The study of the structure stability of hexagonal Bi(PO4)(H2O)0.67 under high pressure

2017 ◽  
Vol 31 (25) ◽  
pp. 1745020 ◽  
Author(s):  
Jun Zhang ◽  
Zhen Yuan ◽  
Jian-Fa Zhao ◽  
Wen-Min Li ◽  
Ya-Ting Jia ◽  
...  
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Unit Cell Volume ◽  
Ambient Pressure ◽  
Structure Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Experimental Pressure ◽  
Text Unit

In this work, the structure stability of hexagonal Bi(PO[Formula: see text](H2O)[Formula: see text] has been investigated by high-pressure synchrotron X-ray diffraction measurements. The results show that the structure is stable within the pressure up to 18.3 GPa. The diffraction data are refined and the lattice constants [Formula: see text] and [Formula: see text] are determined, which is compressed by 6.3(7)% and 3.5(0)% within the experimental pressure, respectively. By fitting the pressure dependence of [Formula: see text] (unit cell volume divided by that at ambient pressure) with the second-order Birch equation of state, the bulk modulus [Formula: see text] is given to be about 87.1(0) GPa.

scholarly journals High-Pressure Structural Behavior and Equation of State of Kagome Staircase Compound, Ni3V2O8

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 910
Author(s):  
Daniel Diaz-Anichtchenko ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Simone Anzellini ◽  
Daniel Errandonea
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
A Chain

We report on high-pressure synchrotron X-ray diffraction measurements on Ni3V2O8 at room-temperature up to 23 GPa. According to this study, the ambient-pressure orthorhombic structure remains stable up to the highest pressure reached in the experiments. We have also obtained the pressure dependence of the unit-cell parameters, which reveals an anisotropic compression behavior. In addition, a room-temperature pressure–volume third-order Birch–Murnaghan equation of state has been obtained with parameters: V0 = 555.7(2) Å3, K0 = 139(3) GPa, and K0′ = 4.4(3). According to this result, Ni3V2O8 is the least compressible kagome-type vanadate. The changes of the crystal structure under compression have been related to the presence of a chain of edge-sharing NiO6 octahedral units forming kagome staircases interconnected by VO4 rigid tetrahedral units. The reported results are discussed in comparison with high-pressure X-ray diffraction results from isostructural Zn3V2O8 and density-functional theory calculations on several isostructural vanadates.

X-Ray Structural Study of Li3N at High Pressure

1997 ◽  
Vol 499 ◽  
Author(s):  
Allen C. Ho ◽  
Maurice K. Granger ◽  
Arthur L. Ruoff
Keyword(s):  
High Pressure ◽  
Free Energy ◽  
Synchrotron Radiation ◽  
Equation Of State ◽  
Ambient Temperature ◽  
Structural Study ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gibb’S Free Energy

ABSTRACTThe equation of state (EOS) of Li3N has been determined by energy-dispersive x-ray diffraction (EDXD) using synchrotron radiation up to 35 GPa at ambient temperature. Both the hexagonal D6h4(P63/mmc) and the hexagonal D6h1(P6/mmm) phases were present at ambient pressure. The D6h1 -structure completely transforms into the D6h4 -structure at modest pressure. The change in Gibb's free energy as a function of pressure for Li3N was calculated using the experimental EOS.

Synthesis and structure stability of Ba2CuO3+δ under high pressure

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542024 ◽  
Author(s):  
W. M. Li ◽  
Q. Q. Liu ◽  
Y. Liu ◽  
S. M. Feng ◽  
X. C. Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Equation Of State ◽  
Room Temperature ◽  
Text Structure ◽  
Structure Stability ◽  
Nominal Composition ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray

The [Formula: see text] sample with the nominal composition was synthesized. Powder X-ray diffraction (XRD) experiments confirm that it crystallizes in an orthorhombic structure with space group Immm. The synchrotron powder XRD results suggest that the crystal structure of [Formula: see text] keeps stable under pressure up to 34 GPa at room temperature with nearly isotropic compressibility. The equation of state for [Formula: see text] was obtained. The results offer opportunities to further synthesize and research [Formula: see text] superconductor with tetragonal [Formula: see text] structure.

FexCu1-xBa2YCu2O7+y SUPERCONDUCTORS SYNTHESIZED BY HIGH PRESSURE

2005 ◽  
Vol 19 (01n03) ◽  
pp. 221-223 ◽  
Author(s):  
Y. H. LIU ◽  
G. C. CHE ◽  
K. Q. LI ◽  
Z. X. ZHAO ◽  
Z. Q. KOU ◽  
...  
Keyword(s):  
High Pressure ◽  
Cell Volume ◽  
Oxygen Content ◽  
Unit Cell Volume ◽  
Ambient Pressure ◽  
Lattice Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Coordination

Systematic studies of x-ray diffraction(XRD), superconductivity and Mössbauer effect on Fe x Cu 1-x Ba 2 YCu 2 O 7+y ( x =0.00~0.70) superconductors synthesized by high pressure (HP) were summarized. All the HP-samples have tetragonal structure, smaller lattice parameter c and unit-cell volume than the AM-samples (synthesized by ambient pressure). The HP-samples have higher oxygen content than the AM-samples. Moreover, for the HP-sample with x =0.5, all of the Fe located in the CuO x chains have fivefold-oxygen coordination.

XRPD and Scanning Electron Microscopy of Alloys of the CuAlS2 – CuFeS2 System Prepared by Thermobaric Treatment

MRS Advances ◽  
2018 ◽  
Vol 3 (56) ◽  
pp. 3323-3328
Author(s):  
Barys Korzun ◽  
Anatoly Pushkarev
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Pressure ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Lattice Constants ◽  
Scanning Electron

ABSTRACTAlloys of the CuAlS2 – CuFeS2 system were prepared by thermobaric treatment at high pressure of 5.5 GPa and temperatures ranging from 573 to 1573 K and phase formation in the system was investigated using X-ray powder diffraction, optical microscopy and scanning electron microscopy equipped with energy dispersive spectroscopy. The unit-cell parameters (the lattice constants and the unit-cell volume) were computed as a function of the composition. Absence of complete solubility in the (CuAlS2)1-x-(CuFeS2)x system was established. Formation of solid solutions with the tetragonal structure of chalcopyrite was detected for compositions with the molar part of CuFeS2 x not exceeding 0.10.

Phase transitions in ReO3studied by high-pressure X-ray diffraction

2000 ◽  
Vol 33 (2) ◽  
pp. 279-284 ◽  
Author(s):  
J.-E. Jørgensen ◽  
J. Staun Olsen ◽  
L. Gerward
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Powder Diffraction ◽  
Ambient Pressure ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Pressure Phase ◽  
Related Phase

ReO3has been studied at pressures up to 52 GPa by X-ray powder diffraction. The previously observed cubicIm3¯ high-pressure phase was shown to transform to a monoclinic MnF3-related phase at about 3 GPa. All patterns recorded above 12 GPa could be indexed on rhombohedral cells. The compressibility was observed to decrease abruptly at 38 GPa. It is therefore proposed that the oxygen ions are hexagonally close packed above this pressure, giving rise to two rhombohedral phases labelled I and II. The zero-pressure bulk moduliBoof the observed phases were determined and the rhombohedral phase II was found to have an extremely large value of 617 (10) GPa. It was found that ReO3transforms back to thePm3¯mphase found at ambient pressure.

scholarly journals Thermal Analysis, Compressibility, and Decomposition of Synthetic Bastnäsite-(La) to Lanthanum Oxyfluoride

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 212
Author(s):  
Richard L. Rowland ◽  
Barbara Lavina ◽  
Kathleen E. Vander Kaaden ◽  
Lisa R. Danielson ◽  
Pamela C. Burnley
Keyword(s):  
High Temperature ◽  
Equation Of State ◽  
Ambient Temperature ◽  
Evolved Gas Analysis ◽  
Ambient Pressure ◽  
Basic Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Equation ◽  
X Ray

Understanding basic material properties of rare earth element (REE) bearing minerals such as their phase stability and equations of state can assist in understanding how economically viable deposits might form. Bastnäsite is the most commonly mined REE bearing mineral. We synthesized the lanthanum-fluoride end member, bastnäsite-(La) (LaCO3F), and investigated its thermal behavior and decomposition products from 298 K to 1173 K under ambient pressure conditions through thermogravimetric analysis, differential scanning calorimetry, evolved gas analysis, and high temperature powder X-ray diffraction. We also investigated the compressibility of bastnäsite-(La) via single crystal X-ray diffraction in diamond anvil cells at an ambient temperature up to 11.3 GPa and from 4.9 GPa to 7.7 GPa up to 673 K. At ambient pressure, bastnäsite-(La) was stable up to 598 K in air, where it decomposed into CO2 and tetragonal γ-LaOF. Above 948 K, cubic α-LaOF is stable. High temperature X-ray diffraction data were used to fit the Fei thermal equation of state and the thermal expansion coefficient α298 for all three materials. Bastnäsite-(La) was fit from 298 K to 723 K with V0 = 439.82 Å3, α298 = 4.32 × 10−5 K−1, a0 = −1.68 × 10−5 K−1, a1 = 8.34 × 10−8 K−1, and a2 = 3.126 K−1. Tetragonal γ-LaOF was fit from 723 K to 948 K with V0 = 96.51 Å3, α298 = 2.95×10−4 K−1, a0 = −2.41×10−5 K−1, a1 = 2.42×10−7 K−1, and a2 = 41.147 K−1. Cubic α-LaOF was fit from 973 K to 1123 K with V0 = 190.71 Å3, α298 = −1.12×10−5 K−1, a0 = 2.36×10−4 K−1, a1 = −1.73 × 10−7 K−1, and a2 = −17.362 K−1. An ambient temperature third order Birch–Murnaghan equation of state was fit with V0 = 439.82 Å3, K0 = 105 GPa, and K’ = 5.58.

X-ray structural studies of epitaxial yttrium silicide on Si(111)

1994 ◽  
Vol 9 (6) ◽  
pp. 1434-1440 ◽  
Author(s):  
L.J. Martínez-Miranda ◽  
J.J. Santiago-Avilés ◽  
W.R. Graham ◽  
P.A. Heiney ◽  
M.P. Siegal
Keyword(s):  
Unit Cell Volume ◽  
Film Growth ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Correlation Lengths ◽  
X Ray ◽  
Lattice Constants ◽  
Glancing Angle ◽  
Out Of Plane ◽  
The Mean

We performed a series of glancing angle and reflection x-ray diffraction experiments to study both the in-plane and out-of-plane structure of epitaxial YSi2−x films grown on Si(111), with thicknesses ranging from 85 Å to 510 Å. These measurements allowed us to characterize the mean film lattice constants, the position correlation lengths of the film, and the presence and extent of strain as a function of film thickness. We find that the strain along the basal plane increases as a function of increasing thickness to approximately 1% in the 510 Å film; the corresponding out-of-plane strain is such that the film unit cell volume increases as a function of thickness. The corresponding in-plane microscopic strain varies from 0.5% for the 85 Å film to 0.3% for the 510 Å film. We relate our results to the mode of film growth and the presence of pinholes in the films.

Investigation of the crystal structure of a low water content hydrous olivine to 29.9 GPa: A high-pressure single-crystal X-ray diffraction study

2020 ◽  
Vol 105 (12) ◽  
pp. 1857-1865
Author(s):  
Jingui Xu ◽  
Dawei Fan ◽  
Dongzhou Zhang ◽  
Bo Li ◽  
Wenge Zhou ◽  
...  
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Single Crystal ◽  
Water Content ◽  
Structural Changes ◽  
Volume Data ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Water Contents

Abstract Olivine is the most abundant mineral in the Earth's upper mantle and subducting slabs. Studying the structural evolution and equation of state of olivine at high-pressure is of fundamental importance in constraining the composition and structure of these regions. Hydrogen can be incorporated into olivine and significantly influence its physical and chemical properties. Previous infrared and Raman spectroscopic studies indicated that local structural changes occur in Mg-rich hydrous olivine (Fo ≥ 95; 4883–9000 ppmw water) at high-pressure. Since water contents of natural olivine are commonly <1000 ppmw, it is inevitable to investigate the effects of such water contents on the equation of state (EoS) and structure of olivine at high-pressure. Here we synthesized a low water content hydrous olivine (Fo95; 1538 ppmw water) at low SiO2 activity and identified that the incorporated hydrogens are predominantly associated with the Si sites. We performed high-pressure single-crystal X-ray diffraction experiments on this olivine to 29.9 GPa. A third-order Birch-Murnaghan equation of state (BM3 EoS) was fit to the pressure-volume data, yielding the following EoS parameters: VT0 = 290.182(1) Å3, KT0 = 130.8(9) GPa, and K′T0 = 4.16(8). The KT0 is consistent with those of anhydrous Mg-rich olivine, which indicates that such low water content has negligible effects on the bulk modulus of olivine. Furthermore, we carried out the structural refinement of this hydrous olivine as a function of pressure to 29.9 GPa. The results indicate that, similar to the anhydrous olivine, the compression of the M1-O and M2-O bonds are comparable, which are larger than that of the Si-O bonds. The compression of M1-O and M2-O bonds of this hydrous olivine are comparable with those of anhydrous olivine, while the Si-O1 and Si-O2 bonds in the hydrous olivine are more compressible than those in the anhydrous olivine. Therefore, this study suggests that low water content has negligible effects on the EoS of olivine, though the incorporation of water softens the Si-O1 and Si-O2 bond.

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