**NITROGEN**

NITROGEN provides thermodynamic properties using the fundamental equation of state reported by:

Span, R., Lemmon, E.W,, Jacobsen, R.T., Wagner, W., and Yokozeki, A.,

"A Reference Equation of State for the Thermodynamic Properties of Nitrogen for Temperatures from 63.151 to 1000 K and Pressures to 2200 MPa"

J. Phys. Chem. Ref. Data, Vol. 29, No. 6, 2000

The reference state for specific enthalpy and entropy are 0 at 0 K and 101.325 kPa for the ideal gas state. The reference state can be changed using the $Reference directive.

Note that NITROGEN provides thermodynamic properties assuming real fluid behavior. Use N2 for ideal gas properties of nitrogen consistent with reference states used in combustion calculations.

__The transport properties are implemented with the equations provided in:__

E.W. Lemmon and R.T. Jacobsen

*"Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air"*,

International Journal of Thermophysics, Vol. 25, No. 1, January 2004, pp. 21-69

__Surface tension data are provided using the information in:__

Mulero, A., Cachadina, I, and Parra, M.

"Recommended Correlations for the Surface Tension of Common Fluids"

J.Phys. Chem Ref. Data, Vol. 41, No.4, 2012

__The melting pressure curve (valid for temperatures between 63.15 K and 191 K) is determined from:__

Span, R., Lemmon, E.W,, Jacobsen, R.T., Wagner, W., and Yokozeki, A., (referenced above)

__The sublimation pressure curve (valid for temperatures between 20 K and 63.15) is determined from:__

N.Fray, B.Schmitt,

"Sublimation of ices of astrophysical interest:A bibliographic review"

Planetary and Space Science,57, (2009) pp. 2053-208

(Note that solid nitrogen exists in two crystalline structures with a phase change occurring at 35.7 K.)