beaded vase

Bang-Rui's mother knew my hobby of making beaded molecules. So she gave me a beautiful beaded vase she made. It is basically a pillar-shaped C₈₄ with the top surface removed.

Here is a bead model of pillar-shape C₈₄ I made before.

The other two smaller fullerenes in the same homologous series are C₆₀ and C₇₂.

Pillar-shaped C60 and related C72

There are 1812 isomers of C₆₀. Only the one with the shape of a soccer ball is stable enough and can be synthesized routinely. However, chemists in the Xiamen university have successfully created a few chlorinated isomers of C₆₀ three years ago. I will try to make bead models of them when I find time. Here I would like to show the bead model of another elusive isomer of C₆₀ with pillar shape (point group, D_6h) which might be found someday.

Of course, there is a whole series of pillar-shape fullerenes by simply inserting short rings of carbon nanotubes. Here is the bead model of C72, which is the second one in this series.

Endcapped nanotubes

I just finished writing the section on the influence of endcaps on the nanotube's shape in my "The beaded molecules I. Spheroids" paper. I put my emphasis on (5,5) and (9,0) SWNT with the C60 endcaps, which is fine. I thought there should be a more systematic study on the effect of endcaps from the beaded molecule's viewpoints. This should include the patching conditions, chiral nanotubes and the effect on the shape change. I have no doubt that many of the issues I raised here probably have been treated before. I still think it is worthy to do it with the beaded molecules.

The effect of endcaps on the shapes of nanotubes

Supprising results do occur every time I try to make a new type of beaded molecules. For instance, I didn't expect to find anything particular interesting about the endcaps of the nanotube. I have built two short nanotubes endcapped with C60 along the five-fold symmetry axis more than two months ago. I have also taken a few pictures for these molecules. Well, the result looks good, the tubes are just like perfect cylinders. This is probably because there is little difference between five-fold symmetry and perfect rotational symmetry around the central axis. The lower symmetry of endcaps does not seems to produce broken symmetry. Or may be the effect is too small to notice at first sight.

I made another tube also with C60 endcaps, but instead of along five-fold symmetry axis, this time I patch the tube with the three-fold symmetry axis. I was amazed by the broken symmtry of the nanotube induced by the three-fold endcaps. Since there are many possible ways to connect the tube with the endcaps, depending on the relative orientation of the two endcaps. I found that the resulting endcapped nanotube can be either achiral or chiral, even though the uncapped nanotube is achiral. I wonder whether other people have noticed these interesting situations or not?