+**D7d** is a discrete [Point Group](/wiki/Point_Group) in three dimensions, often encountered in crystallography and molecular symmetry. It describes a specific set of symmetry operations, featuring a seven-fold rotation axis perpendicular to a plane of reflection. This group, part of the larger family of [Dihedral Group](/wiki/Dihedral_Group)s, governs structures possessing high rotational symmetry combined with inversion elements.
+## See also
+- [Symmetry](/wiki/Symmetry)
+- [Group Theory](/wiki/Group_Theory)
+- [Crystal Structure](/wiki/Crystal_Structure)
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