Hydrogen iodide

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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
Δfgas6.334 ± 0.024kcal/molReviewCox, Wagman, et al., 1984CODATA Review value
Δfgas6.300kcal/molReviewChase, 1998Data last reviewed in September, 1961
Quantity Value Units Method Reference Comment
gas,1 bar49.376cal/mol*KReviewChase, 1998Data last reviewed in September, 1961

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 (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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View table.

Temperature (K) 298. to 1400.1400. to 6000.
A 6.2250008.471219
B 1.1208600.338123
C 1.173941-0.043520
D -0.6344160.002813
E 0.029020-0.969063
F 4.4825511.892711
G 56.6925957.38760
H 6.2999606.299960
ReferenceChase, 1998Chase, 1998
Comment Data last reviewed in September, 1961 Data last reviewed in September, 1961

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 as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Quantity Value Units Method Reference Comment
Tfus222.15KN/ABeckmann and Waentig, 1910Uncertainty assigned by TRC = 1.5 K; TRC

Enthalpy of vaporization

ΔvapH (kcal/mol) Temperature (K) Method Reference Comment
4.73238.CGiauque and Wiebe, 1929AC

Antoine Equation Parameters

log10(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Temperature (K) A B C Reference Comment
149.8 to 238.14.26283939.994-18.012Stull, 1947Coefficents calculated by NIST from author's data.

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:


Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, Ion clustering 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:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to HI+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)10.386 ± 0.001eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)150.0kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity143.7kcal/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
10.38PEKimura, Katsumata, et al., 1981LLK
10.386 ± 0.001SEland and Berkowitz, 1977LLK
10.38 ± 0.01PELempka, Passmore, et al., 1968RDSH
10.42 ± 0.01PEFrost, McDowell, et al., 1967RDSH
10.38 ± 0.02PIWatanabe, 1957RDSH
10.3 ± 0.1EIFriedman, 1955RDSH
~10.39SPrice, 1938RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
I+13.49 ± 0.13?PIEland and Berkowitz, 1977LLK

De-protonation reactions

Iodide + Hydrogen cation = Hydrogen iodide

By formula: I- + H+ = HI

Quantity Value Units Method Reference Comment
Δr314.350 ± 0.020kcal/molD-EAPelaez, Blondel, et al., 2009gas phase; Given: 3.0590463(38) eV; B
Δr313.60kcal/molN/ACheck, Faust, et al., 2001gas phase; Fe(CO)2-(q); ; ΔS(EA)=5.0; B
Quantity Value Units Method Reference Comment
Δr309.280 ± 0.060kcal/molH-TSPelaez, Blondel, et al., 2009gas phase; Given: 3.0590463(38) eV; B
Δr308.50kcal/molN/ACheck, Faust, et al., 2001gas phase; Fe(CO)2-(q); ; ΔS(EA)=5.0; B

Ion clustering 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 as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

Iodide + Hydrogen iodide = (Iodide • Hydrogen iodide)

By formula: I- + HI = (I- • HI)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr17.0 ± 2.0kcal/molTDEqCaldwell and Kebarle, 1985gas phase; B,M
Quantity Value Units Method Reference Comment
Δr24.4cal/mol*KPHPMSCaldwell and Kebarle, 1985gas phase; switching reaction(I-)SO2; M
Quantity Value Units Method Reference Comment
Δr9.7 ± 2.6kcal/molTDEqCaldwell and Kebarle, 1985gas phase; B

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
9.7300.PHPMSCaldwell and Kebarle, 1985gas phase; switching reaction(I-)SO2; M

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering 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]

Beckmann and Waentig, 1910
Beckmann, E.; Waentig, P., Cryoscopic Measurements at Low Temperatures, Z. Anorg. Chem., 1910, 67, 17. [all data]

Giauque and Wiebe, 1929
Giauque, W.F.; Wiebe, R., THE HEAT CAPACITY OF HYDROGEN IODIDE FROM 15°K. TO ITS BOILING POINT AND ITS HEAT OF VAPORIZATION. THE ENTROPY FROM SPECTROSCOPIC DATA, J. Am. Chem. Soc., 1929, 51, 5, 1441-1449, https://doi.org/10.1021/ja01380a019 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [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]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Eland and Berkowitz, 1977
Eland, J.H.D.; Berkowitz, J., Photoionization mass spectrometry of HI and DI at high resolution, J. Chem. Phys., 1977, 67, 5034. [all data]

Lempka, Passmore, et al., 1968
Lempka, H.J.; Passmore, T.R.; Price, W.C., The photoelectron spectra and ionized states of the halogen acids, Proc. Roy. Soc. (London), 1968, A304, 53. [all data]

Frost, McDowell, et al., 1967
Frost, D.C.; McDowell, C.A.; Vroom, D.A., Photoelectron spectra of the halogens and the hydrogen halides, J. Chem. Phys., 1967, 46, 4255. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Friedman, 1955
Friedman, L., Mass spectrum of lithium iodide, J. Chem. Phys., 1955, 23, 477. [all data]

Price, 1938
Price, W.C., The absorption spectra of the halogen acids in the vacuum ultra-violet, Proc. Roy. Soc. (London), 1938, A167, 216. [all data]

Pelaez, Blondel, et al., 2009
Pelaez, R.J.; Blondel, C.; Delsart, C.; Drag, C., Pulsed photodetachment microscopy and the electron affinity of iodine, J. Phys. B: Atom. Mol. Opt. Phys., 2009, 42, 12, 125001, https://doi.org/10.1088/0953-4075/42/12/125001 . [all data]

Check, Faust, et al., 2001
Check, C.E.; Faust, T.O.; Bailey, J.M.; Wright, B.J.; Gilbert, T.M.; Sunderlin, L.S., Addition of Polarization and Diffuse Functions to the LANL2DZ Basis Set for P-Block Elements, J. Phys. Chem. A,, 2001, 105, 34, 8111, https://doi.org/10.1021/jp011945l . [all data]

Caldwell and Kebarle, 1985
Caldwell, G.; Kebarle, P., The hydrogen bond energies of the bihalide ions XHX- and YHX-, Can. J. Chem., 1985, 63, 1399. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, References