Huge molecules and polygon nomenclature

admin — Wed, 22 Apr 2009 23:03:19 +0000

This afternoon came to EPFL Prof. Achim Müller from University of Bielefeld (Germany) to give a talk to our institute. Among a series of impressive giant molybdenum-based spheres (see figure below) he mentioned molecules belonging to either Archimedean or Platonic solids… Although the talk itself was quite fascinating, the question I was asking to myself when leaving the auditorium was, what is the difference between these two types of polygons? Well, after a quick search, it turns out a Platonic solid is a regular polygon such as a tetrahedron, cube, octahedron, etc: they all have only one type of faces. On the other hand, an Archimedean solid is a semi-regular (or truncated) polygon. To this class belong truncated tetrahedrons, cuboctahedrons, or, probably more familiar to many readers, the famous buckyball (also known as football, or truncated icosahedron, or buckminsterfullerene), which possesses 12 pentagonal and 20 hexagonal faces.

And now, for people who would (should) be more interested in Prof. Müller’s work than in greek terminology, here are a couple of links to some of his most significant publications, mainly dealing with huge porous capsules, and therefore containing amazing pictures.

Spherical polyoxomolybdate based capsule. The 20 pores are occupied by guanidinium cations.

Angew. Chem. Int. Ed. 2004, 43, 4466-4470;
Angew. Chem. Int. Ed. 2003, 42, 2085-2090;
Angew. Chem. Int. Ed. 2003, 42, 5039-5044;
Angew. Chem. Int. Ed. 2002, 41, 3604-3609;
Angew. Chem. Int. Ed. Engl. 2000, 39, 1614-1616;

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Huge molecules and polygon nomenclature