The document discusses the history and structures of benzene. In the 19th century, scientists proposed various structures for benzene including those suggested by Ladenburg, Dewar, benzvalene, and 3,3'-bicyclopropenyl. However, problems were identified with the structure proposed by Kekulé in 1861 which depicted benzene as alternating single and double bonds between the carbon atoms. The key aromatic structural features of benzene that were later established include the connectivity of adjacent 2p orbitals in a fully conjugated system that results in the molecule being almost flat.

1. Aromatic chemistry
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2. Benzene
Structures

3. Tetravalent
Carbon
19th century

4. (CH)6 19th century
Known Formula
Unknown Structure

5. What are
the possible
structures?

6. Ladenburg

7. Dewar

8. Benzvalene

9. 3,3’-Bicyclopropenyl

10. Loschmidt 1861

11. ne
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