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

Abstract

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.

Ordering Phase Transition with Symmetry-Breaking from Disorder over Non-Equivalent Sites: Calorimetric and Crystallographic Study of Crystalline d-Sorbose

“…The previous examples included testing a unified model for displacive and order-disorder transitions [27] in a clean (neat) system [28,29], systematic studies of the effects of well-defined impurities on such well-characterized systems [30,31], and the identification of a dipolar Ising system with an easily accessible transition temperature [32]. A new subject of the phase transition to exotic superstructures was also presented recently [33]. The present study is another example in the same spirit: molecular crystals offer typical systems for condensed matter physics because of the richness of their variety.…”