Draw the structure of each compound.
(i) tropylium chloride
(j) sodium cyclopentadienide

Verified step by step guidance

1. Understand the chemical nature of each compound: (i) Tropylium chloride is a salt composed of the tropylium cation (C7H7+) and a chloride anion (Cl-). The tropylium cation is aromatic and has a planar, cyclic structure with 7 carbon atoms and a positive charge. (j) Sodium cyclopentadienide is a salt composed of the cyclopentadienide anion (C5H5-) and a sodium cation (Na+). The cyclopentadienide anion is aromatic and has a planar, cyclic structure with 5 carbon atoms and a negative charge.
2. For (i) Tropylium chloride: Draw a heptagonal (7-sided) ring to represent the tropylium cation. Place alternating double and single bonds around the ring to indicate aromaticity. Add a positive charge (+) inside or near the ring to represent the cation. Then, add a chloride ion (Cl-) nearby to complete the salt structure.
3. For (j) Sodium cyclopentadienide: Draw a pentagonal (5-sided) ring to represent the cyclopentadienide anion. Place alternating double and single bonds around the ring to indicate aromaticity. Add a negative charge (-) inside or near the ring to represent the anion. Then, add a sodium ion (Na+) nearby to complete the salt structure.
4. Ensure that the structures are drawn with proper bond angles and symmetry to reflect the aromatic nature of both the tropylium cation and the cyclopentadienide anion. Aromaticity is confirmed by the Huckel rule (4n+2 π electrons, where n is an integer).
5. Label each structure clearly as (i) Tropylium chloride and (j) Sodium cyclopentadienide to avoid confusion. Verify that the charges on the cation and anion balance out to form neutral salts in both cases.

Key Concepts

Tropylium Ion

The tropylium ion is a positively charged aromatic ion derived from toluene. It consists of a seven-membered carbon ring with a positive charge on one of the carbon atoms, making it a stable resonance structure. The aromatic nature of the ring contributes to its stability, allowing it to participate in various chemical reactions.

Cyclopentadiene

Cyclopentadiene is a five-membered cyclic compound with two double bonds. It is known for its ability to form a stable anion when deprotonated, which is crucial for understanding its reactivity. The cyclopentadienyl anion, formed from cyclopentadiene, is a key building block in organic synthesis and coordination chemistry.

Sodium Cyclopentadienide

Sodium cyclopentadienide is the sodium salt of the cyclopentadienyl anion, formed by deprotonating cyclopentadiene with sodium. This compound is a strong nucleophile and is often used in organic synthesis to form new carbon-carbon bonds. Its reactivity is largely due to the stability of the cyclopentadienyl anion, which can participate in various electrophilic substitution reactions.