Monday, July 14, 2014

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?

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