Buckyballs and Nanotubes

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Borospherene

A molecule containing 60 carbon atoms in a cage-like spherical shape was first produced in 1985 and was called buckminsterfullerene, or bucky-ball. The structure is like a soccer ball, made up of 20 hexagons and 12 pentagons.
A bucky-ball is shown on the right. Each blue sphere represents a carbon atom, and each cream-coloured line represents a covalent bond between 2 carbon atoms.
One of the reasons that scientists are very interested in buckminsterfullerene is because of its ability to hold atoms of different elements inside the cage-like structure. This could enable bucky-balls to be used to deliver drugs in the body, or to store atoms such as hydrogen.

In 1991, scientists discovered that carbon atoms can also form nanotubes, and in 2004, sheets of carbon atoms just 1 atom thick known as graphene were discovered.

But can atoms other than carbon make these kinds of 3-dimensional networks at the nanometre level?

Researchers from Brown University, Shanxi University and Tsinghua University in China have shown that a cluster of 40 boron atoms forms a hollow molecular cage similar to a carbon buckyball. It's the first experimental evidence that a boron cage structure does indeed exist.
This boron cage, called borospherene, isn't quite as spherical as its carbon cousin. Rather than a series of five- and six-membered rings formed by carbon, borospherene consists of 48 triangles, 4 seven-sided rings and 2 six-membered rings. Several atoms stick out a bit from the others, making the surface of borospherene somewhat less smooth than a buckyball.

Because of the electron deficiency of boron, borospherene is likely to bond well with hydrogen. So these tiny boron cages could serve as safe houses for hydrogen molecules.

Reference:
Brown University. "Researchers discover boron 'buckyball'." ScienceDaily. ScienceDaily, 13 July 2014. .

Further Reading:
Graphene
Molecular Formula
Allotropes

Suggested Study Questions:

1. Write the molecular formula for buckminsterfullerene given the information in the article above.
2. How many covalent bonds does each carbon atom in buckminsterfullerene make?
3. Do you expect buckminsterfullerene to be soluble or insoluble in water? Explain your answer.
4. Draw a representation of graphene.
5. How many covalent bonds does each carbon atom make in graphene?
6. Do you expect graphene to conduct electricity? Explain your answer.
7. Write the molecular formula for borospherene based on the information provided in the article.
8. In the pictorial representation of borospherene given above, what do each of the following represent:
   • red spheres
   • yellow lines
9. In what ways are the structures of bucky-balls and borospherene similar?
10. In what ways are the structures of bucky-balls and borospherene different?

Buckyballs in Space

In 1970, Japanese professor Eiji Osawa predicted the existence of buckyballs.
In 1985, Buckminster Fullerenes were first observed in the laboratory.
In 1996, Sir Harry Kroto, Bob Curl and Rick Smalley shared the Nobel Prize in chemistry for the discovery of buckyballs.
They were named after the architect Buckminster Fuller because they resemble his geodesic domes which have interlocking circles on the surface of a partial sphere. Buckyballs, 60 carbon atoms arranged into a three-dimensional spherical structure resembling a soccer ball, are allotropes of carbon.
Buckyballs have been found on Earth in candle soot, layers of rock and meteorites.

Astronomers using NASA's Spitzer Space Telescope have now discovered buckyballs in space, in a planetary nebula named Tc 1. Planetary nebula are the remains of stars that shed their outer layers of gas and dust as they age. A compact, hot star, or white dwarf, at the centre of the nebula illuminates and heats these clouds of discarded material. The buckyballs were found in these clouds when the astronomers used Spitzer's spectroscopy instrument to analyze infrared light from the planetary nebula and see the spectral signatures of the buckyballs. The data from Spitzer were compared with data from laboratory measurements of the same molecules and showed a perfect match.

Reference:
Jan Cami, Jeronimo Bernard-Salas, Els Peeters, and Sarah Elizabeth Malek. Detection of C₆₀ and C₇₀ in a Young Planetary Nebula. Science, 2010; DOI: 10.1126/science.1192035

Study Questions:

1. What is an allotrope?
2. Name two naturally occurring allotropes of carbon other than buckminster fullerenes.
3. In what ways are these allotropes above the same?
4. In what ways are these allotropes above different?
5. It has been suggested that buckyballs could be used in armour, drug delivery, and, superconductors. What do you think the physical and chemical properties of buckyballs are likely to be?
   
6. Name the other allotrope of oxygen besides (bi)molecular oxygen.
   
7. In what ways are the two allotropes of oxygen the same?
8. In what ways are the two allotropes of oxygen different?
9. There are several allotropes of phosphorus. Discuss the similarities and differences of these allotropes.