http://webbook.nist.gov/chemistry/fluid/
Accurate thermophysical properties are available for several fluids. These data include the following:
Density
Cp
Enthalpy
Internal energy
Viscosity
Joule-Thomson coefficient
Specific volume
Cv
Entropy
Speed of Sound
Thermal conductivity
Surface tension (saturation curve only)
for
Isothermal properties
Saturation properties -- temperature increments
Isobaric properties
Saturation properties -- pressure increments
Isochoric properties
National Institute of Standards and Technology