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  2. Crystallographic point group - Wikipedia

    en.wikipedia.org/wiki/Crystallographic_point_group

    Many of the crystallographic point groups share the same internal structure. For example, the point groups 1, 2, and m contain different geometric symmetry operations, (inversion, rotation, and reflection, respectively) but all share the structure of the cyclic group C 2.

  3. Protomer - Wikipedia

    en.wikipedia.org/wiki/Protomer

    In structural biology, a protomer is the structural unit of an oligomeric protein. It is the smallest unit composed of at least one protein chain. The protomers associate to form a larger oligomer of two or more copies of this unit. Protomers usually arrange in cyclic symmetry to form closed point group symmetries.

  4. Point groups in three dimensions - Wikipedia

    en.wikipedia.org/wiki/Point_groups_in_three...

    The conjugacy definition would also allow a mirror image of the structure, but this is not needed, the structure itself is achiral. For example, if a symmetry group contains a 3-fold axis of rotation, it contains rotations in two opposite directions. (The structure is chiral for 11 pairs of space groups with a screw axis.)

  5. Cyclic symmetry in three dimensions - Wikipedia

    en.wikipedia.org/wiki/Cyclic_symmetry_in_three...

    It has reflection symmetry with respect to a plane perpendicular to the n-fold rotation axis. C nv, [n], (*nn) of order 2n - pyramidal symmetry or full acro-n-gonal group (abstract group Dih n); in biology C 2v is called biradial symmetry. For n=1 we have again C s (1*). It has vertical mirror planes. This is the symmetry group for a regular n ...

  6. Electrocyclic reaction - Wikipedia

    en.wikipedia.org/wiki/Electrocyclic_reaction

    According to the frontier molecular orbital theory, the sigma bond in the ring will open in such a way that the resulting p-orbitals will have the same symmetry as the HOMO of the product. [4] For the 5,6-dimethylcyclohexa-1,3-diene, only a disrotatory mode would result in p-orbitals having the same symmetry as the HOMO of hexatriene.

  7. Molecular symmetry - Wikipedia

    en.wikipedia.org/wiki/Molecular_symmetry

    In chemistry, molecular symmetry describes the symmetry present in molecules and the classification of these molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can be used to predict or explain many of a molecule's chemical properties , such as whether or not it has a dipole moment , as well ...

  8. Ring flip - Wikipedia

    en.wikipedia.org/wiki/Ring_flip

    The molecular motions involved in a chair flip are detailed in the figure on the right: The half-chair conformation (D, 10.8 kcal/mol, C 2 symmetry) is the energy maximum when proceeding from the chair conformer (A, 0 kcal/mol reference, D 3d symmetry) to the higher energy twist-boat conformer (B, 5.5 kcal/mol, D 2 symmetry).

  9. Circular symmetry - Wikipedia

    en.wikipedia.org/wiki/Circular_symmetry

    In geometry, circular symmetry is a type of continuous symmetry for a planar object that can be rotated by any arbitrary angle and map onto itself. Rotational circular symmetry is isomorphic with the circle group in the complex plane , or the special orthogonal group SO(2), and unitary group U(1).