scholarly journals Phase Transition of Silicate Minerals under High Temperature and High Pressure and the Structure of the Earth's Mantle

1965 ◽  
Vol 71 (843) ◽  
pp. 595-605
Author(s):  
Shunichi AKIMOTO
2014 ◽  
Vol 228 ◽  
pp. 56-62 ◽  
Author(s):  
Cuiping Yang ◽  
Toru Inoue ◽  
Akihiro Yamada ◽  
Takumi Kikegawa ◽  
Jun-ichi Ando

2019 ◽  
Vol 40 (4) ◽  
pp. 563-570 ◽  
Author(s):  
Renée M. Ripken ◽  
Stefan Schlautmann ◽  
Remco G.P. Sanders ◽  
Johannes G.E. Gardeniers ◽  
Séverine Le Gac

2018 ◽  
Vol 38 (3) ◽  
pp. 212-223 ◽  
Author(s):  
Chaoshuai Zhao ◽  
Heping Li ◽  
Jianjun Jiang ◽  
Yu He ◽  
Wen Liang

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 75 ◽  
Author(s):  
Linfei Yang ◽  
Lidong Dai ◽  
Heping Li ◽  
Haiying Hu ◽  
Meiling Hong ◽  
...  

The phase stability of epsomite under a high temperature and high pressure were explored through Raman spectroscopy and electrical conductivity measurements in a diamond anvil cell up to ~623 K and ~12.8 GPa. Our results verified that the epsomite underwent a pressure-induced phase transition at ~5.1 GPa and room temperature, which was well characterized by the change in the pressure dependence of Raman vibrational modes and electrical conductivity. The dehydration process of the epsomite under high pressure was monitored by the variation in the sulfate tetrahedra and hydroxyl modes. At a representative pressure point of ~1.3 GPa, it was found the epsomite (MgSO4·7H2O) started to dehydrate at ~343 K, by forming hexahydrite (MgSO4·6H2O), and then further transformed into magnesium sulfate trihydrate (MgSO4·3H2O) and anhydrous magnesium sulfate (MgSO4) at higher temperatures of 373 and 473 K, respectively. Furthermore, the established P-T phase diagram revealed a positive relationship between the dehydration temperature and the pressure for epsomite.


1996 ◽  
Vol 68 (2) ◽  
pp. 182-184 ◽  
Author(s):  
Shigeo Horiuchi ◽  
Lian‐Long He ◽  
Mitsuko Onoda ◽  
Minoru Akaishi

2007 ◽  
Vol 19 (42) ◽  
pp. 425221 ◽  
Author(s):  
Y M Ma ◽  
Q Zhou ◽  
Z He ◽  
F F Li ◽  
K F Yang ◽  
...  

2016 ◽  
Vol 71 (5) ◽  
pp. 439-445 ◽  
Author(s):  
Sebastian J. Metzger ◽  
Florian Ledderboge ◽  
Gunter Heymann ◽  
Hubert Huppertz ◽  
Thomas Schleid

AbstractTransparent single crystals of the scheelite-type Ln[AsO4] phases with Ln = La–Nd are obtained by the pressure-induced monazite-to-scheelite type phase transition in a Walker-type module under high-pressure and high-temperature conditions of 11 GPa at 1100–1300 °C. Coinciding with this transition, there is an increase in density and a reduction in molar volume of about 4.5 % for the scheelite-type phases (tetragonal, I41/a) for La[AsO4] (a = 516.92(4), c = 1186.1(9) pm), Ce[AsO4] (a = 514.60(1), c = 1175.44(2) pm), Pr[AsO4] (a = 512.63(4), c = 1168.25(9) pm), and Nd[AsO4] (a = 510.46(4), c = 1160.32(11) pm) as compared to the well-known monazite-type phases (monoclinic, P21/n). Surprisingly enough, the scheelite-type oxoarsenates(V) exhibit a lower coordination number for the Ln3+ cations (CN = 8 versus CN = 8 + 1), whereas the isolated tetrahedral [AsO4]3– anions (d(As–O) = 168.9–169.3 pm for the scheelites as compared to d(As–O) = 167.1–169.9 pm for the monazites) remain almost unchanged. So the densification must occur because of the loss of two edge-connections of the involved [LnO8+1]15– polyhedra with the [AsO4]3– tetrahedra in the monazite- resulting in exclusively vertex connected [LnO8]13– and [AsO4]3– units in the scheelite-type structure.


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