Chemographic exploration of the hyalotekite structure-type

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Marco E. Ciriotti
Messaggi: 24899
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Chemographic exploration of the hyalotekite structure-type

Messaggio da Marco E. Ciriotti » lun 27 nov, 2017 8:35

Referenza:
▪ Hawthorne, F.C., Sokolova, E., Agakhanov, A.A., Pautov, L.A., Karpenko, V.Yu., Grew, E.S. (2018): Chemographic exploration of the hyalotekite structure-type. Mineralogical Magazine, 82, (in press).

Abstract:
We explore the possible end-member compositions within this group by conflating the properties of an end member with the stoichiometry imposed by the bond topology of the hyalotekite structure-type and the crystal-chemical properties of its known constituents. There are two high-coordination sites in the hyalotekite structure, A and B, and occupancy of each of these sites can be determined only by crystal-structure refinement. If these two sites are considered together, there are 19 end-member compositions of the triclinic structure and 6 end-member compositions of the tetragonal structure involving A,B = Ba2+, Pb2+, K+; M = Ca2+, Y3+, REE3+; T = Si4+, B3+, Be2+. There is the possibility for many other hyalotekite-group minerals, and two potential new minerals have been identified from data in the literature.


NdR: Al momento i minerali del Hyalotekite group sono i seguenti:
Hyalotekite Ba4Ca2[B2(BSi)Si8O28]F
Itsiite Ba4Ca2[B2B2Si8O28]□
Kapitsaite-(Y) Ba4(YCa)[B2B2Si8O28]F
Khvorovite Pb2+4Ca2[B2(BSi)Si8O28]F
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 24899
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Chemographic exploration of the hyalotekite structure-type

Messaggio da Marco E. Ciriotti » ven 26 ott, 2018 10:13

Pubblicazione effettuata.

Referenza:
▪ Hawthorne, F.C., Sokolova, E., Agakhanov, A.A., Pautov, L.A., Karpenko, V.Yu., Grew, E.S. (2018): Chemographic exploration of the hyalotekite structure-type. Mineralogical Magazine, 82, 929-937.

Abstract:
The hyalotekite group has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (memorandum 57–SM/16). The general formula of the minerals of the hyalotekite group may be written as: A2B2M2[Si8T4O28]W where A = Ba2+, Pb2+ or K+; B = Ba2+, Pb2+ or K+; M = Ca2+, Y3+ or REE3+; T = Si4+, B3+ or Be2+; and W = F– or □ (where REE = rare-earth elements and □ = vacancy).
Four minerals are currently known in this group: hyalotekite, Ba4Ca2[Si8B2(SiB)O28]F, triclinic, I-1; khvorovite, Pb2+4Ca2[Si8B2(SiB)O28]F, triclinic I-1; kapitsaite-(Y), Ba4(YCa)[Si8B2B2O28]F, triclinic, I-1; and itsiite Ba4Ca2[Si8B4O28]□, tetragonal, I-42m.
We explore the possible end-member compositions within this group by conflating the properties of an end-member with the stoichiometry imposed by the bond topology of the hyalotekite structure-type and the crystal-chemical properties of its known constituents. There are two high-coordination sites in the hyalotekite structure, A and B, and occupancy of each of these sites can be determined only by crystal-structure refinement. If these two sites are considered together, there are 19 end-member compositions of the triclinic structure and six end-member compositions of the tetragonal structure involving A and B = Ba2+, Pb2+, K+; M = Ca2+, Y3+, REE3+; and T = Si4+, B3+, Be2+. There is the possibility for many other hyalotekite-group minerals, and two potential new minerals have been identified from data in the literature.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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