Search: onr:"swepub:oai:DiVA.org:nrm-2495" >
Crystal-chemical as...
Crystal-chemical aspects of the roméite group, A2Sb2O6Y, of the pyrochlore supergroup
-
- Bosi, Ferdinando (author)
- Sapienza Università di Roma, Italy
-
- Christy, Andrew (author)
- Australian National University, Canberra, Australia
-
- Hålenius, Ulf (author)
- Naturhistoriska riksmuseet,Enheten för geovetenskap
-
(creator_code:org_t)
- 2018-01-26
- 2017
- English.
-
In: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 81:6, s. 1287-1302
- Related links:
-
https://urn.kb.se/re...
-
show more...
-
https://doi.org/10.1...
-
show less...
Abstract
Subject headings
Close
- Four specimens of the roméite-group minerals oxyplumboroméite and fluorcalcioroméite from the Långban Mn-Fe deposit in Central Sweden were structurally and chemically characterized by single-crystal X-ray diffraction, electron microprobe analysis and infrared spectroscopy. The data obtained and those on additional roméite samples from literature show that the main structural variations within the roméite group are related to variations in the content of Pb2+, which is incorporated into the roméite structure via the substitution Pb2+ → A2+ where A2+ = Ca, Mn and Sr. Additionally, the cation occupancy at the six-fold coordinated B site, which is associated with the heterovalent substitution BFe3+ + Y□ → BSb5+ + YO2–, can strongly affect structural parameters.Chemical formulae of the roméite minerals group are discussed. According to crystal-chemical information, the species associated with the name ‘kenoplumboroméite’, hydroxycalcioroméite and fluorcalcioroméite most closely approximate end-member compositions Pb2(SbFe3+)O6□, Ca2(Sb5+Ti)O6(OH) and (CaNa)Sb2O6F, respectively. However, in accord with pyrochlore nomenclature rules, their names correspond to multiple end-members and are best described by the general formulae: (Pb,#)2(Sb,#)2O6□, (Ca,#)2(Sb,#)2O6(OH) and (Ca,#)Sb2(O,#)6F, where ‘#’ indicates an unspecified charge-balancing chemical substituent, including vacancies.
Subject headings
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)
Keyword
- The changing Earth
- Den föränderliga jorden
Publication and Content Type
- ref (subject category)
- art (subject category)
Find in a library
To the university's database