Electrical conductivity measurements of periclase under high pressure and high temperature

2010 ◽  
Vol 405 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Xiaoping Wu ◽  
Baohua Zhang ◽  
Junshan Xu ◽  
Tomoo Katsura ◽  
Shuangmeng Zhai ◽  
...  
2016 ◽  
Vol 174 (3) ◽  
pp. 1033-1041 ◽  
Author(s):  
KeShi Hui ◽  
LiDong Dai ◽  
HePing Li ◽  
HaiYing Hu ◽  
JianJun Jiang ◽  
...  

1997 ◽  
Vol 481 ◽  
Author(s):  
Michael F. Bell ◽  
Georges Dénès ◽  
Zhimeng Zhu

ABSTRACTPrecipitation reactions from aqueous solutions of calcium nitrate and tin(II) fluoride result in the formation of two metastable phases, depending on the reaction conditions. Crystalline CaSn2F6 and the microcrystalline Ca1-xSnxF2 solid solution are obtained, the latter crystallizing in the cubic fluorite (CaF2) type with total Ca/Sn disorder. Both phases are fluoride ion conductors. Electrical conductivity measurements versus temperature and bulk density measurements show that both phases are far from thermodynamic equilibrium at ambient conditions, and thus are metastable. Both decompose to a mixture of SnF2 and CaF2 at high temperature. In addition, CaSn2F6 is chemically unstable in an aqueous medium, in which it looses SnF2 to give the microcrystalline Ca1-xSnxF2 solid solution.


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 54 (23) ◽  
pp. 16654-16658 ◽  
Author(s):  
I. Orgzall ◽  
B. Lorenz ◽  
S. T. Ting ◽  
P.-H Hor ◽  
V. Menon ◽  
...  

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