Polymorphism of Cyclopentanol:  Crystallographic Characterization of the Ordered and Disordered Phases

Abstract

The polymorphism of cyclopentanol (C5H10O) has been further investigated by X-ray powder diffraction experiments and it has been found to agree with the most recent thermodynamic study [J. Chem. Thermodyn. 1995, 27, 953]. In addition to the previously reported orientationally disordered hexagonal phases I and II, the lattice symmetry of the low-temperature ordered phases III and IV have been determined by means of pattern-matching analyses both as monoclinic with Z = 24 (Cc and C2/c, respectively). The patterns revealed no significant differences between phases III and IV and the transition between both phases was found through careful determination of the variation of the lattice parameters as a function of the temperature. The strength of intermolecular interactions as well as the anisotropy in the solid phases has been analyzed by the study of the isobaric thermal-expansion tensor and the results are discussed in the light of previously reported literature covering dynamics disorder.

Effects of internal molecular degrees of freedom on the thermal conductivity of some glasses and disordered crystals

“…In this respect it is worth pointing out that the increase of the number of conformers within the asymmetric unit in a crystal makes it more difficult to find the thermodynamic path for energy minimization of the system as the temperature is lowered toward the ordered crystal ground state. 70,71 As far as the ordered phase II of C 6 CN is concerned, the contribution of the umklapp process is much larger than those for the orientationally ordered phases of C 6 OH. Because the umklapp process is the anharmonic phonon-phonon scattering process dominant for thermal resistivity providing the T −1 "pure" contribution, it can be concluded that this process is responsible for the low values of the thermal conductivity of C 6 CN beyond the phonon maximum if compared to values of the orientationally ordered phases of C 6 OH.…”

High pressure and low-temperature polymorphism in cyclopentanol

“…The molecules retain the same position in the hexagonal lattice, with different restricted rotations. [3] Phases III and IV have been confirmed as the monoclinic structure with space group C2/c and Cc, respectively, with a slight difference in the orientation of the molecule, resulting in the similar Raman spectrum. [3] Above 1.5 GPa, cyclopentanol crystallizes in the monoclinic P2 1 /c space group.…”

“…[3] Phases III and IV have been confirmed as the monoclinic structure with space group C2/c and Cc, respectively, with a slight difference in the orientation of the molecule, resulting in the similar Raman spectrum. [3] Above 1.5 GPa, cyclopentanol crystallizes in the monoclinic P2 1 /c space group. [11] However, it is observed that the Raman spectra of the crystalline state (phase III and IV) at lower temperature are different from that of the high pressure phase V. The peak splitting can be observed in the range of 800-950 cm −1 under high pressure, while it does not appear at the lower temperature.…”

“…Cyclopentanol (C 5 H 10 O) is one of the relatively simple examples, with a melting point of 255 K. Its polymorphism has been studied at low temperature using a variety of techniques such as calorimetry, spectroscopy, nuclear magnetic resonance spectroscopy and X-ray diffraction. [3,4] Two plastic crystal phases and more solid-to-solid phase transitions were reported below melting point. [5] It is well known that, besides temperature, pressure is another important thermodynamic parameter that greatly influences the structure and properties.…”

Raman study of plastic crystal phase of cyclooctanol under high pressure with different compression rate

“…In addition, the existence of the OeH group gives rise to a hydrogenbonding interaction, which certainly contributes to the stabilization of a crystal structure [14]. As shown in Fig.…”