Jinshajiangite: structure, twinning and pseudo­symmetry

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Marco E. Ciriotti
Messaggi: 24698
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Jinshajiangite: structure, twinning and pseudo­symmetry

Messaggio da Marco E. Ciriotti » ven 11 mag, 2018 9:34

Prossima pubblicazione.

Referenza:
▪ Jin, S., Xu, H., Lee, S., Fu, P. (2018): Jinshajiangite: structure, twinning and pseudo­symmetry. Acta Crystallographica, B74, (in press).

Abstract:
The crystal structure of jinshajiangite is revisited and corrected, with its pseudo-merohedral twinning and pseudosymmetry discussed in detail.
Marco E. Ciriotti

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

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Marco E. Ciriotti
Messaggi: 24698
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Jinshajiangite: structure, twinning and pseudo­symmetry

Messaggio da Marco E. Ciriotti » mar 26 giu, 2018 18:26

Referenza:
▪ Jin, S., Xu, H., Lee, S., Fu, P. (2018): Jinshajiangite: structure, twinning and pseudo­symmetry. Acta Crystallographica, B74, (in press).

Abstract:
The crystal structure of jinshajiangite based on a sample from its original discovery location is studied using single‐crystal X‐ray diffraction and transmission electron microscopy methods. Jinshajiangite is a titanium silicate mineral with an ideal chemical formula of BaNaFe4Ti2(Si2O7)2O2(OH)2F. The structure of jinshajiangite is of P-1 symmetry (triclinic system), with a = 8.7331 (2) Å, b = 8.7366 (2) Å, c = 11.0404 (3) Å, α = 81.477 (1)°, β = 110.184 (1)°, γ = 104.384 (1)° and V = 764.03 (3) Å3, instead of the previously proposed C-1 cell [a = 10.7059 (5) Å, b = 13.7992 (7) Å, c = 20.760 (1) Å, α = 90.008 (1)°, β = 94.972 (1)°, γ = 89.984 (1)°, V = 3055.4 (4) Å3]. The basic topology of the new structure is similar to the previously proposed C-1 structure, except there is only one type of titanium silicate and intermediate cation layer in the structure (instead of two types), which are all related by the translation along the c‐axis. Even though there is a significant amount of Mn in the chemical composition, no obvious ordering between Fe and Mn is observed in the structure. All the mineral species of the perraultite‐type structure (jinshajiangite, perraultite, surkhobite and bobshannonite) should have the same P-1 structure as jinshajiangite with ∼10 Å d001 spacing, and all the previously proposed monoclinic space groups were pseudosymmetry generated by nanoscale polysynthetic twinning on the (001) composition plane. The similar phenomenon observed in bafertisite is also discussed in the paper with an alternative polytype structure model proposed.
Marco E. Ciriotti

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

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Marco E. Ciriotti
Messaggi: 24698
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Jinshajiangite: structure, twinning and pseudo­symmetry

Messaggio da Marco E. Ciriotti » ven 03 ago, 2018 15:29

Pubblicazione effettuata.

Referenza:
▪ Jin, S., Xu, H., Lee, S., Fu, P. (2018): Jinshajiangite: structure, twinning and pseudo­symmetry. Acta Crystallographica, B74, 325-336.
Marco E. Ciriotti

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

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