XAFS study on the location of Cu and Mn in a greenish blue elbaite from Alto dos Quntos mine, Brazil

Sugiyama, Kazumasa; Arima, Hiroshi; Konno, Hajime; Mikouchi, T.

doi:10.2465/jmps.161011

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…These authors described a Mn K-edge XANES spectrum of that Cu-and Mn-bearing tourmaline together with spectra of MnO and Mn 2 O 3 . As the edge position for that tourmaline was lying between those of the standard oxides, [42] suggested a mixed valence state of Mn. They obtained a population of Mn 2+ /(Mn 2+ + Mn 3+ ) = 0.6 by its edge energy relative to those of the standard oxides.…”

Section: Theory and Correlationsmentioning

confidence: 94%

“…We also plotted tourmaline samples from the Alto dos Quintos mine, which is also in the Rio Grande do Norte State, Brazil [22,27,41,42] (for all samples the light elements B, Li, H were calculated as described above). These samples contain up 0.49 wt % Bi 2 O 3 , but almost no Pb (≤0.02 wt % PbO) [27].…”

Section: Theory and Correlationsmentioning

confidence: 99%

“…This time the correlation is even getting better (R 2 = 0.94; Figure 6). Correlation between the average X-site charge (only Na 1+ , Ca 2+ , K 1+ ) in Cu-bearing tourmalines from the Alto dos Quintos mine, Rio Grande do Norte State, Brazil (samples from [22,27,41,42]). Figure 6.…”

Section: Theory and Correlationsmentioning

confidence: 99%

“…It should be mentioned that a recent X-ray absorption fine structure (XAFS) study on the location of Cu and Mn in fluor-elbaite with CuO = 1.08 wt % and MnO total = 1.58 wt % from the Alto dos Quintos mine was published by [42]. These authors described a Mn K-edge XANES spectrum of that Cu-and Mn-bearing tourmaline together with spectra of MnO and Mn 2 O 3 .…”

Section: Theory and Correlationsmentioning

confidence: 99%

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Considerations About Bi and Pb in the Crystal Structure of Cu-Bearing Tourmaline

Ertl

Bačík

2020

Minerals

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Copper- and Mn-bearing elbaitic tourmaline (“Paraíba tourmaline”) sometimes contains significant amounts of Pb and Bi. Their position in the tourmaline crystal structure was studied with correlation analysis and bond valence calculations. Correlations between the F content and the X-site charge allow predicting the X-site occupancy. Three sets of tourmaline analyses were studied: (1) Pb-rich tourmalines from the Minh Tien pegmatite, Vietnam; (2) Cu-, Pb- and Bi-bearing tourmalines from the Mulungu mine, Brazil; (3) Cu- and Bi-bearing tourmalines from the Alto dos Quintos mine, Brazil. Two correlations were plotted: (1) the charge by considering only Na1+, Ca2+ and K1+; (2) the charge by adding Pb2+ and Bi3+ to the X-site charge. When plotting correlations for the Minh Tien tourmalines, the correlation significantly improves by adding Pb2+ to the X site. For the Alto dos Quintos tourmalines, only a slight increase of the correlation coefficient is observed, while such a correlation for tourmalines from Mulungu interestingly shows a slight decrease of the correlation coefficient. Bond valence calculations revealed that Bi3+ and Pb2+ can indeed occupy the X site via BiLi(NaAl)−1, PbLi(NaCu)−1 and possibly PbCu(NaAl)−1 substitutions as seen in the investigated tourmaline samples. At the Y site, Pb4+ can be substituted via PbLi(AlCu)−1, and PbVO(AlVOH)−1, while Bi5+ does not have any stable arrangement in Cu-bearing fluor-elbaite. The occurrence of Pb4+ at the Y site could be one explanation for the results of the correlations of the Mulungu tourmalines. Another explanation could be that during the tourmaline crystallization some additional Bi and Pb came into the pegmatitic system and hence disturbed the correlation between the average X-site charge and the F content. Further plots of such correlations in “Paraíba tourmaline” samples might also help to distinguish between the worldwide localities of these rare and sought-after tourmalines.

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Section: Theory and Correlationsmentioning

confidence: 94%

Section: Theory and Correlationsmentioning

confidence: 99%

Section: Theory and Correlationsmentioning

confidence: 99%

Section: Theory and Correlationsmentioning

confidence: 99%

See 2 more Smart Citations

Considerations About Bi and Pb in the Crystal Structure of Cu-Bearing Tourmaline

Ertl

Bačík

2020

Minerals

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“…XANES data are quite sensitive to the electronic states of the X-ray absorbing atoms. Therefore, they are useful to characterize the valence states of minor elements in minerals (Sugiyama et al, 2016;Sugiyama et al, 2017). As shown in Figure 3, the edge position of the XANES of the Mn-bearing andalusite sample is identical to that of Mn 2 O 3 , suggesting that the Mn atoms are in the +3 oxidation state.…”

Section: Locations Of Mn and Fementioning

confidence: 96%

Determination of the locations of Mn and Fe in Mn–bearing andalusite by anomalous X–ray scattering and X–ray absorption fine structure analyses

Arima

Tani

Sugiyama

et al. 2018

Journal of Mineralogical and Petrological Sciences

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Local structural features around Mn and Fe in Mn-bearing andalusite from Västanåberget, Sweden were investigated by anomalous X-ray scattering (AXS) and X-ray absorption fine structure (XAFS). The X-ray absorption near edge structure (XANES) spectra indicate that all of the Mn and Fe atoms are in +3 oxidation state. Both the electron density map of Mn obtained by AXS and simulated multiple-scattering extended X-ray absorption fine structure (EXAFS) spectra indicate that the Mn atoms exclusively occupy Al1 sites. Further, the EXAFS analysis indicates that the first neighbor coordinated to Mn at the Al1 site shows a complete structural relaxation and Jahn-Teller distortion owing to Mn 3+. In addition, the EXAFS analyses reveal that Fe occupies both Al1 and Al2 sites. The Fe site occupancy ratio (Fe at Al2 to total Fe) in the Mn-bearing andalusite sample is 40-50%. Employing the local structural information around Mn and Fe, a conventional single-crystal structural refinement converged at R = 2.34% with a structural formula of (Al 0.82 Mn 0.16 Fe 0.02) [6] (Al 0.99 Fe 0.01) [5] SiO 5 (space group Pnnm with a = 7.8538(9), b = 7.9463(9), c = 5.5867(6) Å).

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Direct detection of the crystal form of an active pharmaceutical ingredient in tablets by X-ray absorption fine structure spectroscopy

Huang

Suzuki²,

Ito³

et al. 2022

International Journal of Pharmaceutics

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XAFS study on the location of Cu and Mn in a greenish blue elbaite from Alto dos Quntos mine, Brazil

Abstract: The local structure of Cu and Mn in a greenish-blue elbaite from Alto dos Quintos, Brazil, was studied by using X-ray absorption fine structure (XAFS) spectroscopy. The observed local structural features suggest the distribution of Cu 2+ , Mn 2+ , and Mn 3+ at the distorted Y-site.

Cited by 7 publications

References 16 publications

Considerations About Bi and Pb in the Crystal Structure of Cu-Bearing Tourmaline

Considerations About Bi and Pb in the Crystal Structure of Cu-Bearing Tourmaline

Determination of the locations of Mn and Fe in Mn–bearing andalusite by anomalous X–ray scattering and X–ray absorption fine structure analyses

Direct detection of the crystal form of an active pharmaceutical ingredient in tablets by X-ray absorption fine structure spectroscopy

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