest a very minor change in structure at the first transition. The 2% {Delta}{ital V} at the second transition is consistent with the proposed structural arrangement from pseudoscheelite phase (I{prime}) to the wolframite phase (II). The large {Delta}{ital V} at the third transition is attributed to a change to a truly octahedral coordination for Re with respect to oxygens. All the three high-pressure phases of TlReO{sub 4} are unquenchable and revert back to the low-pressure orthorhombic phase (I) on release of pressure. The results are in very good agreement with those obtained in a previous high-pressure Raman study up to 15 GPa. From pressure-volume data, we obtain a value of 26 GPa for the bulk modulus {ital K}{sub 0} of phases (I) and (I{prime}). The bulk moduli of phases (II) and (III) have been calculated as 45.6 and 47.6 GPa, respectively.« less
  • Among the bcc alkali metals, lithium and sodium show a deformation behavior very different from potassium, which in turn behaves similar to the bcc transition metals. Li as well as Na show a moderate temperature dependence of the yield stress below critical temperatures of 0.5 T[sub m] (Li) and 0.4 T[sub m] (Na), respectively. This temperature range is too high for an intrinsic lattice mechanism (such as for instance kink-pair formation) to be the rate-controlling process. The activation volumes also take very high values of 3000-20000 b[sup 3]. Therefore Kircher suggested a model of dislocation forest cutting. On the othermore » hand, the experiments showed an orientation dependence of the critical resolved shear stress and an asymmetry between tension and compression. Such a behavior seems to be in contrast to a mechanism of forest interaction. This discrepancy has never been clarified, an up to now there is no model which could consistently explain the observed deformation properties of lithium and sodium. In the present work tensile tests of high purity lithium single crystals were performed in the range between 300 K and 100 K. In contrast to the previous experiments the crystals were in-situ annealed in the cryostat between each deformation step in order to restore the original dislocation structure. This technique is facilitated very much by the low melting point of lithium, which recovers very rapidly at room temperature corresponding to 0.65 T[sub m].« less
  • Tsuneyuki [ital et] [ital al]. predicted a new high pressure phase of silica using a molecular dynamics calculation; this calculation was novel in that it predicted a new crystal structure using only a knowledge of the chemical composition [Nature (London) 339, 209 (1989)]. We report that the low-cristobalite phase of GaPO[sub 4] undergoes a pressure-induced transition at 15.91 GPa to this novel phase, which contains tetrahedral and octahedral coordination shells of oxygen atoms around the phosphorus and gallium atoms, respectively. This pressure-induced coordination change in GaPO[sub 4] verifies a mechanism proposed for the tetrahedral-to-octahedral coordination change in minerals that occursmore » in the transition zone between the upper and lower mantle.« less
  • A drastic suppression of the chain post polymerization process in the quenched high-pressure phase of an acrylamide-water eutectic mixture was observed upon warming of the samples irradiated with {gamma}-rays at 77 K. This effect is explained by dispersion of the samples in the temperature region of the transition of the quenched high-pressure phase into the equilibrium phase ({approximately}150K). The size of the resulting microcrystals of monomer was estimated to be approximately 0.1 {mu}m.