Chia-Chin Tsoo & Bih-Yaw Jin

Research Fellow & Professor
National Center for High-Performance Computing, National Applied Research Laboratories & Department of Chemistry, National Taiwan University
Hsinchu, Taiwan & Taipei, Taiwan

Zeolite, a family of aluminosilicate minerals based on the TO4 tetrahedral units, where T is an aluminum or silicon cation and O is an oxygen anion, provides a best example of the minimum inventory/maximum diversity systems of Peter Pearce. A rich variety of zeolite structures can be thought to consist of a few polyhedral building units, such as truncated octahedra, prisms, and dodecahedra, which again are made up of vertex-linked tetrahedra with oxygen anions located at vertices. Here, we show that the mathematical beading can be used to construct the hard-sphere open packing models of these zeolite structures, in which spherical beads represent oxygen anions; while smaller cations hidden inside the tetrahedra are not shown in the model.

Bead model of Sodalite structure
20 x 20 x 20 cm
17mm Wooden beads

Sodalite structure can be thought to consist of the space filling tessellation of truncated octahedra, also known as the bitruncated cubic honeycomb, or the Kelvin structure.

Bead model of Zeolite A structure
18 x 18 x 18 cm
10mm plastic beads

Zeolite A can be viewed as a space filling tessellation of cubes, truncated octahedra, and truncated cuboctahedra, also known as the cantitruncated cubic honeycomb.