high pressure pyrite

Electronic Structure Study of the High-Pressure

It is, therefore, important to study the physical and chemical properties of pyrite at high-pressure and high-temperature conditions. Previous studies have shown that, possibly due to the low-spin ...

The pyrite-type high-pressure form of FeOOH | Nature

The pyrite-type high-pressure form of FeOOH. Masayuki Nishi, Yasuhiro Kuwayama, Jun Tsuchiya & Taku Tsuchiya. Nature 547, 205–208 ( 2017) Cite this article. 16k Accesses. 121 Citations....

Electronic structure study of the high-pressure vibrational …

Over the wide pressure range investigated here, all vibrational frequencies depend nonlinearly on pressure; their pressure dependence is quantified by determining the full set of mode Grüneisen parameters and their pressure derivatives. Plane-wave density functional calculations are used to investigate the pressure dependence of the …

High-pressure induced phase transition of FeS 2

Being as the most abundant natural mineral among the iron-based sulphides, iron pyrite (FeS 2) has been extensively investigated.These investigations mainly focused on the known marcasite (Pnnm) and pyrite (P a 3 ¯) phases, due to unknown of high pressure (HP) structural phases of FeS 2.Here, we report a theoretical study up to 300 …

The Pyrite-Type High-Pressure Form of Silica

The Pyrite-Type High-Pressure Form of Silica. Y. Kuwayama, K. Hirose, +1 author. Y. Ohishi. Published in Science 5 August 2005. Materials Science. TLDR. X-ray …

Decomposition and oxidation of pyrite

The pyrite particle was cylindrical and was formed by pressing pyrite powder under high pressure. The pyrite pellet was 6.25 mm in both diameter and length. Based on the observed linear relationship between the unreacted core radius and the reaction time, it was concluded that the decomposition process was controlled by chemical reaction.

The Pyrite-Type High-Pressure Form of Silica | Science

X-ray diffraction measurements showed that a high-pressure form with a pyrite-type structure, denser than other known silica phases, …

Raman Spectroscopic Studies of Pyrite at High Pressure …

3.2. Simultaneous High-Temperature and High-Pressure Study of Pyrite Water reacts with pyrite as a function of temperature, pressure, and time. To avoid the reaction between water and pyrite, methanol–ethanol (4:1) was used as a pressure medium instead of a 20 wt.% NaCl solution [16] to provide hydrostatic pressure.

Sulfur isotope compositions of pyrite from high-pressure metamorphic

Request PDF | Sulfur isotope compositions of pyrite from high-pressure metamorphic rocks and related veins (SW Tianshan, China): Implications for the sulfur cycle in subduction zones | A detailed ...

In Situ Electrochemical Investigation of Acidic Pressure …

pressure oxidation process, gold bearing pyrite is subjected to high-temperature, high-pressure oxidation in autoclaves to destroy pyrite lattice.12,13 This process has been practiced commercially since the early1980s,14 and is widely accepted by the gold mining industry all over the world for its high efficiency and low pollution.

Reaction mechanism of metal and pyrite under high-pressure and high

The changing trends in the lattice energy of the same substance under a high pressure are the same as that of 1/R 0. Under a high pressure, the distance between ions in pyrite decreases due to compression, and the lattice energy increases accordingly. The lattice energy of pyrite shows the most obvious increase between 0–3 GPa (Fig. 3(a ...

In situ high-temperature phase transformation studies on pyrite

In this paper, we report an in situ high-temperature X-ray diffraction study of phase transformations in pyrite under variable environmental conditions (atmospheric pressure (1 atm.), low air pressure (<0.001 atm.), inert and carbon dioxide atmosphere). We observe that while heating of pyrite in air promotes the formation of hematite (α-Fe 2 …

The Pyrite-Type High-Pressure Form of Silica | Science

Abstract. Silica (SiO 2) exhibits extensive polymorphism at elevated pressures. X-ray diffraction measurements showed that a high-pressure form with a pyrite-type structure, denser than other known silica phases, is stable above 268 giga-pascals and 1800 kelvin. The silicon coordination number increases from 6 in the α-PbO …

The pyrite-Type high-pressure form of FeOOH | Request …

At high pressure‐temperature conditions FeOOH decomposes forming oxygen‐rich fluid and different mixed valence iron oxides (previously known phases of Fe 2 O 3, Fe 3 O 4, Fe 5 O 7, and ...

The pyrite-type high-pressure form of silica

X-ray diffraction measurements showed that a high-pressure form with a pyrite-type structure, denser than other known silica phases, is stable above 268 giga-pascals and 1800 kelvin. The silicon coordination number increases from 6 in the alpha-PbO2-type phase to 6+2 in the pyrite-type phase, leading to a large increase in density …

High-Pressure Synthesis of High-Entropy Metal Disulfides with Pyrite

To test the stability of high-pressure phases, we annealed the samples at ambient pressure with flowing nitrogen gas. A pyrite single phase of (Fe, Co, Ni, Cu)S 2 decomposed into pyrite-type phases and the NiAs-type phase after annealing at 400 °C. The phase of the sample prepared at high pressure was not stable at ambient pressure …

The pyrite-type high-pressure form of FeOOH

the high-pressure behaviour of hydroxides in the deep Earth. FeOOH, AlOOH and SiO 2 have the same CaCl 2 -type crystal struc - ture at high pressure, and SiO 2 and δ-AlOOH transform into pyrite-

Transition metal pyrite dichalcogenides. High-pressure …

DOI: 10.1021/IC50069A008 Corpus ID: 95559793; Transition metal pyrite dichalcogenides. High-pressure synthesis and correlation of properties @article{Bither1968TransitionMP, title={Transition metal pyrite dichalcogenides.

Raman Spectroscopic Studies of Pyrite at High …

Variations in the Raman spectra of pyrite were studied from 113 to 853 K at room pressure with a Linkam heating and freezing stage, and for 297–513 K and pressures up to 1.9 GPa with a hydrothermal …

The pyrite-type high-pressure form of FeOOH

The pyrite-type high-pressure form of FeOOH. Water transported into Earth's interior by subduction strongly influences dynamics such as volcanism and plate tectonics. Several recent studies have reported hydrous minerals to be stable at pressure and temperature conditions representative of Earth's deep interior, implying that surface water ...

High-Pressure Evolution of Crystal Bonding Structures and …

Recent conflicting reports on the high-pressure structural evolution of iron oxide-hydroxide (FeOOH) offer starkly contrasting scenarios for the hydrogen and oxygen cycles in Earth's interior. ... Magnetism-Vanishing Stabilizes the Pyrite-Type 3d Transition Metal Peroxides at High Pressures. The Journal of Physical Chemistry C 2020, 124 (18 ...

The band gap and electrical resistivity of FeS2-pyrite at high

The band gap of FeS2 is indirect throughout this pressure range and decreases linearly with pressure at a rate of −1.13 (9)×10−2 eV/GPa. If this linear trend continues, FeS2 is expected to ...

High-pressure Raman spectroscopic studies of FeS2 pyrite

Abstract We report micro-Raman spectroscopic studies of FeS2 pyrite in the diamond-anvil cell under hydrostatic and non-hydrostatic conditions to 55 GPa at room temperature. Four out of five Raman-active modes are resolved with helium as a pressure-transmitting medium to highest pressures. The fifth mode, Tg(2) [377 cm-1], is weak and …

FeO2 and FeOOH under deep lower-mantle conditions and Earth

Using a Nd-doped Y 3 Al 5 O 12 laser system 7 to heat the sample to 1,800 K in situ at high pressure, the sample became semi-transparent, suggesting that a chemical reaction had occurred.

High-pressure form of pyrite-type germanium dioxide

Analogous pyrite-type structures have been experimentally found at high pressure in SnO 2, RuO 2, PbO 2 [56] and GeO 2 [57]. Relative enthalpies of different phases are shown inFig. ...

Altered chemistry of oxygen and iron under deep Earth …

The conventional wisdom, however, is facing a change in light of the recent discovery of the high-pressure pyrite-structured iron superoxide FeO 2 which has O/Fe ratio even higher than Fe 2 O 3 ...

(PDF) High-pressure Raman spectroscopic studies of FeS 2 pyrite

, pyrite, Raman spectroscopy, high pressure, diamond-anvil cell. In t ro du c tio n. T. HE transition metal dichalcogenide FeS. 2, pyrite, is the most abundant of the sulphide minerals and. common ...

Pyrite form of group-14 element pernitrides synthesized at high

The chemical reaction of group-14 elements with molecular nitrogen at pressures above 60 GPa successfully leads to the formation of pyrite-type pernitrides. These new crystalline group-14 elemental pernitrides were found to show a bulk modulus higher than the other known group-14 elemental nitrides. Our resu

The Pyrite-Type High-Pressure Form of Silica | Semantic …

X-ray diffraction measurements showed that a high-pressure form with a pyrite-type structure, denser than other known silica phases, is stable above 268 giga-pascals and 1800 kelvin. The silicon coordination number increases from 6 in the α-PbO2-type phase to 6+2 in the pyrite-type phase, leading to a large increase in density by …

Pyrite form of group-14 element pernitrides synthesized at high …

The chemical reaction of group-14 elements with molecular nitrogen at pressures above 60 GPa successfully leads to the formation of pyrite-type pernitrides, which offer significant new progress in the solid-state chemistry of nitrides. The chemical reaction of group-14 elements with molecular nitrogen at pressures above 60 GPa …