Characterization of a chalcopyrite from Brazil by Mössbauer spectroscopy and other physicochemical techniques

Mussel, Wagner da Nova; Murad, E.; Fabris, José Domingos; Moreira, W. S.; Barbosa, João Batista Santos; Murta, C. C.; Abrahão, W. P.; Mello, Jaime Wilson Vargas de; Garg, V. K.

doi:10.1007/s00269-007-0156-8

Cited by 10 publications

(5 citation statements)

References 22 publications

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“…No evidence was found from the Rietveld fit to the HRPD and POLARIS data for the coexistence of a tetragonal and cubic chalcopyrite phase that was recently claimed for a specimen from Rio Grande do Sul, Brazil (Mussel et al 2007). Throughout the whole temperature-interval from 4.2 to 300 K, the anion coordinate showed a negligible variation with temperature, with an average value of 0.252(1), this apparently large estimated standard deviation being associated with both the short data-collection times and the small magnitude of the neutron scattering cross-section of sulfur.…”

Section: Temperature Dependence Of the Structural Parametersmentioning

confidence: 81%

THE LOW-TEMPERATURE AND HIGH-PRESSURE THERMOELASTIC AND STRUCTURAL PROPERTIES OF CHALCOPYRITE, CuFeS2

Knight¹,

Marshall²,

Zochowski³

2011

The Canadian Mineralogist

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The thermoelastic properties of a sample of chalcopyrite from the Palabora mine, South Africa, have been investigated in the temperature range 4.2-330 K at ambient pressure, and between 0.22 and 6.81 GPa at ambient temperature. Magnetization measurements indicated a transition to a second antiferromagnetically ordered phase in the region of 53 K; however, all attempts to characterize this magnetic phase by introducing an ordered moment onto the copper site were unsuccessful owing to the small magnitude of the refined magnetic moment. In agreement with other low-temperature crystallographic measurements made on non-antiferromagnetically ordered adamantine-structured semiconducting materials (group IV; I-VII, II-VI, III-V, I-III-VI 2 , II-IV-V 2 compounds), chalcopyrite exhibits negative linear and volumetric thermal expansion over a significant temperature interval. Calculation of the speeds of sound for a number of high-symmetry wave vectors is consistent with Blackman's model for negative thermal expansion. The unit-cell volume and isochoric heat-capacity have been fitted assuming a two-term Debye internal energy function, with consistent values being found for the two characteristic temperatures. The temperature dependence of the thermodynamic Grüneisen parameter shows a deep minimum of ~-3 at T/u 0 ~0.55 (u 0 is the Debye temperature at 0 K) and a high-temperature limit of ~0.7; these results are the first demonstration that a chalcopyrite-structured phase behaves in the characteristic manner of the simpler adamantine-structured semiconducting materials. No systematic variation in either the nuclear nor the magnetic structure was found between 4.2 and 330 K, and the vibrational Debye temperatures derived by fitting the temperature dependence of the isotropic atomic displacement parameters show no relationship to features in the phonon density of states function. The bulk modulus of chalcopyrite is 77(2) GPa, in good agreement with that determined by ab initio calculations and a recent X-ray-diffraction study, and its pressure derivative is 2.0(6). At high pressure, chalcopyrite remains antiferromagnetically ordered until 6.7(2) GPa, at which point a transition to an amorphous phase is observed. Slow decompression of this phase leads to only a limited recovery of the crystalline phase.

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Section: Temperature Dependence Of the Structural Parametersmentioning

confidence: 81%

THE LOW-TEMPERATURE AND HIGH-PRESSURE THERMOELASTIC AND STRUCTURAL PROPERTIES OF CHALCOPYRITE, CuFeS2

Knight¹,

Marshall²,

Zochowski³

2011

The Canadian Mineralogist

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“…The room-temperature spectrum of the second sample (Figure ) is composed of a sextet with an isomeric shift of 0.25 mm/s and hyperfine field of 355 kOe (QS ∼0 mm/s) from Fe 3+ in chalcopyrite, ,,− and the central signal that is notably broader than that of valleriite-1 and is better fitted with four doublets. One of them with IS = 0.22 mm/s appears to belong to Fe 3+ bonded with oxygen in hydroxide layers, and three others with IS ∼0.4 mm/s and QS = 0.49–1.24 mm/s are due to Fe 3+ centers coordinated to 4 S atoms with varying distortion of the local environment (Table S4).…”

Section: Resultsmentioning

confidence: 99%

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

et al. 2021

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Valleriite is of interest as a mineral source of basic and precious metals and as an unusual material composed of two-dimensional (2D) Fe−Cu sulfide and magnesium hydroxide layers, whose characteristics are still very poorly understood. Here, the mineral samples of two types with about 50% of valleriites from Noril'sk ore provenance, Russia, were examined using Cu K-and Fe K-edge X-ray absorption fine structure (XAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), 57 Fe Mossbauer spectroscopy, and magnetic measurements. The Cu K X-ray absorption near-edge structures (XANES) spectra resemble those of chalcopyrite, however, with a higher electron density at Cu + centers and essentially differ from those of bornite Cu 5 FeS 4 ; the Fe K-edge was less informative because of accompanying oxidized Fecontaining phases. The post-edge XANES and extended XAFS (EXAFS) analysis reveal differences in the bond lengths, e.g., additional metal−metal distances in valleriites as compared with chalcopyrite. The XPS spectra confirmed the Cu + and Fe 3+ state in the sulfide sheets and suggest that they are in electron equilibrium with (Mg, Al) hydroxide layers. Mossbauer spectra measured at room temperature comprise central doublets of paramagnetic Fe 3+ , which decreased at 78 K and almost disappeared at 4.2 K, producing a series of hyperfine Zeeman sextets due to internal magnetic fields arising in valleriites. Magnetic measurements do not reveal antiferromagnetic transitions known for bornite. The specific structure and properties of valleriite are discussed in particular as a platform for composites of the 2D transition metal sulfide and hydroxide (mono)layers stacked by the electrical charges, promising for a variety of applications.

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“…1 chalcopyrite were a = 5.27434(9) Å and c = 10.3885(2) Å. These lattice parameters are less than the values reported for stoichiometric chalcopyrite (a = 5.2855 Å and c = 10.4117 Å) [2], and possibly indicative of oxidation of Cu + to Cu 2+ and/or isomorphous substitution of Cu and Fe by other cations with smaller ionic radii. The kaolinite and quartz reflections were excluded from the Rietveld fitting using the exclusion zone.…”

Section: Resultsmentioning

confidence: 52%

“…The occurrence of a single crystalline phase in this chalcopyrite from the Cristalino deposit, Carajás Mineral Province in northern Brazil, presents an interesting differential characteristic compared to the chalcopyrite from the Camaquã copper mine [2]. For the chalcopyrite from Camaquã, the existence of two discrete modifications was attributed to an incomplete conversion of the high-temperature (cubic) variety to the low-temperature (tetragonal) variety, i.e.…”

Section: Discussionmentioning

confidence: 97%

“…A striking feature of the Carajás Mineral Province is Qz the large number of Cu-Au mineralizations that are stratigraphically and tectonically related. Here we describe the properties of a chalcopyrite sample from the Cristalino Cu(Au) deposit, comparing its structural features with previously reported data for a sample from the Camaquã copper mine, a contrasting site in southern Brazil [2].…”

Section: Introductionmentioning

confidence: 98%

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Structural characteristics of chalcopyrite from a Cu(Au) ore deposit in the Carajás Mineral Province, Brazil

et al. 2011

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Characterization of a chalcopyrite from Brazil by Mössbauer spectroscopy and other physicochemical techniques

Cited by 10 publications

References 22 publications

THE LOW-TEMPERATURE AND HIGH-PRESSURE THERMOELASTIC AND STRUCTURAL PROPERTIES OF CHALCOPYRITE, CuFeS2

THE LOW-TEMPERATURE AND HIGH-PRESSURE THERMOELASTIC AND STRUCTURAL PROPERTIES OF CHALCOPYRITE, CuFeS2

Valleriite, a Natural Two-Dimensional Composite: X-ray Absorption, Photoelectron, and Mössbauer Spectroscopy, and Magnetic Characterization

Structural characteristics of chalcopyrite from a Cu(Au) ore deposit in the Carajás Mineral Province, Brazil

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