File:Rhomboedrique D51.svg

Cristal diatomique rhomboédrique (type α-Al₂O₃, α-Fe₂O₃). Groupe d'espace : ${\displaystyle \mathrm {R{\bar {3}}c} }$ (167), notation Strukturbericht : D5₁.

Le motif se compose de deux hexaèdres A₂B₃ (chaque hexaèdre est fait de deux tétraèdres non-réguliers tête-bêche), les atomes A occupant les sommets hauts et bas, et les atomes B occupant les sommets du triangle. Les hexaèdres symétriques par rapport au centre du motif. La distance entre les plans d'atomes B est la moitié de la grande diagonale c du rhomboèdre.

Diatomic rhombohedral crystal (e.g. α-Al₂O₃, α-Fe₂O₃). Space group: ${\displaystyle \mathrm {R{\bar {3}}c} }$ (167), Strukturbericht notation: D5₁.

The motto is made of two A₂B₃ hexahedrons (each hexaherdon is made of two non-regular tetrahedrons upside down); the A atoms are at the top and at the bottom, and the B atoms are at the summits of the triangle. One hexahedron is the central symetry of the other through the center of the motto. The distance between the planes containing the B atoms is the half of the great diagonal c of the rhombohedron.

Réalisé avec/made with: Inkscape

Voir aussi/see also

• Image:Rhomboedrique D51 2.svg
• Image:Corindon structure cristalline.svg

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