Answer
Identifying the Counterion in (CH₃)₃CLi
In the compound (CH₃)₃CLi, also known as tert-butyl lithium, we are dealing with an organolithium compound. These compounds are ionic in nature, where the metal (lithium) forms an ionic bond with a carbon-based anion.
🔬 Understanding the Molecular Structure
The structure of (CH₃)₃CLi can be broken down into:
- (CH₃)₃C⁻ — the tert-butyl anion (a carbanion)
- Li⁺ — the lithium cation, which serves as the counterion
The carbanion (CH₃)₃C⁻ is stabilized due to the inductive effects of the three methyl groups. Lithium, being electropositive, stabilizes this anionic species by acting as the counterion.
📘 Key Concept
A counterion is the ion that accompanies an ionic species to maintain electrical neutrality. In this case:
- The organic part (CH₃)₃C⁻ is negatively charged.
- To balance the negative charge, the lithium ion (Li⁺) serves as the counterion.
Lithium ion is the counterion in (CH₃)₃CLi.
🧪 Final Notes
Organolithium compounds like tert-butyl lithium are widely used in organic synthesis, especially as strong bases or nucleophiles. Knowing the correct identity of their counterions is essential for understanding their reactivity and handling in lab environments.