Urea
- Formula: CH4N2O
- Molecular weight: 60.0553
- IUPAC Standard InChI: InChI=1S/CH4N2O/c2-1(3)4/h(H4,2,3,4)
- IUPAC Standard InChIKey: XSQUKJJJFZCRTK-UHFFFAOYSA-N
- CAS Registry Number: 57-13-6
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: Carbamide; Carbamimidic acid; Carbonyldiamide; Isourea; Pseudourea; Urea-13C; Ureaphil; Ureophil; Urevert; UR; (NH2)2CO; Carbonyl Diamine; Alphadrate; Aquacare; Aquadrate; B-I-K; Calmurid; Carbaderm; Keratinamin; NCI-C02119; Pastaron; Prespersion, 75 urea; Ultra Mide; Urepearl; Mocovina; Supercel 3000; Varioform II; Benural 70; Harnstoff; Basodexan; Bubber shet; Elaqua xx; Hyanit; Nutraplus; Onychomal; NSC 34375; Uroderm; Panafil (Salt/Mix); Cerovel (Salt/Mix); component of Artra Ashy Skin Cream (Salt/Mix)
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Reaction thermochemistry data
Go To: Top, 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:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
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
CH3N2O- + =
By formula: CH3N2O- + H+ = CH4N2O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 361.8 ± 2.8 | kcal/mol | CIDC | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
| ΔrH° | 362.5 ± 2.6 | kcal/mol | G+TS | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrH° | 357.4 ± 2.1 | kcal/mol | EIAE | Muftakhov, Vasil'ev, et al., 1999 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 355.7 ± 3.2 | kcal/mol | H-TS | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
| ΔrG° | 355.5 ± 2.5 | kcal/mol | IMRE | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
+
=
By formula: CH4N2O + C4H4O2 = N-(aminocarbonyl)-3-oxobutyramide
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | -25.43 | kcal/mol | Kin | Lopatin, Popov, et al., 1992 | liquid phase; solvent: Solution; ALS |
6 =
+ 3
+ 6
By formula: 6CH4N2O = C3H6N6 + 3CO2 + 6H3N
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 112.2 | kcal/mol | Eqk | Rukevich and Zagranichnyi, 1971 | liquid phase; ALS |
Gas phase ion energetics data
Go To: Top, 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 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 (kcal/mol) | Reference | Comment |
|---|---|---|
| 207.6 ± 0.60 | Zheng and Cooks, 2002 | MM |
| 208.8 ± 1.2 | Wang, Ma, et al., 1998 | m-bromoaniline; p-fluorobenzamide; MM |
| 208.8 ± 1.2 | Wang, Ma, et al., 1998 | T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM |
Gas basicity at 298K
| Gas basicity (review) (kcal/mol) | Reference | Comment |
|---|---|---|
| 200.5 ± 0.72 | Zheng and Cooks, 2002 | MM |
| 202.2 ± 1.2 | Wang, Ma, et al., 1998 | m-bromoaniline; p-fluorobenzamide; MM |
| 201.1 ± 1.2 | Wang, Ma, et al., 1998 | T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM |
Protonation entropy at 298K
| Protonation entropy (cal/mol*K) | Reference | Comment |
|---|---|---|
| 2.2 | Zheng and Cooks, 2002 | MM |
| -0.45 | Wang, Ma, et al., 1998 | T = T(eff) = 410-560 KK; Acrylamide;m-Bromoaniline; MM |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 9.7 | PE | Debies and Rabalais, 1974 | LLK |
| 10.27 ± 0.05 | EI | Baldwin, Kirkien-Konasiewicz, et al., 1966 | RDSH |
| 9.8 | PE | Bieri, Asbrink, et al., 1982 | Vertical value; LBLHLM |
| 10.28 | PE | Dougherty, Wittel, et al., 1976 | Vertical value; LLK |
| 10.33 | PE | Mines and Thompson, 1975 | Vertical value; LLK |
| 10.15 | PE | Meeks, Arnett, et al., 1975 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| CH2NO+ | 12.90 | ? | EI | Loudon and Webb, 1977 | LLK |
De-protonation reactions
CH3N2O- + =
By formula: CH3N2O- + H+ = CH4N2O
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 361.8 ± 2.8 | kcal/mol | CIDC | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
| ΔrH° | 362.5 ± 2.6 | kcal/mol | G+TS | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
| ΔrH° | 357.4 ± 2.1 | kcal/mol | EIAE | Muftakhov, Vasil'ev, et al., 1999 | gas phase; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 355.7 ± 3.2 | kcal/mol | H-TS | Ma, Wang, et al., 1998 | gas phase; H and S (20.5±1.8 eu) directly from kinetic method; B |
| ΔrG° | 355.5 ± 2.5 | kcal/mol | IMRE | Taft, 1987 | gas phase; value altered from reference due to change in acidity scale; B |
References
Go To: Top, 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.
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]
Lopatin, Popov, et al., 1992
Lopatin, E.B.; Popov, V.V.; Epshtein, N.A.; Mikhaleva, L.M.; Makarov, Yu.N.,
Kinetic and thermochemical characteristics of diketene-based reactions,
Khim.-Farm. Zh., 1992, 26, 76-78. [all data]
Rukevich and Zagranichnyi, 1971
Rukevich, O.S.; Zagranichnyi, V.I.,
Equilibrium in the reaction of melamine formation from urea,
J. Anal. Chem. USSR, 1971, 44, 1616-1620. [all data]
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]
Notes
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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