Twinning of tetrahedrite — OD approach

[Marco E. Ciriotti]

Referenza:
▪ Makovicky, E. (2021): Twinning of Tetrahedrite—OD Approach. Minerals, 11, 170.

Abstract:
The common twinning of tetrahedrite and tennantite can be described as an order–disorder (OD) phenomenon. The unit OD layer is a one-tetrahedron-thick (111) layer composed of six-member rings of tetrahedra, with gaps between them filled with Sb(As) coordination pyramids and triangular-coordinated (Cu, Ag). The stacking sequence of six-member rings is ABCABC, which can also be expressed as a sequence of three consecutive tetrahedron configurations, named α, β, and γ. When the orientation of component tetrahedra is uniform, the α, β, γ, α sequence builds the familiar cage structure of tetrahedrite. However, when the tetrahedra of the β layer are rotated by 180° against those in the underlying α configurations and/or when a rotated α configuration follows after the β configuration (instead of γ), twinning is generated. If repeated, this could generate the ABAB sequence which would modify the structure considerably. If the rest of the structure grows as a regular cubic tetrahedrite structure, the single occurrence of the described defect sequences creates a twin.

[Ferdinando Giovine]

Buonasera, hai il pdf?
Grazie.
Ferd

[Massimo Russo]

Minerals è una rivista free on line.

Massimo

[Marco E. Ciriotti]

Si può accedere al sito di Crystals e Minerals e scaricare gratuitamente tutti i lavori che interessano.
Minerals e Crystals sono riviste open source free.

Ecco i link:
https://www.mdpi.com/2075-163X/11/2
https://www.mdpi.com/2073-4352/11/2