Polyhedral Borane and Boron Exercises

Some of these questions make reference to the assigned papers by Grimes and by Hawthorne, so please make sure you have read them before attempting to answer the questions below.

1. What is the basic structural building block of elemental boron?
2. Examine the shapes of the 5f orbitals and identify which of these have the same symmetry properties as atomic p_x, p_y, and p_z orbitals.
3. Which of the 5f atomic orbitals do correspond to four of the occupied skeletal bonding MOs of [B₁₂H₁₂]^2- ?
4. Comment on the stability and toxicity of [B₁₂H₁₂]^2- salts.
5. What are the point group symmetries of the isomers of carborane C₂B₁₀H₁₂?
6. Sketch out the structure of the molecule Hg₄[C₂B₁₀H₁₀]₄. What family of molecules is this an example of and how do they function?
7. Describe the physical basis for BNCT.
8. Very weakly (or almost non-) coordinating anions can stabilize cations that otherwise are very unstable. What anion was used for stabilization of the first azafullerene?
9. For what application was B₁₀H₁₄ under study at the Army's Redstone arsenal?