Rectified 24-cell explained

bgcolor=#e7dcc3 align=center colspan=3Rectified 24-cell
bgcolor=#ffffff align=center colspan=3
Schlegel diagram
8 of 24 cuboctahedral cells shown
TypeUniform 4-polytope
Schläfli symbolsr =

\left\{\begin{array}{l}3\\4,3\end{array}\right\}


rr=

r\left\{\begin{array}{l}3\\3,4\end{array}\right\}


r =

r\left\{\begin{array}{l}3\\3\\3\end{array}\right\}

Coxeter diagrams

or
Cells48
Faces24096
144
Edges288
Vertices96
Vertex figure
Triangular prism
Symmetry groupsF4 [3,4,3], order 1152
B4 [3,3,4], order 384
D4 [3<sup>1,1,1</sup>], order 192
Propertiesconvex, edge-transitive
Uniform index22 23 24
In geometry, the rectified 24-cell or rectified icositetrachoron is a uniform 4-dimensional polytope (or uniform 4-polytope), which is bounded by 48 cells: 24 cubes, and 24 cuboctahedra. It can be obtained by rectification of the 24-cell, reducing its octahedral cells to cubes and cuboctahedra.

E. L. Elte identified it in 1912 as a semiregular polytope, labeling it as tC24.

It can also be considered a cantellated 16-cell with the lower symmetries B4 = [3,3,4]. B4 would lead to a bicoloring of the cuboctahedral cells into 8 and 16 each. It is also called a runcicantellated demitesseract in a D4 symmetry, giving 3 colors of cells, 8 for each.

Construction

The rectified 24-cell can be derived from the 24-cell by the process of rectification: the 24-cell is truncated at the midpoints. The vertices become cubes, while the octahedra become cuboctahedra.

Cartesian coordinates

A rectified 24-cell having an edge length of has vertices given by all permutations and sign permutations of the following Cartesian coordinates:

(0,1,1,2) [4!/2!×2<sup>3</sup> = 96 vertices]

The dual configuration with edge length 2 has all coordinate and sign permutations of:

(0,2,2,2) [4×2<sup>3</sup> = 32 vertices]

(1,1,1,3) [4×2<sup>4</sup> = 64 vertices]

Images

Stereographic projection

Center of stereographic projection
with 96 triangular faces blue

Symmetry constructions

There are three different symmetry constructions of this polytope. The lowest

{D}4

construction can be doubled into

{C}4

by adding a mirror that maps the bifurcating nodes onto each other.

{D}4

can be mapped up to

{F}4

symmetry by adding two mirror that map all three end nodes together.

The vertex figure is a triangular prism, containing two cubes and three cuboctahedra. The three symmetries can be seen with 3 colored cuboctahedra in the lowest

{D}4

construction, and two colors (1:2 ratio) in

{C}4

, and all identical cuboctahedra in

{F}4

.
Coxeter group

{F}4

= [3,4,3]

{C}4

= [4,3,3]

{D}4

= [3,3<sup>1,1</sup>]
Order1152384192
Full
symmetry
group
[3,4,3][4,3,3]<[3,3<sup>1,1</sup>]> = [4,3,3]
[3[3<sup>1,1,1</sup>]] = [3,4,3]
Coxeter diagram
Facets3:
2:
2,2:
2:
1,1,1:
2:
Vertex figure

Alternate names

Related polytopes

The convex hull of the rectified 24-cell and its dual (assuming that they are congruent) is a nonuniform polychoron composed of 192 cells: 48 cubes, 144 square antiprisms, and 192 vertices. Its vertex figure is a triangular bifrustum.

Related uniform polytopes

The rectified 24-cell can also be derived as a cantellated 16-cell:

References