Rietveld refinement study of pyrite crystals

Paszkowicz, W.; Leiro, J.A.

doi:10.1016/j.jallcom.2005.02.052

Cited by 28 publications

(19 citation statements)

References 53 publications

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“…To confirm the pore existence, we measured the density of the sample. The measured density, 4.813 g/cm 3 , is indeed lower than the theoretical density 5.04 g/cm 3 calculated from the unit-cell dimension (Paszkowicz and Leiro 2005). The porosity calculated from the density data is 5.6% assuming the pores are filled with water.…”

Section: Natural and Synthetic Iron Disulfides (Marcasite And Pyrite)mentioning

confidence: 52%

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Xia

Jing

Etschmann

et al. 2014

American Mineralogist

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25Porosity plays a key role in the formation and alteration of sulfide ore minerals, yet our knowledge 26 of the nature and formation of the residual pores is very limited. Herein, we report the application of 27 ultra small angle neutron scattering and small angle neutron scattering (USANS/SANS) to assess 28 the porosity in five natural sulfide minerals (violarite, marcasite, pyrite, chalcopyrite, and bornite)

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Section: Natural and Synthetic Iron Disulfides (Marcasite And Pyrite)mentioning

confidence: 52%

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Xia

Jing

Etschmann

et al. 2014

American Mineralogist

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“…The measured lattice parameters estimated from HRTEM correspond well to accepted values. 29 Structural and Elemental Characterization. Structural characterization of the resulting pyrite nanocubes is given in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

Iron Pyrite Nanocubes: Size and Shape Considerations for Photovoltaic Application

2012

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Multiple lines of recent research indicate that iron pyrite (FeS(2)) requires a {100}-terminated crystal morphology in order to maintain semiconducting properties. Additionally, the large absorption coefficient of pyrite allows for the near complete absorption of above band gap radiation in <50 nm layers. However, to our knowledge <50 nm pyrite nanocubes have yet to be isolated. Herein, we demonstrate the synthesis of ~37 nm phase pure pyrite nanocubes by manipulating the sulfur chemical potential and ligand environment of the system. Ultraviolet-visible (UV-vis) absorption spectroscopy gives a signal of resonant light scattering indicating strong electronic coupling between nanocubes, which may allow for nanocube films with superior electron mobility. The absorption spectroscopies of cubic and irregular nanocrystals are contrasted and compared with recent theoretical work in order to investigate the effect of shape on electronic properties. Specifically, nanocubes have been found to have absorption characteristics closer to theory as compared to irregular nanocrystals, especially for UV radiation: 250-350 nm. Pyrite nanocubes display an indirect band gap at ~1.1 eV in addition to two direct transitions at ~1.9 and ~3.0 eV, correlating well to theoretical values.

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“…Experimental studies of the lattice parameters of pyrite at different temperatures can be found, however, the majority of temperatures reported are between 294 and 300 K. [42][43][44] If we take these lattice parameters as a function of temperature and extrapolate to zero Kelvin, we can estimate that the lattice parameter of pyrite in the low temperature limit is 5.281 Å. Thermal expansion of lattice parameters would not be completely linear, due to vibrational quantization, and so we can anticipate that the above value is a lower bound to the lattice parameter at absolute zero.…”

Section: A Structure and Phase Stability Of Pyrite And Marcasite Basmentioning

confidence: 99%

Density functional theory study of the relative stability of the iron disulfide polymorphs pyrite and marcasite

et al. 2010

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The performance of density functional theory (DFT) has been widely examined with regard to its ability to predict the properties of minerals, though less attention has been given to the correct determination of the relative stability of structurally similar polymorphs. Here a detailed examination is performed of the numerical and theoretical factors that may influence the structure and relative energetics of two such polymorphs of iron disulfide, namely pyrite and marcasite, within density functional theory. Both the local density approximation and commonly used generalized gradient approximation exchange-correlation functionals, such as PBE, are found to predict that marcasite is more stable than pyrite, at variance with experiment. Allowing for the zero point energy of vibration fails to remedy this discrepancy. While inclusion of a 2 sufficiently large Hubbard U parameter for iron is found to reverse the stability, this comes at the expense of a very poor description of other properties. Examination of three generalized gradient approximations developed specifically for the solid-state, namely AM05, Wu-Cohen and PBEsol, demonstrates that all of these functionals offer a superior description of the structures and relative energies of pyrite and marcasite through correctly predicting that the former is the ground state phase at ambient conditions.

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Rietveld refinement study of pyrite crystals

Cited by 28 publications

References 53 publications

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Iron Pyrite Nanocubes: Size and Shape Considerations for Photovoltaic Application

Density functional theory study of the relative stability of the iron disulfide polymorphs pyrite and marcasite

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