The structure of tetraborane(10) is shown below. The B–H terminal bonds are shorter than the B–H bridge bonds. Explain why.

• A. The B–H bridge bonds are longer than the terminal B–H bonds because they are weaker electron-deficient bonds.
• B. The B–H bridge bonds are longer than the terminal B–H bonds because they have greater electron density and experience greater repulsion.
• C. The B–H bridge bonds are longer than the terminal B–H bonds because they are ordinary covalent bonds.
• D. The B–H bridge bonds are longer than the terminal B–H bonds because they have lesser electron density and experience greater repulsion.

Answer: (A)