Hydrogen atom

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Gas phase thermochemistry data

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics 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
Δfgas217.998 ± 0.006kJ/molReviewCox, Wagman, et al., 1984CODATA Review value
Δfgas218.00kJ/molReviewChase, 1998Data last reviewed in March, 1982
Quantity Value Units Method Reference Comment
gas,1 bar114.717 ± 0.002J/mol*KReviewCox, Wagman, et al., 1984CODATA Review value
gas,1 bar114.72J/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 211.8020
G 139.8711
H 217.9994
ReferenceChase, 1998
Comment Data last reviewed in March, 1982

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics 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:
MS - José A. Martinho Simões
B - John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

Hydromanganese pentacarbonyl (solution) = Hydrogen atom (solution) + C5MnO5 (solution)

By formula: C5HMnO5 (solution) = H (solution) + C5MnO5 (solution)

Quantity Value Units Method Reference Comment
Δr284.5 ± 4.2kJ/molEChemParker, Handoo, et al., 1991solvent: Acetonitrile; Please also see Tilset and Parker, 1989. The reaction enthalpy was obtained from the pKa of the hydride complex (MH), 14.1, and from the oxidation potential of the anion (M-), Mn(CO)5(-), by using the equation: ΔHrxn [kJ/mol] = 5.71pKa(MH) + 96.485(Eo)ox(M-) + C. C is a constant that was calculated as 248.9 kJ/mol Parker, Handoo, et al., 1991, by adjusting the previous equation to the calorimetrically derived values for the reactions Cr(Cp)(CO)3(H)(solution) = Cr(Cp)(CO)3(solution) + H(solution), 257.3 ± 4.2 kJ/mol, and Cr(Cp)(CO)2(PPh3)(H)(solution) = Cr(Cp)(CO)2(PPh3)(solution) + H(solution), 250.2 ± 4.2 kJ/mol Kiss, Zhang, et al., 1990. C depends on the solvent and on the reference electrode. The value given implies that the electrode potentials are referenced to ferrocene/ferricinium electrode; MS
Δr269.7kJ/molKinSBillmers, Griffith, et al., 1986solvent: Benzene; Please also see Sweany, Butler S.C., et al., 1981. The reaction enthalpy was derived according to the following procedure: the activation energy for the reaction 9,10-Me2C14H8(solution) + 2Mn(CO)5(H)(solution) = 9,10-Me2C14H10(solution) + Mn2(CO)10(solution), 90.8 kJ/mol, was reported in Sweany, Butler S.C., et al., 1981. The rate-limiting step of this reaction is the abstraction of hydrogen from Mn(CO)5(H), producing Mn(CO)5 and 9,10-Me2C14H9 radicals. Therefore, the activation energy is approximately equal to the difference between the enthalpies of the reactions Mn(CO)5(H)(solution) = Mn(CO)5(solution) + H(solution) and 9,10-Me2C14H9(solution) = 9,10-Me2C14H8(solution). The latter was taken as 178.9 kJ/mol Billmers, Griffith, et al., 1986; MS

C7H6FeO2 (solution) = C7H5FeO2 (solution) + Hydrogen atom (solution)

By formula: C7H6FeO2 (solution) = C7H5FeO2 (solution) + H (solution)

Quantity Value Units Method Reference Comment
Δr238.9 ± 4.2kJ/molEChemParker, Handoo, et al., 1991solvent: Acetonitrile; Please also see Tilset and Parker, 1989. The reaction enthalpy was obtained from the pKa of the hydride complex (MH), 19.4, and from the oxidation potential of the anion (M-), Fe(Cp)(CO)2(-), by using the equation: ΔHrxn [kJ/mol] = 5.71pKa(MH) + 96.485(Eo)ox(M-) + C. C is a constant that was calculated as 248.9 kJ/mol Parker, Handoo, et al., 1991, by adjusting the previous equation to the calorimetrically derived values for the reactions Cr(Cp)(CO)3(H)(solution) = Cr(Cp)(CO)3(solution) + H(solution), 257.3 ± 4.2 kJ/mol, and Cr(Cp)(CO)2(PPh3)(H)(solution) = Cr(Cp)(CO)2(PPh3)(solution) + H(solution), 250.2 ± 4.2 kJ/mol Kiss, Zhang, et al., 1990. C depends on the solvent and on the reference electrode. The value given implies that the electrode potentials are referenced to ferrocene/ferricinium electrode; MS

C5HO5Re (solution) = Hydrogen atom (solution) + C5O5Re (solution)

By formula: C5HO5Re (solution) = H (solution) + C5O5Re (solution)

Quantity Value Units Method Reference Comment
Δr312.5 ± 4.2kJ/molEChemParker, Handoo, et al., 1991solvent: Acetonitrile; Please also see Tilset and Parker, 1989. The reaction enthalpy was obtained from the pKa of the hydride complex (MH), 21.1, and from the oxidation potential of the anion (M-), Re(CO)5(-), by using the equation: ΔHrxn [kJ/mol] = 5.71pKa(MH) + 96.485(Eo)ox(M-) + C. C is a constant that was calculated as 248.9 kJ/mol Parker, Handoo, et al., 1991, by adjusting the previous equation to the calorimetrically derived values for the reactions Cr(Cp)(CO)3(H)(solution) = Cr(Cp)(CO)3(solution) + H(solution), 257.3 ± 4.2 kJ/mol, and Cr(Cp)(CO)2(PPh3)(H)(solution) = Cr(Cp)(CO)2(PPh3)(solution) + H(solution), 250.2 ± 4.2 kJ/mol Kiss, Zhang, et al., 1990. C depends on the solvent and on the reference electrode. The value given implies that the electrode potentials are referenced to ferrocene/ferricinium electrode; MS

Cobalt, tetracarbonylhydro- (solution) = Hydrogen atom (solution) + Cobalt, tetracarbonyl (solution)

By formula: C4HCoO4 (solution) = H (solution) + C4CoO4 (solution)

Quantity Value Units Method Reference Comment
Δr277.8 ± 4.2kJ/molEChemParker, Handoo, et al., 1991solvent: Acetonitrile; Please also see Tilset and Parker, 1989. The reaction enthalpy was obtained from the pKa of the hydride complex (MH), 8.3, and from the oxidation potential of the anion (M-), Co(CO)4(-), by using the equation: ΔHrxn [kJ/mol] = 5.71pKa(MH) + 96.485(Eo)ox(M-) + C. C is a constant that was calculated as 248.9 kJ/mol Parker, Handoo, et al., 1991, by adjusting the previous equation to the calorimetrically derived values for the reactions Cr(Cp)(CO)3(H)(solution) = Cr(Cp)(CO)3(solution) + H(solution), 257.3 ± 4.2 kJ/mol, and Cr(Cp)(CO)2(PPh3)(H)(solution) = Cr(Cp)(CO)2(PPh3)(solution) + H(solution), 250.2 ± 4.2 kJ/mol Kiss, Zhang, et al., 1990. C depends on the solvent and on the reference electrode. The value given implies that the electrode potentials are referenced to ferrocene/ferricinium electrode; MS

C4H2FeO4 (g) = 2Hydrogen atom (g) + C4FeO4 (g)

By formula: C4H2FeO4 (g) = 2H (g) + C4FeO4 (g)

Quantity Value Units Method Reference Comment
Δr545.kJ/molESTMiller and Beauchamp, 1991Please also see Martinho Simões and Beauchamp, 1990. The reaction enthalpy was estimated from the activation enthalpy for thermal decomposition in solution, 109. ± 8. kJ/mol Pearson and Mauermann, 1982, yielding Fe(CO)4 and H2, and from the activation enthalpy of the oxidative addition of H2 to Fe(CO)4 in a rare gas matrix, ca. 0. kJ/mol Sweany, 1981, yielding Fe(CO)4H2. The enthalpy of formation relies on -440. ± 14. kJ/mol for the enthalpy of formation of Fe(CO)4(g); MS

Hydromanganese pentacarbonyl (g) = Hydrogen atom (g) + C5MnO5 (g)

By formula: C5HMnO5 (g) = H (g) + C5MnO5 (g)

Quantity Value Units Method Reference Comment
Δr245. ± 17.kJ/molPIMSMartinho Simões and Beauchamp, 1990The reaction enthalpy was derived from the appearance energy of Mn(CO)5(+), 993.8 ± 9.6 kJ/mol, using Mn(CO)5(H) as the neutral precursor, together with the adiabatic ionization energy of Mn(CO)5 radical, 749. ± 14. kJ/mol Martinho Simões and Beauchamp, 1990; MS

C3H10Ge (g) = C3H9Ge (g) + Hydrogen atom (g)

By formula: C3H10Ge (g) = C3H9Ge (g) + H (g)

Quantity Value Units Method Reference Comment
Δr334. ± 12.kJ/molICRBrinkman, Salomon, et al., 1995The reaction enthalpy was derived from the acidity of Ge(Me)3(H)(g), 1513. ± 12. kJ/mol, the electron affinity of Ge(Me)3(g), 133.5 ± 2.9 kJ/mol Brinkman, Salomon, et al., 1995, and the ionization energy of H(g), 1312.0 kJ/mol Lias, Bartmess, et al., 1988.; MS

C3H10Sn (g) = Hydrogen atom (g) + Trimethyltin (g)

By formula: C3H10Sn (g) = H (g) + C3H9Sn (g)

Quantity Value Units Method Reference Comment
Δr312. ± 11.kJ/molICRBrinkman, Salomon, et al., 1995The reaction enthalpy was derived from the acidity of Sn(Me)3(H)(g), 1460.2 ± 8.4 kJ/mol, the electron affinity of Sn(Me)3(g), 164.0 ± 6.3 kJ/mol Brinkman, Salomon, et al., 1995, and the ionization energy of H(g), 1312.0 kJ/mol Lias, Bartmess, et al., 1988.; MS

Germane (g) = Hydrogen atom (g) + Germyl radical (g)

By formula: H4Ge (g) = H (g) + H3Ge (g)

Quantity Value Units Method Reference Comment
Δr348.9 ± 8.4kJ/molPIMSBerkowitz, Ellison, et al., 1994Please also see Ruscic, Schwarz, et al., 1990. Value recommended in the critical survey Berkowitz, Ellison, et al., 1994.; MS
Δr<358.kJ/molPIMSRuscic, Schwarz, et al., 1990Temperature: 0 K. A value of 343. ± 8. kJ/mol is recommended in Ruscic, Schwarz, et al., 1990.; MS

e- + Hydrogen cation = Hydrogen atom

By formula: e- + H+ = H

Quantity Value Units Method Reference Comment
Δr1318.4kJ/molAcidWagman, Evans, et al., 1982gas phase; Using the "electron convention". Acid = H.; B
Quantity Value Units Method Reference Comment
Δr1313.8kJ/molH-TSWagman, Evans, et al., 1982gas phase; Using the "electron convention". Acid = H.; B

Germyl radical (g) = Hydrogen atom (g) + Germylene (g)

By formula: H3Ge (g) = H (g) + H2Ge (g)

Quantity Value Units Method Reference Comment
Δr>236.kJ/molPIMSRuscic, Schwarz, et al., 1990Temperature: 0 K. A value of 247. kJ/mol is recommended in Ruscic, Schwarz, et al., 1990.; MS

Germylene (g) = HGe (g) + Hydrogen atom (g)

By formula: H2Ge (g) = HGe (g) + H (g)

Quantity Value Units Method Reference Comment
Δr<288.kJ/molPIMSRuscic, Schwarz, et al., 1990Temperature: 0 K. A value of 277. kJ/mol is recommended in Ruscic, Schwarz, et al., 1990.; MS

HGe (g) = Hydrogen atom (g) + germanium (g)

By formula: HGe (g) = H (g) + Ge (g)

Quantity Value Units Method Reference Comment
Δr>225.kJ/molPIMSRuscic, Schwarz, et al., 1990Temperature: 0 K. A value of 264. kJ/mol is recommended in Ruscic, Schwarz, et al., 1990.; MS

H3Sb (g) = Hydrogen atom (g) + H2Sb (g)

By formula: H3Sb (g) = H (g) + H2Sb (g)

Quantity Value Units Method Reference Comment
Δr288.3 ± 2.1kJ/molPIMSBerkowitz, Ellison, et al., 1994Value recommended in the critical survey Berkowitz, Ellison, et al., 1994.; MS

C13H26IrP (solution) = C13H24IrP (solution) + 2Hydrogen atom (g)

By formula: C13H26IrP (solution) = C13H24IrP (solution) + 2H (g)

Quantity Value Units Method Reference Comment
Δr620.kJ/molESTNolan, Hoff, et al., 1987Please also see Stoutland, Bergman, et al., 1988.; MS

(CAS Reg. No. 952499-85-3 • 4294967295Hydrogen atom) + Hydrogen atom = CAS Reg. No. 952499-85-3

By formula: (CAS Reg. No. 952499-85-3 • 4294967295H) + H = CAS Reg. No. 952499-85-3

Quantity Value Units Method Reference Comment
Δr187. ± 18.kJ/molN/ACalvi, Andrews, et al., 2007gas phase; B

C13H26IrP (solution) = C13H25IrP (solution) + Hydrogen atom (g)

By formula: C13H26IrP (solution) = C13H25IrP (solution) + H (g)

Quantity Value Units Method Reference Comment
Δr305. ± 18.kJ/molPACNolan, Hoff, et al., 1987MS

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Reaction 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 evaluated as indicated in comments:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
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

View reactions leading to H+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)13.59844eVN/AN/AL
Quantity Value Units Method Reference Comment
Δf(+) ion1530.kJ/molN/AN/A 
Quantity Value Units Method Reference Comment
ΔfH(+) ion,0K1528.kJ/molN/AN/A 

Electron affinity determinations

EA (eV) Method Reference Comment
0.75497D-EAShiell, Hu, et al., 2000Given: 139714.8±1 cm-1 at 0K, or 399.465±0.003 kcal/mol; B
0.754189LPESLykke, Murray, et al., 1991Reported: 6082.99±0.15 cm-1, or 0.754195(18) eV; B
0.776 ± 0.020PDFeldman, 1970B

Ionization energy determinations

IE (eV) Method Reference Comment
13.59844EVALLide, 1992LL
13.599SKelly, 1987LBLHLM
13.61PEJonathan, Morris, et al., 1970RDSH
13.598SGarcia and Mack, 1965RDSH

De-protonation reactions

e- + Hydrogen cation = Hydrogen atom

By formula: e- + H+ = H

Quantity Value Units Method Reference Comment
Δr1318.4kJ/molAcidWagman, Evans, et al., 1982gas phase; Using the "electron convention". Acid = H.; B
Quantity Value Units Method Reference Comment
Δr1313.8kJ/molH-TSWagman, Evans, et al., 1982gas phase; Using the "electron convention". Acid = H.; B

Anion protonation reactions

Hydrogen anion + Hydrogen cation = Hydrogen

By formula: H- + H+ = H2

Quantity Value Units Method Reference Comment
Δr1675.3kJ/molN/AShiell, Hu, et al., 2000gas phase; Given: 139714.8±1 cm-1 at 0K, or 399.465±0.003 kcal/mol; B
Δr1675.3kJ/molN/APratt, McCormack, et al., 1992gas phase; 399.46±0.01 kcal/mol at 0K; 0.94 correction, Gurvich, Veyts, et al.; B
Δr1675.3kJ/molD-EALykke, Murray, et al., 1991gas phase; Reported: 6082.99±0.15 cm-1, or 0.754195(18) eV; B
Quantity Value Units Method Reference Comment
Δr1649.3 ± 0.42kJ/molH-TSShiell, Hu, et al., 2000gas phase; Given: 139714.8±1 cm-1 at 0K, or 399.465±0.003 kcal/mol; B
Δr1649.3kJ/molH-TSLykke, Murray, et al., 1991gas phase; Reported: 6082.99±0.15 cm-1, or 0.754195(18) eV; B

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry 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]

Parker, Handoo, et al., 1991
Parker, V.D.; Handoo, K.L.; Roness, F.; Tilset, M., J. Am. Chem. Soc., 1991, 113, 7493. [all data]

Tilset and Parker, 1989
Tilset, M.; Parker, V.D., J. Am. Chem. Soc., 1989, 111, 6711; ibid. 1990. [all data]

Kiss, Zhang, et al., 1990
Kiss, G.; Zhang, K.; Mukerjee, S.L.; Hoff, C.; Roper, G.C., J. Am. Chem. Soc., 1990, 112, 5657. [all data]

Billmers, Griffith, et al., 1986
Billmers, R.; Griffith, L.L.; Stein, S.E., J. Phys. Chem., 1986, 90, 517. [all data]

Sweany, Butler S.C., et al., 1981
Sweany, R.; Butler S.C.; Halpern, J., J. Organometal. Chem., 1981, 213, 487. [all data]

Miller and Beauchamp, 1991
Miller, A.E.S.; Beauchamp, J.L., J. Am. Chem. Soc., 1991, 113, 8765. [all data]

Martinho Simões and Beauchamp, 1990
Martinho Simões, J.A.; Beauchamp, J.L., Chem. Rev., 1990, 90, 629. [all data]

Pearson and Mauermann, 1982
Pearson, R.G.; Mauermann, H., J. Am. Chem. Soc., 1982, 104, 500. [all data]

Sweany, 1981
Sweany, R.L., J. Am. Chem. Soc., 1981, 103, 2410. [all data]

Brinkman, Salomon, et al., 1995
Brinkman, E.A.; Salomon, K.; Tumas, W.; Brauman, J.I., Electron affinities and gas-phase acidities of organogermanium and organotin compounds, J. Am. Chem. Soc., 1995, 117, 17, 4905, https://doi.org/10.1021/ja00122a022 . [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-Phase Ion and Neutral Thermochemistry, J. Phys. Chem. Ref. Data, 1988, 17, Suppl. 1. [all data]

Berkowitz, Ellison, et al., 1994
Berkowitz, J.; Ellison, G.B.; Gutman, D., Three methods to measure RH bond energies, J. Phys. Chem., 1994, 98, 2744. [all data]

Ruscic, Schwarz, et al., 1990
Ruscic, B.; Schwarz, M.; Berkowitz, J., Photoionization studies of GeHn(n = 2-4), J. Chem. Phys., 1990, 92, 1865. [all data]

Wagman, Evans, et al., 1982
Wagman, D.D.; Evans, W.H.; Parker, V.B.; Schumm, R.H.; Halow, I.; Bailey, S.M.; Churney, K.L.; Nuttall, R.L., The NBS Tables of Chemical Thermodynamic Properties (NBS Tech Note 270), J. Phys. Chem. Ref. Data, Supl. 1, 1982, 11. [all data]

Nolan, Hoff, et al., 1987
Nolan, S.P.; Hoff, C.D.; Stoutland, P.O.; Newman, L.J.; Buchanan, J.M.; Bergman, R.G.; Yang, G.K.; Peters, K.S., J. Am. Chem. Soc., 1987, 109, 3143. [all data]

Stoutland, Bergman, et al., 1988
Stoutland, P.O.; Bergman, R.G.; Nolan, S.P.; Hoff, C.D., Polyhedron, 1988, 7, 1429. [all data]

Calvi, Andrews, et al., 2007
Calvi, R.M.D.; Andrews, D.H.; Lineberger, W.C., Negative ion photoelectron spectroscopy of copper hydrides, Chem. Phys. Lett., 2007, 442, 1-3, 12-16, https://doi.org/10.1016/j.cplett.2007.05.060 . [all data]

Shiell, Hu, et al., 2000
Shiell, R.C.; Hu, X.K.; Hu, Q.C.J.; Hepburn, J.W., Threshold Ion-pair Production spectroscopy (TIPPS) of H2 and D2, Faraday Disc. Chem. Soc., 2000, 115, 331, https://doi.org/10.1039/a909428h . [all data]

Lykke, Murray, et al., 1991
Lykke, K.R.; Murray, K.K.; Lineberger, W.C., Threshold Photodetachment of H-, Phys. Rev. A, 1991, 43, 11, 6104, https://doi.org/10.1103/PhysRevA.43.6104 . [all data]

Feldman, 1970
Feldman, D., Photoablosung von Elektronen bei einigen Stabilen Negativen Ionen, Z. Naturfor., 1970, 25A, 621. [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]

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

Jonathan, Morris, et al., 1970
Jonathan, N.; Morris, A.; Smith, D.J.; Ross, K.J., Photoelectron spectra of ground state atomic hydrogen, nitrogen and oxygen, Chem. Phys. Lett., 1970, 7, 497. [all data]

Garcia and Mack, 1965
Garcia, J.D.; Mack, J.E., Energy level and line tables for one-electron atomic spectra, J. Opt. Soc. Am., 1965, 55, 654. [all data]

Pratt, McCormack, et al., 1992
Pratt, S.T.; McCormack, E.F.; Dehmer, J.L.; Dehmer, P.M., Field-Induced Ion-Pair Formation in Molecular Hydrogen, Phys. Rev. Lett., 1992, 68, 5, 584, https://doi.org/10.1103/PhysRevLett.68.584 . [all data]

Gurvich, Veyts, et al.
Gurvich, L.V.; Veyts, I.V.; Alcock, C.B., Hemisphere Publishing, NY, 1989, V. 1 2, Thermodynamic Properties of Individual Substances, 4th Ed. [all data]


Notes

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