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Tetrahedral Group


TetrahedralGroupTdTable

The tetrahedral group T_d is the point group of symmetries of the tetrahedron including the inversion operation. It is one of the 12 non-Abelian groups of order 24. The tetrahedral group has conjugacy classes 1, 8C_3, 3C_2, 6S_4, and 6sigma_d (Cotton 1990, pp. 47 and 434). Its multiplication table is illustrated above. The tetrahedral group T_d is implemented in the Wolfram Language as FiniteGroupData["Tetrahedral", "PermutationGroupRepresentation"] and as a point group as FiniteGroupData[{"CrystallographicPointGroup", "Td"}, "PermutationGroupRepresentation"].

TetrahedralGroupTTable

T_d has a pure rotational subgroup of order 12 denoted T (Cotton 1990, pp. 50 and 433). It is isomorphic to the alternating group A_4 and has conjugacy classes 1, 4C_3, 4C_3^2, and 3C_2. It has 10 subgroups: one of length 1, three of length 2, 4 of length 3, one of length 4, and one of length 12. Of these, only the trivial subgroup, subgroup of order 4, and complete subgroup are normal. The pure rotational tetrahedral subgroup T is implemented in the Wolfram Language as a point group as FiniteGroupData[{"CrystallographicPointGroup", "T"}, "PermutationGroupRepresentation"].

TetrahedralGroupTCycleGraph

The cycle graph of T is illustrated above. The numbers of elements A such that A^k=1 for k=1, 2, ..., 12, are 1, 4, 9, 4, 1, 12, 1, 4, 9, 4, 1, 12.

TetrahedralGroupTPolyhedra

Platonic and Archimedean solids that can be generated by group T are illustrated above, with the corresponding basis vector summarized in the following table, where phi is the golden ratio.

There is also a point group known as T_h. It has conjugacy classes 1, 4C_3, 4C_3^2, 3C_2, i, 4S_6, 4S_6^5, and 3sigma_h (Cotton 1990, pp. 50 and 434). The group T_h is implemented in the Wolfram Language as a point group as FiniteGroupData[{"CrystallographicPointGroup", "Th"}, "PermutationGroupRepresentation"].


See also

Finite Group T, Icosahedral Group, Octahedral Group, Point Groups, Polyhedral Group, Tetrahedron

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References

Cotton, F. A. Chemical Applications of Group Theory, 3rd ed. New York: Wiley, p. 47, 1990.Coxeter, H. S. M. "The Polyhedral Groups." §3.5 in Regular Polytopes, 3rd ed. New York: Dover, pp. 46-47, 1973.Lomont, J. S. "Icosahedral Group." §3.10.C in Applications of Finite Groups. New York: Dover, p. 81, 1987.

Cite this as:

Weisstein, Eric W. "Tetrahedral Group." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TetrahedralGroup.html

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