Non-stoichiometry and local order in minerals with the rockbridgeite structure

Ian Edward Grey, Tim Williams, Anthony R. Kampf, John D. Cashion, Yesim Gozukara, Colin M. Macrae, Erich Keck

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

A non-stoichiometric frondelite from the Hagendorf Süd pegmatite, Bavaria, has been studied using chemical and thermal analyses, electron diffraction (ED), Mössbauer spectroscopy and synchrotron single-crystal structure analysis. The structural formula, with occupancies of the M1, M2 and M3 sites given in sequence, is (Fe3 +)(Mn2 + 0.67Zn0.20Fe2 + 0.08Fe3 + 0.70)S 1.65(Fe3 + 2.30) (PO4)3(OH)4.9(H2O)0.1. The non-stoichiometric frondelite contains an excess of 0.3 atoms in the M3 site and a deficiency of 0.35 atoms in the M2 site. The ED patterns show rows of reflections that violate the reflection extinctions for Bbmm, and which are due to a local ordering of Fe3 þ and vacancies in the M3 sites. Based on the ED results, a model was developed in space group Pnma, in which planes containing corner-shared octahedral dimers of M3 atoms are ordered on a scale of ∼6 nm. The Pnma model was refined successfully against the synchrotron single-crystal data. Non-stoichiometry can be explained within the Pnma local-order model by distortions at the M3 sites in non-stoichiometric regions, where local, barbosalite-like, trimeric chains of face-sharing octahedra are formed.

Original languageEnglish
Pages (from-to)773-783
Number of pages11
JournalEuropean Journal of Mineralogy
Volume30
Issue number4
DOIs
Publication statusPublished - 2018

Keywords

  • Crystal structure
  • Electron diffraction
  • Frondelite
  • Local order
  • Mössbauer spectra
  • Non-stoichiometry
  • Thermal analyses

Cite this

Grey, I. E., Williams, T., Kampf, A. R., Cashion, J. D., Gozukara, Y., Macrae, C. M., & Keck, E. (2018). Non-stoichiometry and local order in minerals with the rockbridgeite structure. European Journal of Mineralogy, 30(4), 773-783. https://doi.org/10.1127/ejm/2018/0030-2734
Grey, Ian Edward ; Williams, Tim ; Kampf, Anthony R. ; Cashion, John D. ; Gozukara, Yesim ; Macrae, Colin M. ; Keck, Erich. / Non-stoichiometry and local order in minerals with the rockbridgeite structure. In: European Journal of Mineralogy. 2018 ; Vol. 30, No. 4. pp. 773-783.
@article{04a8bb4ba65a47bebe27a5342fcdbf2b,
title = "Non-stoichiometry and local order in minerals with the rockbridgeite structure",
abstract = "A non-stoichiometric frondelite from the Hagendorf S{\"u}d pegmatite, Bavaria, has been studied using chemical and thermal analyses, electron diffraction (ED), M{\"o}ssbauer spectroscopy and synchrotron single-crystal structure analysis. The structural formula, with occupancies of the M1, M2 and M3 sites given in sequence, is (Fe3 +)(Mn2 + 0.67Zn0.20Fe2 + 0.08Fe3 + 0.70)S 1.65(Fe3 + 2.30) (PO4)3(OH)4.9(H2O)0.1. The non-stoichiometric frondelite contains an excess of 0.3 atoms in the M3 site and a deficiency of 0.35 atoms in the M2 site. The ED patterns show rows of reflections that violate the reflection extinctions for Bbmm, and which are due to a local ordering of Fe3 {\th} and vacancies in the M3 sites. Based on the ED results, a model was developed in space group Pnma, in which planes containing corner-shared octahedral dimers of M3 atoms are ordered on a scale of ∼6 nm. The Pnma model was refined successfully against the synchrotron single-crystal data. Non-stoichiometry can be explained within the Pnma local-order model by distortions at the M3 sites in non-stoichiometric regions, where local, barbosalite-like, trimeric chains of face-sharing octahedra are formed.",
keywords = "Crystal structure, Electron diffraction, Frondelite, Local order, M{\"o}ssbauer spectra, Non-stoichiometry, Thermal analyses",
author = "Grey, {Ian Edward} and Tim Williams and Kampf, {Anthony R.} and Cashion, {John D.} and Yesim Gozukara and Macrae, {Colin M.} and Erich Keck",
year = "2018",
doi = "10.1127/ejm/2018/0030-2734",
language = "English",
volume = "30",
pages = "773--783",
journal = "European Journal of Mineralogy",
issn = "0935-1221",
publisher = "E Schweizerbart Science Publishers",
number = "4",

}

Grey, IE, Williams, T, Kampf, AR, Cashion, JD, Gozukara, Y, Macrae, CM & Keck, E 2018, 'Non-stoichiometry and local order in minerals with the rockbridgeite structure', European Journal of Mineralogy, vol. 30, no. 4, pp. 773-783. https://doi.org/10.1127/ejm/2018/0030-2734

Non-stoichiometry and local order in minerals with the rockbridgeite structure. / Grey, Ian Edward; Williams, Tim; Kampf, Anthony R.; Cashion, John D.; Gozukara, Yesim; Macrae, Colin M.; Keck, Erich.

In: European Journal of Mineralogy, Vol. 30, No. 4, 2018, p. 773-783.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Non-stoichiometry and local order in minerals with the rockbridgeite structure

AU - Grey, Ian Edward

AU - Williams, Tim

AU - Kampf, Anthony R.

AU - Cashion, John D.

AU - Gozukara, Yesim

AU - Macrae, Colin M.

AU - Keck, Erich

PY - 2018

Y1 - 2018

N2 - A non-stoichiometric frondelite from the Hagendorf Süd pegmatite, Bavaria, has been studied using chemical and thermal analyses, electron diffraction (ED), Mössbauer spectroscopy and synchrotron single-crystal structure analysis. The structural formula, with occupancies of the M1, M2 and M3 sites given in sequence, is (Fe3 +)(Mn2 + 0.67Zn0.20Fe2 + 0.08Fe3 + 0.70)S 1.65(Fe3 + 2.30) (PO4)3(OH)4.9(H2O)0.1. The non-stoichiometric frondelite contains an excess of 0.3 atoms in the M3 site and a deficiency of 0.35 atoms in the M2 site. The ED patterns show rows of reflections that violate the reflection extinctions for Bbmm, and which are due to a local ordering of Fe3 þ and vacancies in the M3 sites. Based on the ED results, a model was developed in space group Pnma, in which planes containing corner-shared octahedral dimers of M3 atoms are ordered on a scale of ∼6 nm. The Pnma model was refined successfully against the synchrotron single-crystal data. Non-stoichiometry can be explained within the Pnma local-order model by distortions at the M3 sites in non-stoichiometric regions, where local, barbosalite-like, trimeric chains of face-sharing octahedra are formed.

AB - A non-stoichiometric frondelite from the Hagendorf Süd pegmatite, Bavaria, has been studied using chemical and thermal analyses, electron diffraction (ED), Mössbauer spectroscopy and synchrotron single-crystal structure analysis. The structural formula, with occupancies of the M1, M2 and M3 sites given in sequence, is (Fe3 +)(Mn2 + 0.67Zn0.20Fe2 + 0.08Fe3 + 0.70)S 1.65(Fe3 + 2.30) (PO4)3(OH)4.9(H2O)0.1. The non-stoichiometric frondelite contains an excess of 0.3 atoms in the M3 site and a deficiency of 0.35 atoms in the M2 site. The ED patterns show rows of reflections that violate the reflection extinctions for Bbmm, and which are due to a local ordering of Fe3 þ and vacancies in the M3 sites. Based on the ED results, a model was developed in space group Pnma, in which planes containing corner-shared octahedral dimers of M3 atoms are ordered on a scale of ∼6 nm. The Pnma model was refined successfully against the synchrotron single-crystal data. Non-stoichiometry can be explained within the Pnma local-order model by distortions at the M3 sites in non-stoichiometric regions, where local, barbosalite-like, trimeric chains of face-sharing octahedra are formed.

KW - Crystal structure

KW - Electron diffraction

KW - Frondelite

KW - Local order

KW - Mössbauer spectra

KW - Non-stoichiometry

KW - Thermal analyses

UR - http://www.scopus.com/inward/record.url?scp=85055442002&partnerID=8YFLogxK

U2 - 10.1127/ejm/2018/0030-2734

DO - 10.1127/ejm/2018/0030-2734

M3 - Article

VL - 30

SP - 773

EP - 783

JO - European Journal of Mineralogy

JF - European Journal of Mineralogy

SN - 0935-1221

IS - 4

ER -