This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee-Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report.

This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee-Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report.

This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee-Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report.

This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee-Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report.

This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee-Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report. A summary of the measurements reported here is given in Table 1, together with a list of experimental results that were reported previously and used in the generation of the derived properties.

This document is part of a series of reports describing experimental property measurements completed at the National Institute for Petroleum and Energy Research (NIPER) in Bartlesville, Oklahoma, in the 1980s and 1990s. Members of the Bartlesville Thermodynamics Group included William D. "Bill" Good, William V. "Bill" Steele, Bruce E. Gammon, Norris K. Smith, Stephen E. Knipmeyer, An "Andy" Nguyen, Timothy D. Klots, I. A. "Alex" Hossenlopp, Aaron P. Rau, William B. Collier, John F. Messerly, Ann G. Osborn, Susan Lee Bechtold, Donald G. Archer, Ian R. Tasker, Allan B. Cowell, Michael M. Strube, and the author of this report.

This data set contains enthalpies of formation, entropies, heat capacities, and thermal enthalpies for about 400 compounds available in the NIST TRC SOURCE database. The enthalpies of formation are computed using the ab initio-based protocol reported in the references below. The other properties are calculated by statistical thermodynamics using the "rigid rotor - harmonic oscillator" approximation. The conformational contributions are found by the Gibbs energy averaging of the properties of the conformers.

Recommended values are provided for chemical thermodynamic properties of inorganic substances and for organic substances usually containing only one or two carbon atoms. Where available, values are given for the enthalpy of formation, Gibbs energy of formation, entropy, and heat capacity at 298.15 K (25 degrees C), the enthalpy difference between 298.15 and 0 K and the enthalpy of formation at 0 K. All values are given in SI units and are for a standard state pressure of 100 000 pascal. This volume is a new collective edition of "Selected Values of Chemical Thermodynamic Properties," which was issued serially as National Bureau of Standards Technical Notes 270-1 (1965) to 270-8 (1981). Values are given for properties of gaseous, liquid and crystalline substances, for solutions in water, and for mixed aqueous and organic solutions. Values are not given for alloys or other solid solutions, fused salts or for substances of undefined composition. Compounds of the transuranium elements are not included.

Supplemental material to the 2025 article "Demonstration of dispersion gas barometry" by Y. Yang, J.A. Stone, and P.F. Egan.The archive file contains two-color data for the gases helium, neon, argon, and nitrogen. Two-color data means measured quadruplets of pressure and temperature together with refractivity at two wavelengths 1542.3912 nm (194.368624 THz) and 632.9919 nm (473.611873 THz).Two analysis scripts are included:1. plotHelium.py: performs the helium analysis to deduce the cavity distortion coefficient kappa and the conversion factor epsilon_p needed to realize the optical pressure scale. The script reproduces Fig. 2 from the article.2. plotGases.py: analyzes the gases neon, argon, and nitrogen and deduces the two parameters describing dispersion polarizability A_epsilon and A_2. The script reproduces Fig 3 from the article.Additionally, the script "pgtProp.py" is a library function, which offers best knowledge (as of January 2025) of gas properties to be used in Polarizing Gas Thermometry. The library functions synthesize the optical and thermophysical properties of helium, neon, argon, and nitrogen. The synthesis combines literature sources plus the measurement results from the main text.