Soft x-ray emission and Auger electron spectroscopic study of FeS, Fe0.9S, Fe0.875S, and Fe0.5S

Abstract

Soft x-ray emission spectra are obtained of sulfur in FeS, Fe0.9S, Fe0.875S, and Fe0.5S. The structure in the Kβ emission spectra is consistent with recent SCF-Xα calculations for ferrous iron in an octahedral crystal field. Broadening in the Kβ emission spectra with decrease in the Fe-S bond distance is in agreement with the trends predicted by the SCF-Xα calculations. The charge on the sulfur ions is calculated from the shifts of the Kα emission lines. Calculated charges on FeS and Fe0.5S are in good agreement with previous LCAO calculations and photoemission data. Shifts in the Kα line positions for Fe0.9S and Fe0.875S indicate that electroneutrality is satisfied by a reduction in charge on sulfur rather than the coexistence of ferrous and ferric iron. The Auger spectra of sulfur show sharp structure for FeS which gradually disappears as the sulfides become more cation deficient. The Auger data is discussed in terms of changes in the electronic density of states in the valence band as predicted by the SCF-Xα calculations.

Structure of pyrrhotite 5C(Fe9S10)

“…In contrast, 5C also contains some iron atoms with two neighbouring vacancies; however, the four neighbouring planar Fe atoms each contain only one neighbouring vacancy. The presence of increased vacancies surrounding the nearest planar Fe atoms in 4C enhances the contraction in the hyperfine field relative to the 5C case, confirming Kruse's postulation, and indicating increased covalency in the case of 4C relative to 5C, consistent with the measurements of Marusak & Tongson (1979).…”

“…Mö ssbauer studies by Levinson & Treves (1968) and Vaughan & Ridout (1970) found no evidence for the presence of Fe 3+ in pyrrhotite 4C and concluded that the iron sites in pyrrhotite could be sharing the charge, therefore, with a valency of +2.29. Based on a soft X-ray emission and Auger electron spectroscopic study, Marusak & Tongson (1979) found that all iron was present in the +2 state with the sulfide sublattice inhibiting the existence of Fe 3+ through the donation of electrons. Therefore, the oxidation state of all Fe atoms was set to +2 to describe the X-ray scattering.…”

Selective Synthesis of FeS and FeS2 Nanosheet Films on Iron Substrates as Novel Photocathodes for Tandem Dye-Sensitized Solar Cells

“…13,15 Meanwhile, pyrrhotite (FeS) has attracted considerable attention since the 1950s due to its electrical and magnetic properties and phase transitions. [16][17][18][19][20][21] Pyrite thin films were prepared by some techniques, including sulfurization of an electrodeposited or evaporated iron layer, ion beam magnetron sputtering, spray pyrolysis, electrodeposition, MOCVD, and magnetron sputtering. [22][23][24][25][26][27][28][29] In this study, we report that FeS and FeS 2 nanosheet films could be selectively grown on iron substrates through the reaction of iron foil and sulfur powder by a one-step hydrothermal method.…”

“…Therefore, only a thin layer (less than 100 nm thickness) is required in the fabrication of cells based on this material . The photoelectrochemical cell using a pyrite single crystal delivered a solar-to-electrical conversion efficiency of 2.8% with an open circuit voltage ( V oc ) of 187 mV, a short circuit current ( I sc ) of 42 mA/cm 2 , and a fill factor (FF) of 0.5. , Meanwhile, pyrrhotite (FeS) has attracted considerable attention since the 1950s due to its electrical and magnetic properties and phase transitions. – Pyrite thin films were prepared by some techniques, including sulfurization of an electrodeposited or evaporated iron layer, ion beam magnetron sputtering, spray pyrolysis, electrodeposition, MOCVD, and magnetron sputtering. – …”

Chalcopyrite formation through the metathesis of pyrrhotite with aqueous copper

“…The first transition involves the diffusion of copper into the pyrrhotite structure as proposed by Cowper and Rickard (1989). Given that all iron in pyrrhotite is present as iron(II), the iron(III) oxidation state being inhibited by the sulfide sublattice through the donation of electrons (Marusak and Tongson, 1979), copper may be present in pyrrhotite in either the elemental copper (Cu(0) or Cu(I) state. If present as copper(I), then the diffusion of copper through pyrrhotite must coincide with a reverse flow of charge.…”