Fundamentals of Nanoscience I 635 100

Lab 7Fullerenes and Carbon Nanotubes20 pointsName:

Equipment: Molecular models, Transparencies

Description

In this lab we will build molecular models of Buckminster fullerene and carbon nanotubes.

Part 1 Fullerenes

Obtain a transparency and a 60 sp2 molecular model pieces (30 with 2 “plugs” and one “socket” and 30 with 2 “sockets” and one “plug”)

Arrange the pieces into the shape of a pentagon:

Next add a hexagon on each side of the pentagon:

Add a pentagon in each of the concave corners and continue building until the soccer ball shaped C60 is obtained:

  1. How many pentagons are in this structure?
  1. How many hexagons are in this structure?
  1. Are the five membered rings isolated or contiguous?
  1. Given that each edge (carbon-carbon bond length) is 1.44 Å long estimate the diameter and volume of the cavity.

Construct C70. You can start with C60 and add a ring of hexagons around the middle.

  1. How many pentagons are in this structure?
  1. How many hexagons are in this structure?
  1. Estimate the length and width of this structure given an average edge (bond length) of 1.44Å.

Part 2 Carbon Nanotubes

Obtain a piece of transparency paper patterned with hexagons.

In one corner of the sheet mark one of the corners of the hexagons with a magic marker. Take this to be the origin (0,0).

Identify and circle a (10,0) coordinate. Roll the foil so that the (10,0) coordinate is on top of the (0,0) coordinate. Make sure that all of the overlapping hexagons are coincident.

  1. Make a sketch which indicates the orientation of the hexagons with respect to the CNT axis.
  1. Would this be considered armchair, zigzag or chiral?

Identify a (5,5) coordinate. There are a couple of different ways of marking this. One is by moving parallel to the edge of the foil. The other is diagonal to the edge of the paper. One direction is easier to roll the foil. Mark this coordinate with a magic marker. Roll the foil to form a (5,5) carbon nanotube.

  1. Make a sketch which indicates the orientation of the hexagons with respect to the CNT axis.
  1. Would this be considered armchair, zigzag or chiral?

Try to construct a chiral nanotube.

Part 3More Carbon Nanotubes

Go back to the molecular model pieces. Construct a flat sheet of hexagons. Construct a large enough sheet to make a (5,5) carbon nanotube. Roll the tube into a (5,5) carbon nanotube. Close the ends of this tube by adding pentagons.

  1. How many pentagons are in this structure?

Make a (10,0) carbon nanotube.

Try to make a chiral carbon nanotube. Hint: See the picture below.

  1. Identify the following structures as armchair, zigzag or chiral.