Cell-quintupling: Structural phase transition in a molecular crystal, bis(trans-4-butylcyclohexyl)methanol.

A structural phase transition at 151.6 K of the title compound [bis(trans-4-butylcyclohexyl)methanol] is examined by X-ray diffraction crystallography, Fourier-transform infrared spectroscopy, and adiabatic calorimetry. A general consideration on possible superstructures indicates that a single modulation wave is sufficient to drive this cell-quintupling transition. The entropy of transition determined calorimetrically indicates that two conformations are dominant in the room-temperature phase in contrast to the fivefold disorder expected from the structure of the low-temperature phase.