Aristotype crystal structure and crystallographic distortions in Ia3¯d leucite/pollucite-structured phases

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Marco E. Ciriotti
Messaggi: 25569
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Aristotype crystal structure and crystallographic distortions in Ia3¯d leucite/pollucite-structured phases

Messaggio da Marco E. Ciriotti » mar 19 feb, 2019 12:17

Prossima pubblicazione.

Referenza:
▪ Knight, K.S. & Henderson, C.M.B. (2019): Defining an aristotype crystal structure and crystallographic distortions in leucite/pollucite-structured phases with space group Iad. Physics and Chemistry of Minerals, 46, (in press).

Abstract:
A universal aristotype crystal structure for leucite/pollucite-structured phases (A2B2IIIC4IVO12, A2BIIC5IVO12) with space group Iad has been determined by a non-linear optimisation of the fractional coordinates. The resultant T-site tetrahedron exhibits close to perfect 4¯3m point group symmetry (quadratic elongation 1.0000124, tetrahedral angle variance 1.53 × 10−5 degrees2). For any distorted leucite/pollucite crystal structure, an associated aristotype phase can be derived from the optimised fractional coordinates, with the aristotype phase lattice parameter calculated from the volume of the hettotype T-site tetrahedron. Assuming the aristotype T-site tetrahedron to be ideal, the distortion of the hettotype tetrahedron from that of the aristotype is described as the linear sum of the amplitudes of an appropriate set of symmetry-adapted basis-vectors of the effective regular TO4 molecule consistent with the observed point group symmetry within the crystal structure. The methodology is illustrated by reference to the disordered T-site, leucite-structured phase K2MgSi5O12.
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: 25569
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Aristotype crystal structure and crystallographic distortions in Ia3¯d leucite/pollucite-structured phases

Messaggio da Marco E. Ciriotti » mar 21 mag, 2019 10:29

Pubblicazione effettuata.

Referenza:
▪ Knight, K.S. & Henderson, C.M.B. (2019): Defining an aristotype crystal structure and crystallographic distortions in leucite/pollucite-structured phases with space group Ia3¯d. Physics and Chemistry of Minerals, 46, 595–605.
Marco E. Ciriotti

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

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