scholarly journals Determination of the response of pentaerythritol tetranitrate to static high pressure up to 4.2 GPa by neutron diffraction

1997 ◽  
Author(s):  
J.J. Dick ◽  
R.B. von Dreele
Author(s):  
Narangoo Purevjav ◽  
Takuo Okuchi ◽  
Xiaoping Wang ◽  
Christina Hoffmann ◽  
Naotaka Tomioka

Ringwoodite [(Mg,Fe2+)2SiO4 spinel] has been considered as one of the most important host minerals of water in the Earth's deep mantle. Its extensive hydration was observed in high-pressure synthesis experiments and also by its natural occurrence. Water can dissolve into ringwoodite as structurally bound hydrogen cations by substituting other cations, although the hydrogen site and its occupancy remain unclear. In this study, neutron time-of-flight single-crystal Laue diffraction analysis was carried out for synthetic hydrous ringwoodite. Hydrogen cations were found only in the sites in MgO6 octahedra in the ringwoodite structure, which compensated the reduced occupancies of both magnesium and silicon cations. The refined cation occupancies suggest that the most plausible hydration mechanism is that three hydrogen cations simultaneously occupy an MgO6 octahedron, whereas four such hydrogenated octahedra surround a vacant SiO4 tetrahedron.


1979 ◽  
Vol 40 (C5) ◽  
pp. C5-180-C5-182 ◽  
Author(s):  
J. X. Boucherle ◽  
D. Givord ◽  
J. Laforest ◽  
J. Schweizer ◽  
F. Tasset

1985 ◽  
Vol 46 (C8) ◽  
pp. C8-87-C8-92 ◽  
Author(s):  
R. Bellissent ◽  
J. Bigot ◽  
Y. Calvayrac ◽  
S. Lefebvre ◽  
A. Quivy

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.


2020 ◽  
Author(s):  
Satoshi Morooka ◽  
Nobuo Nakada ◽  
Yuhki Tsukada ◽  
Wu Gong ◽  
Takuro Kawasaki ◽  
...  

RSC Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 3577-3581 ◽  
Author(s):  
Nursultan Sagatov ◽  
Pavel N. Gavryushkin ◽  
Talgat M. Inerbaev ◽  
Konstantin D. Litasov

We carried out ab initio calculations on the crystal structure prediction and determination of P–T diagrams within the quasi-harmonic approximation for Fe7N3 and Fe7C3.


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