Pressure effect on the solid–liquid equilibrium forms of odd normal alkanes

• Published in: Journal of crystal growth Vol. 310; no. 22; pp. 4681 - 4684
• Main Authors: Shigematsu, Koji, Saito, Yutaka, Saito, Kana, Takahashi, Yoshinori
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2008; Elsevier
• Subjects: A1. Crystal morphology; A1. Interfaces; A1. Phase equilibria; A2. Pressure-induced growth; B1. Organic compounds; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; High-pressure and shock-wave effects in solids and liquids; Materials science; Mechanical and acoustical properties of condensed matter; Methods of crystal growth; physics of crystal growth; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; 68.35.Wm; A1. Phase equilibria; 64.70.Dv; A2. Pressure-induced growth; A1. Interfaces; B1. Organic compounds; A1. Crystal morphology; Molecular arrangement; Crystal growth; High-pressure effects; Pressure effects; Diamonds; Alkanes; Thin films; Unit cell; Al. Interfaces; Crystal morphology; Orthorhombic crystals; Organic compounds; Temperature dependence; Bl. Organic compounds; Carbon; High pressure; Interfaces; Hexagonal lattices; Monocrystals; Anisotropy; Low pressure; Growth mechanism; Orthorhombic lattices; Al. Phase equilibria
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.08.043

This paper describes the changes in equilibrium forms of small odd-numbered normal alkane crystals (carbon number: 9, 11 and 13) as functions of temperature, pressure and the carbon number. The crystals were grown by increasing pressure of the liquids using a diamond anvil cell (DAC). After single crystals were prepared in the DAC under high pressure, the crystals were maintained for a long period under constant pressure and temperature. During the changes in the shape of the single crystal, both orthorhombic (high-pressure phase) and hexagonal (low-pressure phase) shapes appeared. These crystal shape variations, depending on pressure and temperature, were consistent for the anisotropies of the orthorhombic and hexagonal unit cells predicted from the molecular arrangements in the unit cells. Hexagonal thin films of n-tridecane could thus grow from the edges of the c-planes of orthorhombic thick plate of parallelogram.