The first suggestion of two forms for (strainless) cyclohexane goes as far back as H. Sachse, Chem. Ber., 1890, 23, 1363 and Z. Physik. Chem., 1892, 10, 203. This is nicely explained here. E. Mohr, J. Prakt. Chem., 1918, 98, 315 and Chem. Ber., 1922, 55, 230, translated Sachse's argument into a pictorial one. For more detail, see the second year modelling workshop
| Cyclohexane flat (six eclipsing C-C interactions): 130 kJ | Cyclohexane chair (six staggered C-C interactions): 28 kJ |
|---|---|
| Cyclohexane boat (four staggered/ two eclipsing C-C interactions): 54 kJ A transition state for twist boat interconversion |
Cyclohexane twist-boat (two
staggered/ four half-staggered C-C interactions): 50 kJ |
| Transition state for chair-chair interconversion (pseudorotation) | |