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Urea

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Gas phase ion energetics 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
MM - Michael M. Meot-Ner (Mautner)
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Proton affinity at 298K

Proton affinity (kJ/mol) Reference Comment
868.4 ± 2.5Zheng and Cooks, 2002MM
873.5 ± 5.0Wang, Ma, et al., 1998m-bromoaniline; p-fluorobenzamide; MM
873.5 ± 5.0Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Gas basicity at 298K

Gas basicity (review) (kJ/mol) Reference Comment
838.7 ± 3.0Zheng and Cooks, 2002MM
846.1 ± 5.0Wang, Ma, et al., 1998m-bromoaniline; p-fluorobenzamide; MM
841.6 ± 5.0Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Protonation entropy at 298K

Protonation entropy (J/mol*K) Reference Comment
9.4Zheng and Cooks, 2002MM
-1.9Wang, Ma, et al., 1998T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM

Ionization energy determinations

IE (eV) Method Reference Comment
9.7PEDebies and Rabalais, 1974LLK
10.27 ± 0.05EIBaldwin, Kirkien-Konasiewicz, et al., 1966RDSH
9.8PEBieri, Asbrink, et al., 1982Vertical value; LBLHLM
10.28PEDougherty, Wittel, et al., 1976Vertical value; LLK
10.33PEMines and Thompson, 1975Vertical value; LLK
10.15PEMeeks, Arnett, et al., 1975Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CH2NO+12.90?EILoudon and Webb, 1977LLK

De-protonation reactions

CH3N2O- + Hydrogen cation = Urea

By formula: CH3N2O- + H+ = CH4N2O

Quantity Value Units Method Reference Comment
Deltar1514. ± 12.kJ/molCIDCMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Deltar1517. ± 11.kJ/molG+TSTaft, 1987gas phase; value altered from reference due to change in acidity scale; B
Deltar1495. ± 8.8kJ/molEIAEMuftakhov, Vasil'ev, et al., 1999gas phase; B
Quantity Value Units Method Reference Comment
Deltar1488. ± 13.kJ/molH-TSMa, Wang, et al., 1998gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B
Deltar1487. ± 10.kJ/molIMRETaft, 1987gas phase; value altered from reference due to change in acidity scale; B

References

Go To: Top, 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.

Zheng and Cooks, 2002
Zheng, X.; Cooks, R.G., Thermochemical determinations by the kinetic method with direct entropy corrrection, J. Phys. Chem. A, 2002, 106, 9939. [all data]

Wang, Ma, et al., 1998
Wang, F.; Ma, S.G.; Zhang, D.X.; Cooks, R.G., Proton affinity and gas-phase basicity of urea, J. Phys. Chem. A., 1998, 102, 2988. [all data]

Debies and Rabalais, 1974
Debies, T.P.; Rabalais, J.W., Electronic structure of amino acids and ureas, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 315. [all data]

Baldwin, Kirkien-Konasiewicz, et al., 1966
Baldwin, M.; Kirkien-Konasiewicz, A.; Loudon, A.G.; Maccoll, A.; Smith, D., Localised or delocalised charges in molecule-ions?, Chem. Commun., 1966, 574. [all data]

Bieri, Asbrink, et al., 1982
Bieri, G.; Asbrink, L.; Von Niessen, W., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1982, 27, 129. [all data]

Dougherty, Wittel, et al., 1976
Dougherty, D.; Wittel, K.; Meeks, J.; McGlynn, S.P., Photoelectron spectroscopy of carbonyls. Ureas, uracils, and thymine, J. Am. Chem. Soc., 1976, 98, 3815. [all data]

Mines and Thompson, 1975
Mines, G.W.; Thompson, H.W., The photoelectron spectra of amides, thioamides, ureas and thioureas, Spectrochim. Acta, 1975, 31, 137. [all data]

Meeks, Arnett, et al., 1975
Meeks, J.L.; Arnett, J.F.; Larson, D.B.; McGlynn, S.P., Photoelectron spectroscopy of carbonyls. Urea, oxamide, oxalic acid and oxamic acid, J. Am. Chem. Soc., 1975, 97, 3905. [all data]

Loudon and Webb, 1977
Loudon, A.G.; Webb, K.S., The nature of the [C2H6N]+ and [CH4N]+ ions formed by electron impact on methylated formamides, acetamides, ureas, thioureas and hexamethylphosphoramide, Org. Mass Spectrom., 1977, 12, 283. [all data]

Ma, Wang, et al., 1998
Ma, S.G.; Wang, F.; Cooks, R.G., Gas-phase acidity of urea, J. Mass Spectrom., 1998, 33, 10, 943-949, https://doi.org/10.1002/(SICI)1096-9888(1998100)33:10<943::AID-JMS703>3.0.CO;2-B . [all data]

Taft, 1987
Taft, R.W., The Nature and Analysis of Substitutent Electronic Effects, Personal communication. See also Prog. Phys. Org. Chem., 1987, 16, 1. [all data]

Muftakhov, Vasil'ev, et al., 1999
Muftakhov, M.V.; Vasil'ev, Y.V.; Mazunov, V.A., Determination of electron affinity of carbonyl radicals by means of negative ion mass spectrometry, Rapid Commun. Mass Spectrom., 1999, 13, 12, 1104-1108, https://doi.org/10.1002/(SICI)1097-0231(19990630)13:12<1104::AID-RCM619>3.0.CO;2-C . [all data]


Notes

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