Pyrite Structure And Structure
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- Pyrite Structure And Structure
We consider general anisotropic nearest-neighbor magnetic exchange in the pyrite structure where the magnetic ions occupy the fcc sites. We show how the Dzyaloshinsky-Moriya interaction can stabilize the anticollinear spin configuration observed in ${mat{MnTe}}_{2}$ when T is slightly below ${mathit{T}}_{mathit{N}}$. As an alternative explanation, we also …
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Unfortunately, little is known Complete first-order Raman spectra of the pyrite structure compounds FeS:,, MnS; and SiP:, 871 about the band structure of the materials under study, especially about above-gap resonances [12, 18]. Therefore we cannot a priori exclude resonance con- ditions leading to d =(= e.
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The pyrite structure, which is favoured by metals with six or more non-bonding d electrons, and which includes pyrite, cattierite, vaesite, cobaltite and gersdorffite, is ... greater than that in pyrite (Table 3). In the structures of marcasite, arsenopyrite and killingite, the octahedra share edges lying in the 001 plane ; as a consequence of ...
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From these, untwinned and non-intergrown crystals, as checked by preces- sion photographs, were selected for data collection. The structure factors of the pyrite structure fall into the following classes according to the parities of the indices hkl: for h, k, l all even or all odd, all atoms contribute; for h, k, l with mixed parities, only
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marcasite on pyrite, and the electronic structures of the bulk phases and the pyrite-marcasite interface, will be analyzed to investigate the marcasite hypothesis (ii). II. BACKGROUND A. Pyrite crystal structure The formula unit of pyrite is FeS 2, where the oxidation statesofFeandSare+IIand−I,respectively.16 Thestructure belongs to the space ...
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The sample in [34] has a pyrite-like structure with the P a 3 space group. The conventional unit cell contains four formula units of Fe S 2. The Fe S 2 pyrite structure is described by two interpenetrating fcc sublattices. Fe atoms are situated at the face-centered site of one sublattice and S 2 molecules are situated on the other, giving a ...
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Figure 2 (a) Selected Raman spectra of collected at a pressure increase run. Numbers denote pressure values in GPa. Mode assignment for the -type structure is presented at the ambient pressure spectrum, and for the pyrite-type structure, at 20.2 GPa.(b) and (c) Pressure dependence of the frequencies of the librational mode (double degenerated mode in the pyrite …
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In this study, ed ceramics with hierarchical closed-cell pore structures (HPS-FC) were successfully prepared using pyrite-rich cyanide tailing (CT) and fly ash. The formation mechanism of the hie...
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Arsenian pyrite containing large amounts of minor and trace elements is widespread in low- and high-temperature hydrothermal systems and sedimentary environments (e.g., Cline, 2001, Fleet and Mumin, 1997, Hofstra and Cline, 2000, Kolker et al., 2003, Large et al., 2009, Reich et al., 2005).Indications of the potential importance of NPs as hosts for trace …
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electronic structures of the bulk phases and the pyrite-marcasiteinterface will be analyzed, to investigate the marcasite hypothesis (ii). II. BACKGROUND A. Pyrite crystal structure The formula unit of pyrite is FeS2, where the oxidation states of Fe and S are +II and −I, respectively.16 The structure belongs to the space group Pa¯3.
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A comparison of the refined structure with other pyrite structures suggests that copper in CuS 2 has a formal valence of 2+ and three antibonding electrons. Also, the CuS 6 octahedron is …
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Pyrite is a polymorph of marcasite, which means that it has the same chemistry, FeS2, as marcasite; but a different structure and therefore different symmetry and crystal shapes. Pyrite is difficult to distinguish from marcasite when a lack of clear indicators exists. Pyrite's structure is analogous to galena's structure with a formula of PbS.
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In the present work, several pyrite/arsenopyrite interfaces are investigated aiming to provide a better understanding of the structure, stability, electronic, and mechanical properties of the interface as an initial step to understand the oxidation mechanism of pyrite associated …
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Sedimentary, magmatic, metamorphic, and hydrothermal deposits. Common world wide. Link to MinDat Location Data. From the Greek, pyrites lithos, "stone which strikes fire," in allusion …
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ChemSpider record containing structure, synonyms, properties, vendors and database links for Pyrite,, Dithioxoiron
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Reflement of the structure in space group Pa3 using 209 intensity data gives a weighted re-sidual of 0.014 and x(S) : 0.39878(5). A comparison of the refined structure with other pyrite …
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The least-squares structure refinements were undertaken using a full-profile Rietveld-type program DBWS-9006PC. As an example of one refinement detailed Rietveld refinement parameters are presented for the main phase pyrite FeS 2 prepared at 200°C for 24 h. The quantities used to estimate the agreement between the observations and the model …
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However, limited information about the structure sensitivity of pyrite is known. Flotation is an interface reaction involving gas, liquid, and solid. In coal flotation, oily reagents are generally used as collectors, air bubbles as carriers. Different crystal facets of pyrite have different affinity with air/water/oil, which has great influence ...
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Arsenic in pyrite is reduced, found in the pyrite structure and in the marcasite-like lamellae (Dódony et al. 1996). The only report of oxidized arsenic (as As 3+ ) in the pyrite structure was ...
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A few studies (Guevremont et al., 1998a, Elsetinow et al., 2000) have focused on the structure sensitivity of pyrite oxidation.These studies compared the nature of oxidation products and rate between the {1 0 0} and {1 1 1} crystal faces. It was revealed that oxidation of the outermost surface of the {1 1 1} crystallographic face proceeds to a greater extent than …
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The Fe neighbor at 2.35 Å as well as the following Fe and S shells indicates a substitution of S by Se in selenide-doted pyrite, yielding in a FeS x Se y compound which may be described best by a slightly distorted pyrite structure (Fig. 8 d). The differences in crystal structure can be compared with natural pyrite structure (Fig. 8 c). As ...
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In this paper, we investigate these claims, via density-functional theory (DFT), by examining the electronic structure, bulk, surface, and interfacial energies of pyrite and …
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The XRD results exhibit a cubic pyrite structure of cobalt-doped FeS 2 films. The average crystal size increases with the increase of cobalt concentration. The temperature dependence of thin film resistance has been investigated, and the results fit well with the Arrhenius equation. The doping effect can interpret as the variation of the ...
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Group of isostructural sulphide species sharing the Pa-3 space group, with a diploidal structure in which the "A" atoms occupy a face-centred cubic lattice position and the "X" atoms are in dumbbell-like pairs parallel to the four cube diagonals of the lattice, with each "A" atom surrounded by six "X" atoms in octahedral coordination - each pair of "X" atoms coordinated to …
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The Structure of Marcasite.---An arrangement of atoms and valence electrons, which is consistent with all known experimental facts, is proposed for marcasite (Fe${mat{S}}_{2}$). The arrangement around each atom is very similar to that in pyrite. The sulfur atoms are in pairs. Each sulfur is bonded, by pairs of electrons, to one sulfur and four iron atoms, and each iron atom to …
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Structures of the pyrite (001)–marcasite (101) interface for and (a), (b) (rendered by VESTA). Black (white) spheres are Fe (S) atoms. ... PBE band structure of (a) pyrite and (b) marcasite. Both of them are indirect-gap materials. High symmetry points correspond to those in Ref. 28. The LDA and AM05 band structures look very similar and are ...
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In some cases, pyrite contains small quantities of what is known as 'invisible gold' – gold that is incorporated within the pyrite structure itself, adding a layer of mischief to an already ...
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The stability of hauerite (MnS 2 ) as compared to that of pyrite (FeS 2 ) can be explained by the long Mn–S distance and departure from the typical pyrite-type structures. The structural differences of MnX 2 compounds (X=S, Se, and Te) are the result of spin configurations that are different than those of other MX 2 compounds; however, the arrangement of d -electrons and …
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The pyrite-type structures of transition-metal dichalcogenides MX2 have undergone intensive investigations in recent years. While qualitative energy level schemes have ... The simple-cubic pyrite structure. This may be formed from a face-centred rocksalt array by replacing the anions by S2 pairs with their diatomic axes oriented equally along ...
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They are formed in a tetragonal structure. In bulk pyrite, each Fe atom is coordinated with six S atoms, forming an octahedral structure, and the S atoms form a tetragonal structure with three Fe atoms and one S atom. In addition, the S 2 2-anion (S–S bond), with a dumbbell structure, exists in pyrite. This is different from that in ...
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Clean pyrite {100} surfaces, generated by cleaving in UHV, were investigated using scanning tunneling microscopy and spectroscopy for the purpose of understanding the electronic …
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Changes in the crystal structure properties before and after Co doping of pyrite were analyzed based on band structure, density of states (DOS), electron density difference, and Mulliken population. Differences in hydrophobicity and collector adsorption between pyrite and Co-doped pyrite were investigated at the molecular and atomic levels.
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For example, FeS 2 has the pyrite structure, which is related to the NaCl structure. The reason is that FeS 2 is not Fe 4+ (S 2-) 2, but is actually Fe 2+ (S 22-), where S 22- is the disulfide anion …
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Stability, Structure, and Electronic Properties of the Pyrite/Arsenopyrite Solid–Solid Interface–A DFT Study
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top 50 structures with relatively low-energy in the CA-LYPSO structure searches are reoptimized by spin po-larized DFT+U calculations to identify the true ground state structures of FeO2 under different pressures. The underlying first-principles structural relaxations and electronic property calculations are carried out using
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Surface thermodynamics. We first evaluate the relative energies of the various crystallographic facets in pyrite and marcasite and their tendency to adsorb OH − and H 3 O + ions, as given in ...
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