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4.5.3.17: Twinning by metric merohedry

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    Twinning by metric merohedry is a special case of twinning by merohedry which occurs when:

    • the lattice of the individual has accidentally a specialized metric which corresponds to a higher holohedry
    • the twin operation belongs to this higher holohedry only

    If H is the individual point group, D(H) the corresponding holohedry and D(L) the point group of the lattice, twinning by metric merohedry corresponds to D(L) ⊃ D(H) ⊇ H

    Twinning by metric merohedry can be seen as the degeneration of twinning by reticular merohedry to twin index 1, or of twinning by pseudomerohedry to twin obliquity zero.

    4.5.3.17: Twinning by metric merohedry is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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