![](https://coimages.sciencemuseumgroup.org.uk/23/187/large_thumbnail_1977_0164__0003_.jpg)
Graebe's model of space formulae for Benzene
![Model of space formulae for Benzene, Graebe's formulae](https://coimages.sciencemuseumgroup.org.uk/330/127/small_thumbnail_smg00047410.jpg)
![Model of space formulae for Benzene, Graebe's formulae](https://coimages.sciencemuseumgroup.org.uk/282/605/small_thumbnail_1924_0564__0002_.jpg)
![Model of space formulae for Benzene, Graebe's formulae](https://coimages.sciencemuseumgroup.org.uk/282/604/small_thumbnail_1924_0564__0001_.jpg)
Model of space formulae for Benzene, Graebe's formulae
These models were designed to illustrate some of the structures that were proposed for benzene prior to modern molecular orbital theories.
This represents Kekule’s plane formula with alternating single (corners touching) and double (edges touching) bonds between the carbon atoms.