Pyrosmalite-(Fe), Fe 8Si 6O 15(OH,Cl) 10

Hexiong Yang, Robert T Downs, Yongbo W. Yang, Warren H. Allen

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Pyrosmalite-(Fe), ideally Fe II 8Si 6O 15(OH,Cl) 10 [refined composition in this study: Fe 8Si 6O 15(OH 0.814Cl 0.186) 10·-0.45H 2O, octairon(II) hexasilicate deca(chloride/hydroxide) 0.45-hydrate], is a phyllosilicate mineral and a member of the pyrosmalite series (Fe,Mn) 8Si 6O 15(OH,Cl) 10, which includes pyrosmalite-(Mn), as well as friedelite and mcgillite, two polytypes of pyrosmalite-(Mn). This study presents the first structure determination of pyrosmalite-(Fe) based on singlecrystal X-ray diffraction data from a natural sample from Burguillos del Cerro, Badajos, Spain. Pyrosmalite-(Fe) is isotypic with pyrosmalite-(Mn) and its structure is characterized by a stacking of brucite-type layers of FeO 6-octahedra alternating with sheets of SiO 4 tetrahedra along [001]. These sheets consist of 12-, six-and four-membered rings of tetrahedra in a 1:2:3 ratio. In contrast to previous studies on pyrosmalite-(Mn), which all assumed that Cl and one of the four OH-groups occupy the same site, our data on pyrosmalite-(Fe) revealed a split-site structure model with Cl and OH occupying distinct sites. Furthermore, our study appears to suggest the presence of disordered structural water in pyrosmalite-(Fe), consistent with infrared spectroscopic data measured from the same sample. Weak hydrogen bonding between the ordered OH-groups that are part of the brucitetype layers and the terminal silicate O atoms is present.

Original languageEnglish (US)
JournalActa Crystallographica Section E: Structure Reports Online
Volume68
Issue number1
DOIs
StatePublished - Jan 2012

Fingerprint

Model structures
Hydrates
tetrahedrons
Silicates
Hydrogen bonds
Minerals
brucite
Infrared radiation
X ray diffraction
Atoms
Spain
Magnesium Hydroxide
Chemical analysis
hydrates
hydroxides
Water
silicates
chlorides
minerals
Chlorides

Keywords

  • Data-to-parameter ratio = 16.4
  • Disorder in main residue
  • H-atom completeness 83%
  • Mean σ(Fe-O) = 0.001 Å
  • R factor = 0.023
  • Single-crystal X-ray study
  • T = 293 K
  • wR factor = 0.068

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)
  • Chemistry(all)

Cite this

Pyrosmalite-(Fe), Fe 8Si 6O 15(OH,Cl) 10 . / Yang, Hexiong; Downs, Robert T; Yang, Yongbo W.; Allen, Warren H.

In: Acta Crystallographica Section E: Structure Reports Online, Vol. 68, No. 1, 01.2012.

Research output: Contribution to journalArticle

Yang, Hexiong ; Downs, Robert T ; Yang, Yongbo W. ; Allen, Warren H. / Pyrosmalite-(Fe), Fe 8Si 6O 15(OH,Cl) 10 In: Acta Crystallographica Section E: Structure Reports Online. 2012 ; Vol. 68, No. 1.
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abstract = "Pyrosmalite-(Fe), ideally Fe II 8Si 6O 15(OH,Cl) 10 [refined composition in this study: Fe 8Si 6O 15(OH 0.814Cl 0.186) 10·-0.45H 2O, octairon(II) hexasilicate deca(chloride/hydroxide) 0.45-hydrate], is a phyllosilicate mineral and a member of the pyrosmalite series (Fe,Mn) 8Si 6O 15(OH,Cl) 10, which includes pyrosmalite-(Mn), as well as friedelite and mcgillite, two polytypes of pyrosmalite-(Mn). This study presents the first structure determination of pyrosmalite-(Fe) based on singlecrystal X-ray diffraction data from a natural sample from Burguillos del Cerro, Badajos, Spain. Pyrosmalite-(Fe) is isotypic with pyrosmalite-(Mn) and its structure is characterized by a stacking of brucite-type layers of FeO 6-octahedra alternating with sheets of SiO 4 tetrahedra along [001]. These sheets consist of 12-, six-and four-membered rings of tetrahedra in a 1:2:3 ratio. In contrast to previous studies on pyrosmalite-(Mn), which all assumed that Cl and one of the four OH-groups occupy the same site, our data on pyrosmalite-(Fe) revealed a split-site structure model with Cl and OH occupying distinct sites. Furthermore, our study appears to suggest the presence of disordered structural water in pyrosmalite-(Fe), consistent with infrared spectroscopic data measured from the same sample. Weak hydrogen bonding between the ordered OH-groups that are part of the brucitetype layers and the terminal silicate O atoms is present.",
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T1 - Pyrosmalite-(Fe), Fe 8Si 6O 15(OH,Cl) 10

AU - Yang, Hexiong

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AU - Yang, Yongbo W.

AU - Allen, Warren H.

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N2 - Pyrosmalite-(Fe), ideally Fe II 8Si 6O 15(OH,Cl) 10 [refined composition in this study: Fe 8Si 6O 15(OH 0.814Cl 0.186) 10·-0.45H 2O, octairon(II) hexasilicate deca(chloride/hydroxide) 0.45-hydrate], is a phyllosilicate mineral and a member of the pyrosmalite series (Fe,Mn) 8Si 6O 15(OH,Cl) 10, which includes pyrosmalite-(Mn), as well as friedelite and mcgillite, two polytypes of pyrosmalite-(Mn). This study presents the first structure determination of pyrosmalite-(Fe) based on singlecrystal X-ray diffraction data from a natural sample from Burguillos del Cerro, Badajos, Spain. Pyrosmalite-(Fe) is isotypic with pyrosmalite-(Mn) and its structure is characterized by a stacking of brucite-type layers of FeO 6-octahedra alternating with sheets of SiO 4 tetrahedra along [001]. These sheets consist of 12-, six-and four-membered rings of tetrahedra in a 1:2:3 ratio. In contrast to previous studies on pyrosmalite-(Mn), which all assumed that Cl and one of the four OH-groups occupy the same site, our data on pyrosmalite-(Fe) revealed a split-site structure model with Cl and OH occupying distinct sites. Furthermore, our study appears to suggest the presence of disordered structural water in pyrosmalite-(Fe), consistent with infrared spectroscopic data measured from the same sample. Weak hydrogen bonding between the ordered OH-groups that are part of the brucitetype layers and the terminal silicate O atoms is present.

AB - Pyrosmalite-(Fe), ideally Fe II 8Si 6O 15(OH,Cl) 10 [refined composition in this study: Fe 8Si 6O 15(OH 0.814Cl 0.186) 10·-0.45H 2O, octairon(II) hexasilicate deca(chloride/hydroxide) 0.45-hydrate], is a phyllosilicate mineral and a member of the pyrosmalite series (Fe,Mn) 8Si 6O 15(OH,Cl) 10, which includes pyrosmalite-(Mn), as well as friedelite and mcgillite, two polytypes of pyrosmalite-(Mn). This study presents the first structure determination of pyrosmalite-(Fe) based on singlecrystal X-ray diffraction data from a natural sample from Burguillos del Cerro, Badajos, Spain. Pyrosmalite-(Fe) is isotypic with pyrosmalite-(Mn) and its structure is characterized by a stacking of brucite-type layers of FeO 6-octahedra alternating with sheets of SiO 4 tetrahedra along [001]. These sheets consist of 12-, six-and four-membered rings of tetrahedra in a 1:2:3 ratio. In contrast to previous studies on pyrosmalite-(Mn), which all assumed that Cl and one of the four OH-groups occupy the same site, our data on pyrosmalite-(Fe) revealed a split-site structure model with Cl and OH occupying distinct sites. Furthermore, our study appears to suggest the presence of disordered structural water in pyrosmalite-(Fe), consistent with infrared spectroscopic data measured from the same sample. Weak hydrogen bonding between the ordered OH-groups that are part of the brucitetype layers and the terminal silicate O atoms is present.

KW - Data-to-parameter ratio = 16.4

KW - Disorder in main residue

KW - H-atom completeness 83%

KW - Mean σ(Fe-O) = 0.001 Å

KW - R factor = 0.023

KW - Single-crystal X-ray study

KW - T = 293 K

KW - wR factor = 0.068

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DO - 10.1107/S1600536811052822

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