Heats of sublimation from a polycrystalline mixture of C sub 60 and C sub 70

Journal Article · Thu Apr 18 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100161a003· OSTI ID:5759255

Pan, C; Sampson, M P; Chai, Y; Hauge, R H; Margrave, J L ^[1]

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1. Rice Univ., Houston, TX (United States)

Knudsen effusion mass spectrometric measurements of vapors in equilibrium with a polycrystalline mixture of C{sub 60} and C{sub 70} were carried out over the temperature range 640-800 K. From the second-law method, average values obtained for the heats of sublimation of C{sub 60} and C{sub 70} from a polycrystalline C{sub 60} matrix were found to be respectively 40.1 {plus minus} 1.3 and 43.0 {plus minus} 2.2 kcal mol{sup {minus}1}, at the average temperatures 707 and 739 K. It was also noted that it was necessary to heat treat the samples at temperatures of at least 170 C for greater than 12 h to achieve stable vaporization. This was consistent with the sample becoming more crystalline.

• OSTI ID: 5759255
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:8; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
CARBON
COHERENT SCATTERING
CRYSTALS
DATA
DIFFRACTION
ELEMENTS
ENTHALPY
EXPERIMENTAL DATA
FLUID FLOW
FULLERENES
GAS FLOW
INFORMATION
KNUDSEN FLOW
MASS SPECTROSCOPY
NONMETALS
NUMERICAL DATA
PARTIAL PRESSURE
PHYSICAL PROPERTIES
POLYCRYSTALS
SAMPLE PREPARATION
SCATTERING
SPECTROSCOPY
SUBLIMATION HEAT
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMODYNAMIC PROPERTIES
TRANSITION HEAT
X-RAY DIFFRACTION