helium

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Gas phase thermochemistry data

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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
gas,1 bar126.153 ± 0.002J/mol*KReviewCox, Wagman, et al., 1984CODATA Review value
gas,1 bar126.15J/mol*KReviewChase, 1998Data 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.

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Temperature (K) 298. to 6000.
A 20.78603
B 4.850638×10-10
C -1.582916×10-10
D 1.525102×10-11
E 3.196347×10-11
F -6.197341
G 151.3064
H 0.000000
ReferenceChase, 1998
Comment Data last reviewed in March, 1982

Phase change data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director

Quantity Value Units Method Reference Comment
Tc5.2KN/AAngus, de Reuck, et al., 1977Uncertainty assigned by TRC = 0.0005 K; in terms of a temp. scale related to the 1958 He-4 scale, T-58 by 1.001 T-58 + 0.001 K
Quantity Value Units Method Reference Comment
Pc2.274barN/AAngus, de Reuck, et al., 1977Uncertainty assigned by TRC = 0.002 bar
Quantity Value Units Method Reference Comment
ρc17.40mol/lN/AAngus, de Reuck, et al., 1977Uncertainty assigned by TRC = 0.01 mol/l

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Henry's Law data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Rolf Sander

Henry's Law constant (water solution)

kH(T) = H exp(d(ln(kH))/d(1/T) ((1/T) - 1/(298.15 K)))
H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(kH))/d(1/T) = Temperature dependence constant (K)

H (mol/(kg*bar)) d(ln(kH))/d(1/T) (K) Method Reference Comment
0.0003892.LN/A 
0.00037360.MN/AInterpolation of the original data at T < 300. K. According to missing citation the solubility increases at higher temperatures.

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, Henry's Law data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity Value Units Method Reference Comment
IE (evaluated)24.58741eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)177.8kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity148.5kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
24.58741EVALLide, 1992LL
24.56EIWetzel, Baiocchi, et al., 1987LBLHLM
24.588SKelly, 1987LBLHLM
24.58741SMoore, 1970RDSH
24.59 ± 0.03EIKaneko, 1960RDSH
24.6 ± 0.1PIWeissler, Samson, et al., 1959RDSH

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Henry's Law data, Gas phase ion energetics 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]

Angus, de Reuck, et al., 1977
Angus, S.; de Reuck, K.M.; McCarty, R.D., International Thermodynamic Tables of the Fluid State - 4 Helium, Pergamon, New York, 1977. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Lide, 1992
Lide, D.R. (Editor), Ionization potentials of atoms and atomic ions in Handbook of Chem. and Phys., 1992, 10-211. [all data]

Wetzel, Baiocchi, et al., 1987
Wetzel, R.C.; Baiocchi, F.A.; Hayes, T.R.; Freund, R.S., Absolute cross sections for electron-impact ionization of the rare-gas atoms by the fast-neutral-beam method, Phys. Rev. A, 1987, 35, 559. [all data]

Kelly, 1987
Kelly, R.L., Atomic and ionic spectrum lines of hydrogen through kryton, J. Phys. Chem. Ref. Data, 1987, 16. [all data]

Moore, 1970
Moore, C.E., Ionization potentials and ionization limits derived from the analyses of optical spectra, Natl. Stand. Ref. Data Ser., (U.S. Natl. Bur. Stand.), 1970, 34, 1. [all data]

Kaneko, 1960
Kaneko, Y., Ionization efficiency curves for A+, Kr+, N2+, and CO+ by electron impact, J. Phys. Soc. Japan, 1960, 16, 1587. [all data]

Weissler, Samson, et al., 1959
Weissler, G.L.; Samson, J.A.R.; Ogawa, M.; Cook, G.R., Photoionization analysis by mass spectroscopy, J. Opt. Soc. Am., 1959, 49, 338. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Henry's Law data, Gas phase ion energetics data, References