Frequently Asked Question

Group 13 elements, also known as the boron group, exhibit a wide range of hydrides, halides, and organometallic compounds. Here's a breakdown with potential tricky questions:
Hydrides:
Boranes: These are electron-deficient compounds with complex bonding like B2H6 (diborane).

Tricky question: Why are boranes electron deficient? (Hint: Consider the number of valence electrons available compared to the number required for typical covalent bonding.)
Aluminohydrides: LiAlH4 (lithium aluminum hydride) is a powerful reducing agent.

Tricky question: How does the structure of AlH4- differ from that of BH4-? (Hint: Consider the relative electronegativities of aluminum and boron.)
Halides:
Trihalides: Common examples include BF3, AlCl3, and GaBr3. These are Lewis acids.

Tricky question: Why are these trihalides strong Lewis acids? (Hint: Consider their electron configuration and the ability to accept electron pairs.)
Pentahalides: Examples include AlCl5 and GaBr5. These are often more complex with variable coordination numbers.

Tricky question: How do the structures of pentahalides differ from trihalides? (Hint: Consider the involvement of d orbitals in the heavier elements.)
Organometallic Compounds:
Alkyl and aryl derivatives: These are widely used in organic synthesis.

Tricky question: Why are organometallic compounds of group 13 elements often air-sensitive? (Hint: Consider the reactivity of the metal-carbon bond.)
General Tricky Questions:
Explain the trend in the stability of hydrides down Group 13.
Discuss the importance of the +3 oxidation state in Group 13 chemistry.
How do the bonding properties of boron differ from the heavier members of the group? (Hint: Consider the role of empty p-orbitals in boron.)