Equation forms developed for use in correlating thermodynamic and transport properties with temperature have been developed and tested over almost 2 decades using a large pool of critically evaluated data over a wide temperature range. Usually only one equation form has been used for any single property in a given phase; however, alternate forms are sometimes recommended. Properties treated are solid and liquid vapor pressure, heat of vaporization, liquid and solid density, solid, liquid, and ideal gas heat capacity, second virial, coefficient, liquid and vapor viscosity, liquid and vapor thermal conductivity, and surface tension. Equation forms vary from empirical polynomials to theoretically based forms, including polynomials, exponentials, inverse power, and trigonometric functions in temperature.