Activity III.C |

Build a model of the seventy-atom fullerene in which there are no contiguous pentagons. A model of C can be constructed from the C model by separating C in halves and then inserting a ring of ten additional atoms. The result is a football-shaped molecule. Consider the following questions while inspecting your model.

- How many five- and six-membered rings are there
in C?

**Answer: twelve 5's and twenty-five 6's.** - How many different kinds of vertices are there?

**Answer: five.** - How many of each kind of vertex are there?

**Answer: The five kinds of vertices are present in a ratio of 10:10:20:20:10.** - How many edges are there?

**Answer: 105.** - How many different kinds of edges are there?

**Answer: eight. There are four types of 6-6 ring fusions and four types of 6-5 ring fusions.** - How many 6-6 ring fusions and 6-5 ring fusions are there?

**Answer: 45 of the 6-6 variety and 60 of the 6-5 type.** - Given that the average edge is approximately 1.4 Å long, estimate the size of the cavity
(length and width).

**Answer: Length is ~ 7.6 Å and width is ~ 6.4 Å.**