Argon
- Formula: Ar
- Molecular weight: 39.948
- IUPAC Standard InChI: InChI=1S/Ar
- IUPAC Standard InChIKey: XKRFYHLGVUSROY-UHFFFAOYSA-N
- CAS Registry Number: 7440-37-1
- Chemical structure:
This structure is also available as a 2d Mol file - Other names: Ar; UN 1006; UN 1951; argon atom
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- NIST Atomic Spectra Database - Lines Holdings (on physics web site)
- NIST Atomic Spectra Database - Levels Holdings (on physics web site)
- NIST Atomic Spectra Database - Ground states and ionization energies (on physics web site)
- Gas Phase Kinetics Database
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- X-ray Photoelectron Spectroscopy Database, version 5.0
- Options:
Data at NIST subscription sites:
- NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
- NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)
NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.
Gas phase thermochemistry data
Go To: Top, Phase change data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| S°gas,1 bar | 154.846 ± 0.003 | J/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 154.84 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1982 |
Gas Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
View plot Requires a JavaScript / HTML 5 canvas capable browser.
| Temperature (K) | 298. to 6000. |
|---|---|
| A | 20.78600 |
| B | 2.825911×10-7 |
| C | -1.464191×10-7 |
| D | 1.092131×10-8 |
| E | -3.661371×10-8 |
| F | -6.197350 |
| G | 179.9990 |
| H | 0.000000 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1982 |
Phase change data
Go To: Top, Gas phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Tboil | 87.5 | K | N/A | Streng, 1971 | Uncertainty assigned by TRC = 0.3 K; TRC |
| Tboil | 87.28 | K | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.02 K; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Tfus | 83.8 | K | N/A | Van't Zelfde, Omar, et al., 1968 | Uncertainty assigned by TRC = 0.3 K; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Ttriple | 87.78 | K | N/A | Angus, Armstrong, et al., 1972 | Uncertainty assigned by TRC = 0.05 K; TRC |
| Ttriple | 83.8 | K | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.05 K; TRC |
| Ttriple | 83.8 | K | N/A | Ziegler, Mullins, et al., 1962 | Uncertainty assigned by TRC = 0.05 K; TRC |
| Ttriple | 83.78 | K | N/A | Clark, Din, et al., 1951 | Uncertainty assigned by TRC = 0.04 K; TRC |
| Ttriple | 83.78 | K | N/A | Clusius and Weigand, 1940 | Uncertainty assigned by TRC = 0.2 K; See property X for dP/dT at triple point; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Ptriple | 0.689 | bar | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.0001 bar; TRC |
| Ptriple | 0.689 | bar | N/A | Ziegler, Mullins, et al., 1962 | Uncertainty assigned by TRC = 0.0001 bar; TRC |
| Ptriple | 0.6875 | bar | N/A | Clark, Din, et al., 1951 | Uncertainty assigned by TRC = 0.0007 bar; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Tc | 150.86 | K | N/A | Angus, Armstrong, et al., 1972 | Uncertainty assigned by TRC = 0.1 K; TRC |
| Tc | 150.86 | K | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.1 K; TRC |
| Tc | 150.65 | K | N/A | McCain and Ziegler, 1967 | Uncertainty assigned by TRC = 0.03 K; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Pc | 4.8979 | bar | N/A | Angus, Armstrong, et al., 1972 | Uncertainty assigned by TRC = 0.002 bar; TRC |
| Pc | 48.9805 | bar | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.1013 bar; TRC |
| Pc | 48.5549 | bar | N/A | McCain and Ziegler, 1967 | Uncertainty assigned by TRC = 0.0709 bar; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| ρc | 13.41 | mol/l | N/A | Angus, Armstrong, et al., 1972 | Uncertainty assigned by TRC = 0.005 mol/l; TRC |
| ρc | 8.4029 | mol/l | N/A | Gosman, McCarty, et al., 1969 | Uncertainty assigned by TRC = 0.008 mol/l; TRC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)
View plot Requires a JavaScript / HTML 5 canvas capable browser.
| Temperature (K) | A | B | C | Reference | Comment |
|---|---|---|---|---|---|
| 114.40 to 150.31 | 4.46903 | 481.012 | 22.156 | McCain and Ziegler, 1967 | Coefficents calculated by NIST from author's data. |
| 83.78 to 150.72 | 3.29555 | 215.24 | -22.233 | Drii and Rabinovich, 1966 | Coefficents calculated by NIST from author's data. |
| 129.33 to 147.40 | 4.97171 | 658.982 | 49.819 | van Itterbeek, Verbeke, et al., 1963 | Coefficents calculated by NIST from author's data. |
| 90.94 to 101.48 | 3.73479 | 302.683 | -6.083 | Clark, Din, et al., 1951, 2 | Coefficents calculated by NIST from author's data. |
References
Go To: Top, Gas phase thermochemistry data, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A.,
CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Streng, 1971
Streng, A.G.,
Miscibility and Compatibility of Some Liquid and Solidified Gases at Low Temperature,
J. Chem. Eng. Data, 1971, 16, 357. [all data]
Gosman, McCarty, et al., 1969
Gosman, A.L.; McCarty, R.D.; Hust, J.G.,
Thermodynamic Properties of Argon from the Triple Point to 300 K at Pressures to 1000 Atmospheres, Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. NSRDS-NBS 27, 1969. [all data]
Van't Zelfde, Omar, et al., 1968
Van't Zelfde, P.; Omar, M.H.; LePair-Schroten, H.G.M.; Dokoupil, Z.,
Solid-liquid equilibrium diagram for the argon + methane system.,
Physica (Amsterdam), 1968, 38, 241-51. [all data]
Angus, Armstrong, et al., 1972
Angus, S.; Armstrong, B.; Gosman, A.L.; McCarty, R.D.; Hust, J.G.; Vasserman, A.A.; Rabinovich, V.A.,
International Thermodynamic Tables of the Fluid State - 1 Argon, Butterworths, London, 1972. [all data]
Ziegler, Mullins, et al., 1962
Ziegler, W.T.; Mullins, J.C.; Kirk, B.S.,
Calculation of the Vapor Pressure and Heats of Vaporization and Sublimation of Liquids and Solids, Especially Below One Atmosphere Pressure. II. Argon, Ga. Inst. Technol., Eng. Exp. Stn., Proj. A-460, Tech. Rep. No. 2, 1962. [all data]
Clark, Din, et al., 1951
Clark, A.M.; Din, F.; Robb, J.; Michels, A.; Wassenaar, T.; Zwietering, Th.N.,
The Vapor Pressure of Argon,
Physica (Amsterdam), 1951, 17, 876. [all data]
Clusius and Weigand, 1940
Clusius, K.; Weigand, K.,
Melting Curves of the Gases A, Kr, Xe, CH4, CH3D, CD4, C2H4, C2H6, COS, and PH3 to 200 Atmospheres Pressure. The Chane of Volume on Melting,
Z. Phys. Chem., Abt. B, 1940, 46, 1-37. [all data]
McCain and Ziegler, 1967
McCain, W.D., Jr.; Ziegler, W.T.,
The Critical Temperature, Critical Pressure, and Vapor Pressure of Argon,
J. Chem. Eng. Data, 1967, 12, 2, 199-202, https://doi.org/10.1021/je60033a012
. [all data]
Drii and Rabinovich, 1966
Drii, L.I.; Rabinovich, V.A.,
Dependence of Vapor Pressure of Argon,
Zh. Fiz. Khim., 1966, 40, 709-711. [all data]
van Itterbeek, Verbeke, et al., 1963
van Itterbeek, A.; Verbeke, O.; Staes, K.,
Measurements on the Equation of State of Liquid Argon and Methane Up to 300 kg cm-2 at Low Temperatures,
Physica (Amsterdam), 1963, 29, 6, 742-754, https://doi.org/10.1016/S0031-8914(63)80231-1
. [all data]
Clark, Din, et al., 1951, 2
Clark, A.M.; Din, F.; Robb, J.; Michels, A.; Wassenaar, T.; Zwietering, Th.,
The Vapour Pressure of Argon,
Physica (Amsterdam), 1951, 17, 10, 876-884, https://doi.org/10.1016/0031-8914(51)90041-9
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Phase change data, References
- Symbols used in this document:
Pc Critical pressure Ptriple Triple point pressure S°gas,1 bar Entropy of gas at standard conditions (1 bar) Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.