The determination of the Sb/As content in natural tetrahedrite–tennantite and bournonite–seligmannite solid solution series by Raman spectroscopy

AbstractNatural samples containing tetrahedrite–tennantite, bournonite–seligmannite and geocronite–jordanite from the Coranda-Hondol ore deposit, Romania, were investigated by Raman spectroscopy to determine its capability to provide estimates of solid solutions in three common and widespread sulfosalt mineral series. Raman measurements were performed on extended solid solution series (Td1 to Td97, Bnn25 to Bnn93 and Gcn24 to Gcn67, apfu). The tetrahedrite–tennantite and bournonite–seligmannite solid solution series show strong correlations between spectroscopic parameters ( position, relative intensity and shape of the Raman bands) and the Sb/(Sb+As) content ratio, while Raman spectra of geocronite–jordanite shows no evolution of Raman bands. In order to simplify the method used to estimate the Sb/(Sb+As) content ratio in tetrahedrite–tennantite and bournonite–seligmannite series, several linear equations of the first-order polynomial fit were obtained. The results are in good agreement with electron microprobe data. Moreover, a computer program was developed as an analytical tool for a fast and accurate determination of Sb/(Sb+As) content ratio by at least one spectroscopic parameter. These results indicate that Raman spectroscopy can provide direct information on the composition and structure of the tetrahedrite–tennantite and bournonite– seligmannite series.

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Crystal chemistry, Rietveld refinements and Raman spectroscopy studies of the new solid solution series: Ba3−xSrx(VO4)2 (0≤x≤3)

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2010.03.066 ◽

2010 ◽

Vol 498 (1) ◽

pp. 42-51 ◽

Cited By ~ 14

Author(s):

M. Azdouz ◽

Bouchaib Manoun ◽

R. Essehli ◽

M. Azrour ◽

L. Bih ◽

...

Keyword(s):

Solid Solution ◽

Raman Spectroscopy ◽

Crystal Chemistry ◽

Solid Solution Series ◽

Rietveld Refinements ◽

Solution Series ◽

Spectroscopy Studies

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Structural and Raman spectroscopic characterization of pyroxene-type compounds in the CaCu1−xZnxGe2O6solid-solution series

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s205252061700381x ◽

2017 ◽

Vol 73 (3) ◽

pp. 419-431 ◽

Cited By ~ 1

Author(s):

Günther J. Redhammer ◽

Gerold Tippelt ◽

Andreas Reyer ◽

Reinhard Gratzl ◽

Andreas Hiederer

Keyword(s):

Solid Solution ◽

Raman Spectroscopy ◽

Phase Change ◽

Single Crystal ◽

Spectroscopic Characterization ◽

Phase Changes ◽

Solid Solution Series ◽

Teller Distortion ◽

Cell Parameters ◽

Solution Series

Pyroxene-type germanate compounds with the composition CaCuGe2O6–CaZnGe2O6have been synthesizedviaa solid-state ceramic sintering route. Phase-pure polycrystalline and small single-crystal material was obtained all over the series, representing a complete solid-solution series. Differential thermal analysis, single-crystal X-ray diffraction and Raman spectroscopy were used to characterize phase stability, phase changes and structural alterations induced by the substitution of Cu2+with Zn2+. Whereas pure CaCuGe2O6exhibitsP21/csymmetry with a strong distortion of theM1 octahedra and two different Ge sites, one of them with an unusual fivefold coordination, the replacement of Cu2+by Zn2+induces a chemically driven phase change to theC2/csymmetry. The phase change takes place around Zn2+contents of 0.12 formula units and is associated with large changes in the unit-cell parameters. Here, the increase ofcby as much as 3.2% is remarkable and it is mainly controlled by an expansion of the tetrahedral chains. Further differences between theP21/candC2/cstructures are a more regular chain of edge-sharingM1 octahedra as a consequence of more and more reduced Jahn–Teller distortion and a less kinked, symmetry-equivalent tetrahedral chain. The coordination of the Ca site increases from sevenfold to eightfold with large changes in the Ca—O bond lengths during the phase change. Raman spectroscopy was mainly used to monitor theP21/ctoC2/cphase change as a function of composition, but also as a function of temperature and to follow changes in specific Raman modes throughout the solid-solution series.

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Investigation of the kieserite–szomolnokite solid-solution series, (Mg,Fe)SO4·H2O, with relevance to Mars: Crystal chemistry, FTIR, and Raman spectroscopy under ambient and martian temperature conditions

American Mineralogist ◽

10.2138/am-2019-6983 ◽

2019 ◽

Vol 104 (12) ◽

pp. 1732-1749 ◽

Cited By ~ 6

Author(s):

Dominik Talla ◽

Manfred Wildner

Keyword(s):

Solid Solution ◽

Raman Spectroscopy ◽

Spectral Band ◽

Lattice Parameters ◽

Detailed Knowledge ◽

Solid Solution Series ◽

Solution Series ◽

Near Ir ◽

End Members ◽

First Time

Abstract The investigation of hydrous sulfate deposits and sulfate-cemented soils on the surface of Mars is one of the important topics in the recent scientific endeavor to retrieve detailed knowledge about the planetary water budget and surface weathering processes on our neighbor planet. Orbital visible/near-IR spectra of the surface of Mars indicate kieserite, MgSO4·H2O, as a dominant sulfate species at lower latitudes. However, given the Fe-rich composition of the martian surface, it is very probable that its actual composition lies at an intermediate value along the solid-solution series between the kieserite and szomolnokite (FeSO4·H2O) end-members. Despite the known existence of significant lattice parameter changes and spectral band position shifts between the two pure end-members, no detailed crystal chemical and spectroscopic investigation along the entire kieserite–szomolnokite solid solution range has been done yet. The present work proves for the first time the existence of a continuous kieserite–szomolnokite solid-solution series and provides detailed insight into the changes in lattice parameters, structural details, and positions of prominent bands in FTIR (5200–400 cm–1) and Raman (4000–100 cm–1) spectra in synthetic samples as the Fe/Mg ratio progresses, at both ambient as well as Mars-relevant lower temperatures. Additionally, an UV-Vis-NIR (29 000–3500 cm–1) crystal field spectrum of szomolnokite is presented to elucidate the influence of Fe2+-related bands on the overtone- and combination mode region. The kieserite–szomolnokite solid-solution series established in this work shows Vegard-type behavior, i.e., lattice parameters as well as spectral band positions change along linear trends. The detailed knowledge of these trends enables semi-quantitative estimations of the Fe/Mg ratio that can be applied to interpret martian monohydrated sulfates in data from remote sensing missions on a global scale as well as from in situ rover measurements. Given the knowledge of the surface temperature during spectral measurements, the established temperature behavior allows quantitative conclusions concerning the Fe/Mg ratio. Our understanding of the kieserite–szomolnokite solid-solution series will be well applicable to the Mars 2020 and ExoMars 2020 rover missions that will focus on near IR (0.9 to 3.5 μm) and, for the first time on Mars, Raman spectroscopy.

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