Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Thermodynamic Properties of Sulfur Hexafluoride

Published

Author(s)

John J. Hurly, Dana R. Defibaugh, Michael R. Moldover

Abstract

We present new vapor phase speed-of-sound data u(P,T), new Burnett density-pressure-temperature data ρ(P,T), and a few vapor pressure measurements for sulfur hexafluoride (SF6). The speed-of-sound data spanned the temperature range 230 K {less than or equal to} T {less than or equal to} 460 K and reached maximum pressures that were the lesser of 1.5 MPa or 80% of the vapor pressure of SF6. The Burnett ρ(P,T) data were obtained on isochores spanning the density range 137 mol . m-3 {less than or equal to} ρ {less than or equal to} 4380 mol . m^-3^ and the temperature range 283 K {less than or equal to} T {less than or equal to} 393 K. (The corresponding pressure range is 0.3 MPa {less than or equal to} P {less than or equal to} 9.0 MPa.) The u(P,T) data below 1.5 MPa were correlated using a model hard-core, Lennard-Jones intermolecular potential for the second and third virial coefficients and a polynomial for the perfect gas heat capacity. The resulting equation of state has very high accuracy at low densities; it is useful for calibrating mass flow controllers and may be extrapolated to 1000 K. The new u(P,T) data and the new ρ(P,T) data were simultaneously correlated with a virial equation of state containing four terms with the temperature dependencies of model square-well potentials. This correlation extends nearly to the critical density and may help resolve contradictions among data sets from the literature.
Citation
International Journal of Thermophysics
Volume
21
Issue
No. 3

Keywords

Burnett, equation-of-state, heat capacity, intermolecular potential, SF<sub>6</sub>, speed-of-sound, sulfur hexafluoride, thermodynamic properties, vapor pressure

Citation

Hurly, J. , Defibaugh, D. and Moldover, M. (2000), Thermodynamic Properties of Sulfur Hexafluoride, International Journal of Thermophysics (Accessed March 29, 2024)
Created May 1, 2000, Updated June 2, 2021