A new high pressure phase of sodium formate dihydrate; an experimental and computational study

2007 ◽  
pp. 2014 ◽  
Author(s):  
Martin Walker ◽  
Carole A. Morrison ◽  
David R. Allan ◽  
Colin R. Pulham ◽  
William G. Marshall
Keyword(s):  
High Pressure ◽  
Computational Study ◽  
Sodium Formate ◽  
High Pressure Phase ◽  
Pressure Phase

scholarly journals Compressibility and Phase Stability of Iron-Rich Ankerite

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 607
Author(s):  
Raquel Chuliá-Jordán ◽  
David Santamaria-Perez ◽  
Javier Ruiz-Fuertes ◽  
Alberto Otero-de-la-Roza ◽  
Catalin Popescu
Keyword(s):  
High Pressure ◽  
Density Functional ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
High Pressure Phase ◽  
Stable Phase ◽  
Pressure Derivative ◽  
Reversible Phase Transition ◽  
Murnaghan Equation ◽  
Pressure Phase

The structure of the naturally occurring, iron-rich mineral Ca1.08(6)Mg0.24(2)Fe0.64(4)Mn0.04(1)(CO3)2 ankerite was studied in a joint experimental and computational study. Synchrotron X-ray powder diffraction measurements up to 20 GPa were complemented by density functional theory calculations. The rhombohedral ankerite structure is stable under compression up to 12 GPa. A third-order Birch–Murnaghan equation of state yields V0 = 328.2(3) Å3, bulk modulus B0 = 89(4) GPa, and its first-pressure derivative B’0 = 5.3(8)—values which are in good agreement with those obtained in our calculations for an ideal CaFe(CO3)2 ankerite composition. At 12 GPa, the iron-rich ankerite structure undergoes a reversible phase transition that could be a consequence of increasingly non-hydrostatic conditions above 10 GPa. The high-pressure phase could not be characterized. DFT calculations were used to explore the relative stability of several potential high-pressure phases (dolomite-II-, dolomite-III- and dolomite-V-type structures), and suggest that the dolomite-V phase is the thermodynamically stable phase above 5 GPa. A novel high-pressure polymorph more stable than the dolomite-III-type phase for ideal CaFe(CO3)2 ankerite was also proposed. This high-pressure phase consists of Fe and Ca atoms in sevenfold and ninefold coordination, respectively, while carbonate groups remain in a trigonal planar configuration. This phase could be a candidate structure for dense carbonates in other compositional systems.

scholarly journals A Short Review of Current Computational Concepts for High-Pressure Phase Transition Studies in Molecular Crystals

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 81 ◽  
Author(s):  
Denis A. Rychkov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Organic Compounds ◽  
Computational Study ◽  
Molecular Crystals ◽  
High Pressure Phase ◽  
Advantages And Disadvantages ◽  
High Pressure Phase Transition ◽  
Pressure Phase ◽  
Transition Studies

High-pressure chemistry of organic compounds is a hot topic of modern chemistry. In this work, basic computational concepts for high-pressure phase transition studies in molecular crystals are described, showing their advantages and disadvantages. The interconnection of experimental and computational methods is highlighted, showing the importance of energy calculations in this field. Based on our deep understanding of methods’ limitations, we suggested the most convenient scheme for the computational study of high-pressure crystal structure changes. Finally, challenges and possible ways for progress in high-pressure phase transitions research of organic compounds are briefly discussed.

ChemInform Abstract: The High-Pressure Phase of MgB2C2.

ChemInform ◽  
2011 ◽  
Vol 42 (8) ◽  
pp. no-no
Author(s):  
Michael Woerle ◽  
Urs Fischbach ◽  
Daniel Widmer ◽  
Frank Krumeich ◽  
Reinhard Nesper ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Phase ◽  
Pressure Phase

High-pressure phase transitions in AlSb

2001 ◽  
Vol 62 (5) ◽  
pp. 941-949 ◽  
Author(s):  
H. Hirano ◽  
S. Uehara ◽  
A. Mori ◽  
A. Onodera ◽  
K. Takemura ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Pressure Phase ◽  
Pressure Phase

scholarly journals Magnetic Properties and Single Crystal Growth of a Spin Gapped Compound, High Pressure Phase of (VO)2P2O7.

1999 ◽  
Vol 46 (9) ◽  
pp. 1014-1019
Author(s):  
Takashi Saito ◽  
Masaki Azuma ◽  
Mikio Takano ◽  
Zenji Hiroi ◽  
Yasuo Narumi ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
High Pressure Phase ◽  
Pressure Phase
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