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Title: High-pressure single-crystal X-ray diffraction study of jadeite and kosmochlor

Authors:
; ; ; ;  [1];  [2];  [2];  [2]
  1. (Hawaii)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCESNSF
OSTI Identifier:
1162315
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Chem. Miner.; Journal Volume: 41; Journal Issue: (9) ; 10, 2014
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Posner, Esther S., Dera, Przemyslaw, Downs, Robert T., Lazarz, John D., Irmen, Peyton, UC), NWU), and Ariz). High-pressure single-crystal X-ray diffraction study of jadeite and kosmochlor. United States: N. p., 2016. Web. doi:10.1007/s00269-014-0684-y.
Posner, Esther S., Dera, Przemyslaw, Downs, Robert T., Lazarz, John D., Irmen, Peyton, UC), NWU), & Ariz). High-pressure single-crystal X-ray diffraction study of jadeite and kosmochlor. United States. doi:10.1007/s00269-014-0684-y.
Posner, Esther S., Dera, Przemyslaw, Downs, Robert T., Lazarz, John D., Irmen, Peyton, UC), NWU), and Ariz). 2016. "High-pressure single-crystal X-ray diffraction study of jadeite and kosmochlor". United States. doi:10.1007/s00269-014-0684-y.
@article{osti_1162315,
title = {High-pressure single-crystal X-ray diffraction study of jadeite and kosmochlor},
author = {Posner, Esther S. and Dera, Przemyslaw and Downs, Robert T. and Lazarz, John D. and Irmen, Peyton and UC) and NWU) and Ariz)},
abstractNote = {},
doi = {10.1007/s00269-014-0684-y},
journal = {Phys. Chem. Miner.},
number = (9) ; 10, 2014,
volume = 41,
place = {United States},
year = 2016,
month = 7
}
  • The first example of a pressure-induced Jahn-Teller distortion switch has been observed in a single-crystal time-of-flight neutron diffraction study of the Tutton salt (ND[sub 4])[sub 2][Cu(D[sub 2]O)[sub 6]](SO[sub 4])[sub 2] at T = 15 K, P = 1 bar (D[sub L]) and T = 15 K, P = 1.5 kbar (D[sub H]). Also studied was the hydrogenous salt (NH[sub 4])[sub 2][Cu(H[sub 2]O)[sub 6]](SO[sub 4])[sub 2] at T = 14 K, P = 1.4 kbar (H[sub H]). The unit cell parameters are as follows: D[sub L], a = 9.451(2) [angstrom], b = 12.736(3) [angstrom], c = 6.096(1) [angstrom], [beta] = 107.13(2)[degrees],more » Z = 2, V = 701.2(3) [angstrom][sup 3], space group = P2[sub 1]/a; D[sub H], a = 9.136(1) [angstrom], b = 12.285(2) [angstrom], c = 6.371(1) [angstrom], [beta] = 106.28(2)[degrees], Z = 2, V = 686.4(2) [angstrom][sup 3], space group = P2[sub 1]/a; H[sub H], a = 9.068(2) [angstrom], b = 12.232(2) [angstrom], c = 6.340(1) [angstrom], [beta] = 106.44(2), Z = 2, V = 674.5(2) [angstrom][sup 3], space group = P2[sub 1]/a. Application of 1.5 kbar of pressure to the deuterated crystal produces a decrease in the lengths of the a and b axes by 0.315(2) and 0.451(4) [angstrom], respectively, whereas the c axis increases by 0.275(1) [angstrom]. Comparison of the D[sub L] and D[sub H] structures shows that the long axis of the Jahn-Teller distortion has switched by 90[degrees], i.e., Cu(1)-O(7) = 2.022(2) and Cu(1)-O(8) = 2.310(2) [angstrom] for D[sub L] vs Cu(1)-O(7) = 2.290(2) and Cu(1)-O(8) = 2.014(2) [angstrom] for D[sub H], so that the D[sub H] and H[sub H] structures are similar. 38 refs., 6 figs., 3 tabs.« less
  • We report about the newly single crystal diffraction set-up development at ID30 beamline at the European Synchrotron Radiation Facility (ESRF). To illustrate the experimental performance of this set-up, we also present X-ray diffraction spectra recorded at high pressure (HP) using dedicated diamond anvil cell (DAC). Using this new setup, high quality synchrotron single crystal X-ray diffraction measurements of Pb2V3O9 have been performed at HP. We evidenced a reordering in the distorted system by resorbing the existing twin. The structure was partially solved by direct methods and refined by the use of the BRUKER suite of programs package.
  • The high-pressure phases of solid ammonia have been investigated by x-ray diffraction in a diamond anvil cell at room temperature. Despite the first-order solid phase transition at 4 GPa, quasi-single crystals of NH{sub 3} and ND{sub 3} could be obtained and compressed to 123 and 62 GPa, respectively. The observed reflections above 4 GPa are compatible with the structure determined by neutron diffraction on ND{sub 3}. We found strong evidence for an isosymmetric transition at 12 GPa in NH{sub 3} and 18 GPa in ND{sub 3}. This transition is more likely due to rearrangements of the hydrogen atoms, whereas themore » N atoms remain on their quasi-hcp sites. The experimental equation of state (EOS) is compared to the one derived from first-principles calculations. A stiffening of the EOS above 55 GPa could indicate the onset of a quantum-disordered regime for some of the H bonds.« less
  • We performed the single-crystal X-ray diffraction study of a perovskite-type gold mixed-valence compound, Cs{sub 2}Au{sup I}Au{sup III}Cl{sub 6}, under high pressures up to 18 GPa by using a diamond-anvil-cell with helium gas as an ideal hydrostatic pressure-transmitting medium. The lattice parameters and the variable atomic positional parameters were obtained with reasonable accuracy at various pressures. A structural phase transition at ca. 12.5 GPa from I4/mmm to Pm3m was found. The lattice parameters a {sub 0} and c {sub 0}, denoted in the tetragonal cell setting, result in the relationship 2{sup 1/2} a {sub 0}=c {sub 0}, and the superstructure reflectionsmore » h k l (l is odd), caused by the shift of the Cl ions from the midpoint of the Au ions, disappeared at pressures above the phase transition. Both elongated [Au{sup III}Cl{sub 6}] and compressed [Au{sup I}Cl{sub 6}] octahedra in the low-pressure phase smoothly approach regular octahedra with increasing pressure. Above the structural phase transition at 12.5 GPa, all the [AuCl{sub 6}] octahedra are crystallographically equivalent, which shows that the tetragonal-to-cubic phase transition accompanies the valence transition from the Au{sup I}/Au{sup III} mixed-valence state to the Au{sup II} single-valence state. - Graphical abstract: Single-crystal X-ray diffraction study under high pressures up to 18 GPa by using a diamond-anvil-cell with helium gas as an ideal hydrostatic pressure medium has revealed that a perovskite-type gold mixed-valence compound, Cs{sub 2}Au{sup I}Au{sup III}Cl{sub 6}, exhibits the structural phase transition from tetragonal to cubic at 12.5 GPa accompanying gold valence transition.« less
  • The crystal structure of a natural coesite from an eclogite rock fragment in the Roberts Victor kimberlite, South Africa, was determined at 15 K by neutron diffraction (a = 7.1357 (13) A, b = 12.3835 (26) A, c = 7.1859 (11) A, ..beta.. = 120.375 (16)/sup 0/, C2/c), and at approx.298 K by X-ray diffraction. Cell dimensions measured by neutron diffraction at 292 K (7.1464 (9), 12.3796 (19), and 7.1829 (8) A, 120.283 (9)/sup 0/) differed from those determined by X-ray diffraction, probably because of a systematic absorption error for the latter. The strongly anisotropic nature of the thermal expansionmore » is explained qualitatively by the relatively large changes (approx.1%) in the distances between the nonbonded oxygen neighbors and the relatively small changes of Si-O-Si and O-Si-O angles in the compact three-dimensional framework. There is a good, but not perfect, negative correlation between the eight independent Si-O distances and the five independent values for sec theta(Si-O-Si) at 15 K. It is weaker than that for 298 K, and the scatter from a straight-line prediction from molecular-orbital models for small clusters (e.g., H/sub 6/Si/sub 2/O/sub 7/) implies that it is desirably to consider additional forces, including repulsive forces between nonbonded oxygen neighbors. The combined at a for Si-O and Si-O-Si in coesite, quartz, and cristobalite at 10-15 K show less scatter than those for approx.298 K, in accordance with the greater thermal response of framework geometry in the more open structures.« less