Journal ArticleDOI
Anisotropy of Intermolecular Interactions from the Study of the Thermal-Expansion Tensor
TLDR
In this article, the anisotropy of the intermolecular interactions in the low-temperature ordered phases of three chemically and structurally related compounds [neopentyl glycol, (CH3)2C(CH2OH)2, pivalic acid, CH3)3C(COOH), and neopentylon alcohol, all of which display an orientationally disordered high temperature phase, has been shown by means of the isobaric thermalexpansion tensor.Abstract:
The anisotropy of the intermolecular interactions in the low-temperature ordered phases of three chemically and structurally related compounds [neopentylglycol, (CH3)2C(CH2OH)2, pivalic acid, (CH3)3C(COOH), and neopentylalcohol, (CH3)3C(CH2OH)], all of which display an orientationally disordered high-temperature phase, has been shown by means of the isobaric thermal-expansion tensor. The variation of the directions of the principal components of the thermal-expansion tensor as a function of temperature, as well as the variation of its principal coefficients, is evidence of the large differences in the intermolecular interactions for each compound; or, more precisely, between the strong intermolecular hydrogen bonds and the weak van der Waals interactions. In addition, the differences in the hydrogen-bonding schemes expected a priori from the molecular structures of the studied compounds have been enhanced. Finally, the volume expansivity as well as the packing coefficient have been analysed in the orientationally disordered high-temperature phase of each of the three compounds.Part of this work was presented at the EPDIC 1997 meeting (5th European Powder Diffraction Conference).read more
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Reversible and irreversible colossal barocaloric effects in plastic crystals
Araceli Aznar,Pol Lloveras,Maria Barrio,Philippe Négrier,Antoni Planes,Lluís Mañosa,Neil D. Mathur,Xavier Moya,Josep-Lluís Tamarit +8 more
TL;DR: In this article, the reversible barocaloric response of four plastic crystals derived from neopentane [C(CH3)4] was determined, and the minimum pressure needed to achieve reversible effects, prev, for each compound was determined using the quasi-direct method.
Journal ArticleDOI
Thermal Expansion in Alkane Diacids—Another Property Showing Alternation in an Odd–Even Series
TL;DR: The thermal expansion of HOOC(CH2)n−2COOH (n = 2−10) has been studied in this paper, showing a trend of higher thermal expansion anisotropy for odd members in the series compared to the even members.
Journal ArticleDOI
Achieving dynamic behaviour and thermal expansion in the organic solid state via co-crystallization
Kristin M. Hutchins,Ryan H. Groeneman,Eric W. Reinheimer,Dale C. Swenson,Leonard R. MacGillivray +4 more
TL;DR: Molecular motion of an azo functional group is ‘unlocked’ via co-crystallizations through co-Crystallizations.
Journal ArticleDOI
Interaction Dependence and Similarity in Thermal Expansion of a Dimorphic 1D Hydrogen-Bonded Organic Complex
Suman Bhattacharya,Binoy K. Saha +1 more
TL;DR: The thermal expansion trends for the two one-dimensional hydrogen-bonded 1:2 cocrystal polymorphs of 1,2,3,4-cyclobutanetetetracarboxylic acid and trans-1,2-bis(4-pyridyl)ethylene have been studied in this article.
Journal ArticleDOI
Polymorphism of CBrCl3
Benjamin Parat,Luis Carlos Pardo,Maria Barrio,Josep Ll. Tamarit,Philippe Négrier,Josep Salud,David López,Denise Mondieig +7 more
TL;DR: In this article, the existence of a glass transition from the monoclinic low-temperature stable ordered phase (III) to its nonergodic state (associated with the freezing of exchange positions between Cl and Br atoms) is analyzed in terms of the asymmetry of the intermolecular interactions, and a new fingerprint for the glass transition is proposed on the basis of the aspherism index.
References
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Journal ArticleDOI
Solid state phase transitions in pentaerythritol and related polyhydric alcohols
TL;DR: The thermodynamic properties and mechanisms of solid state phase transformations in some hydrocarbon molecular crystals reversibly absorb large amounts of heat as discussed by the authors have been studied for polyhydric alcohols related to pentaerythritol.
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Potential of the INEL X-ray position-sensitive detector : a general study of the Debye-Scherrer setting
TL;DR: The INEL diffractometer, equipped with a CPS120 curved detector and set up in a Debye-Scherrer geometry, is a unique tool for carrying out powder diffraction studies on air-sensitive and/or small volume samples as mentioned in this paper.
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Evolution des tenseurs de dilatation thermique en fonction de la temperature. I. Loi generale d'evolution de la symetrie du tenseur
TL;DR: In this article, the variation of the symmetry of the thermal expansion tensor as a function of temperature was studied and a measure of this symmetry, called aspherism index, was defined.
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Dielectric studies under pressure on plastic and liquid crystals
TL;DR: In this article, the authors give an account of dielectric studies under high pressure on plastic and liquid crystalline phases, emphasizing the usefulness of employing hydrostatic pressure as an important parameter for varying the average inter-molecular distance.