o-Xylene
- Formula: C8H10
- Molecular weight: 106.1650
- IUPAC Standard InChIKey: CTQNGGLPUBDAKN-UHFFFAOYSA-N
- CAS Registry Number: 95-47-6
- 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. - Isotopologues:
- Other names: Benzene, 1,2-dimethyl-; o-Dimethylbenzene; o-Methyltoluene; o-Xylol; 1,2-Dimethylbenzene; 1,2-Xylene; 3,4-Xylene; ortho-Xylene; NSC 60920; 2-Methyltoluene; UN 1307; 1,2-dimethyl-benzene ( o-xylene)
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Gas phase thermochemistry data
Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), 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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | 19.0 ± 1.1 | kJ/mol | Ccb | Prosen, Gilmont, et al., 1945 | Hf by Prosen, Johnson, et al., 1946; ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°gas | 353.6 ± 1.3 | J/mol*K | N/A | Pitzer K.S., 1943 | GT |
Constant pressure heat capacity of gas
Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
96.05 | 200. | Draeger, 1985 | Discrepancies with other statistically calculated values of S(T) and Cp(T) [ Pitzer K.S., 1943, Taylor W.J., 1946, Hastings S.H., 1957, Chao J., 1984] do not exceed 1.5 J/mol*K.; GT |
122.9 | 273.15 | ||
132.5 ± 0.4 | 298.15 | ||
133.2 | 300. | ||
171.6 | 400. | ||
206.0 | 500. | ||
235.1 | 600. | ||
259.5 | 700. | ||
280.0 | 800. | ||
297.4 | 900. | ||
312.2 | 1000. | ||
324.9 | 1100. | ||
335.8 | 1200. | ||
345.2 | 1300. | ||
353.3 | 1400. | ||
360.3 | 1500. |
Constant pressure heat capacity of gas
Cp,gas (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
168.2 ± 1.7 | 393. | Taylor W.J., 1946 | Please also see Pitzer K.S., 1943.; GT |
182.0 ± 1.7 | 428. | ||
192.5 ± 2.1 | 463. |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), 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:
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
View reactions leading to C8H10+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 8.56 ± 0.04 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 796.0 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 768.3 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Proton affinity at 298K
Proton affinity (kJ/mol) | Reference | Comment |
---|---|---|
791.2 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
793.5 ± 1.7 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Gas basicity at 298K
Gas basicity (review) (kJ/mol) | Reference | Comment |
---|---|---|
765.3 | Aue, Guidoni, et al., 2000 | Experimental literature data re-evaluated by the authors using ab initio protonation entropies; MM |
772.1 ± 2.2 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Protonation entropy at 298K
Protonation entropy (J/mol*K) | Reference | Comment |
---|---|---|
36.9 | Fernandez, Jennings, et al., 1989 | T = 370 - 750K; Reference Sprot(CH3)2O = 16.5 J/mol K in Hunter and Lias, 1998 needs to be re-evaluated; MM |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
8.56 ± 0.01 | EQ | Lias and Ausloos, 1978 | LLK |
8.85 ± 0.05 | EI | Loudon and Mazengo, 1974 | LLK |
8.45 ± 0.02 | PE | Maier and Turner, 1973 | LLK |
8.70 | CTS | Kobayashi, Kobayashi, et al., 1973 | LLK |
8.6 ± 0.1 | EI | Gilbert, Leach, et al., 1973 | LLK |
8.61 | CTS | Pitt, 1970 | RDSH |
8.555 | PI | Bralsford, Harris, et al., 1960 | RDSH |
8.56 ± 0.01 | PI | Watanabe, 1957 | RDSH |
8.56 ± 0.02 | PI | Vilesov and Terenin, 1957 | RDSH |
8.58 ± 0.01 | S | Hammond, Price, et al., 1950 | RDSH |
8.56 | PE | Howell, Goncalves, et al., 1984 | Vertical value; LBLHLM |
8.57 ± 0.03 | PE | Heilbronner, Hoshi, et al., 1976 | Vertical value; LLK |
8.57 | PE | Brogli, Giovannini, et al., 1973 | Vertical value; LLK |
8.75 ± 0.03 | PE | Klessinger, 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C7H7+ | 11.8 ± 0.2 | CH3 | EI | Loudon and Mazengo, 1974 | LLK |
C7H7+ | 11.10 ± 0.05 | CH3 | PI | Akopyan and Vilesov, 1968 | RDSH |
C7H7+ | 11.2 ± 0.1 | CH3 | EI | Nounou, 1966 | RDSH |
C8H9+ | 12.1 ± 0.2 | H | EI | Loudon and Mazengo, 1974 | LLK |
C8H9+ | 11.30 ± 0.05 | H | PI | Akopyan and Vilesov, 1968 | RDSH |
Mass spectrum (electron ionization)
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 by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | NIST Mass Spectrometry Data Center, 1998. |
NIST MS number | 291483 |
References
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Prosen, Gilmont, et al., 1945
Prosen, E.J.; Gilmont, R.; Rossini, F.D.,
Heats of combustion of benzene, toluene, ethyl-benzene, o-xylene, m-xylene, p-xylene, n-propylbenzene, and styrene,
J. Res. NBS, 1945, 34, 65-70. [all data]
Prosen, Johnson, et al., 1946
Prosen, E.J.; Johnson, W.H.; Rossini, F.D.,
Heats of combustion and formation at 25°C of the alkylbenzenes through C10H14, and of the higher normal monoalkylbenzenes,
J. Res. NBS, 1946, 36, 455-461. [all data]
Pitzer K.S., 1943
Pitzer K.S.,
The thermodynamics and molecular structure of benzene and its methyl derivatives,
J. Am. Chem. Soc., 1943, 65, 803-829. [all data]
Draeger, 1985
Draeger, J.A.,
The methylbenzenes II. Fundamental vibrational shifts, statistical thermodynamic functions, and properties of formation,
J. Chem. Thermodyn., 1985, 17, 263-275. [all data]
Taylor W.J., 1946
Taylor W.J.,
Heats, equilibrium constants, and free energies of formation of the alkylbenzenes,
J. Res. Nat. Bur. Stand., 1946, 37, 95-122. [all data]
Hastings S.H., 1957
Hastings S.H.,
Thermodynamic properties of selected methylbenzenes from 0 to 1000 K,
J. Phys. Chem., 1957, 61, 730-735. [all data]
Chao J., 1984
Chao J.,
Chemical thermodynamic properties of toluene, o-, m- and p-xylenes,
Thermochim. Acta, 1984, 72, 323-334. [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]
Aue, Guidoni, et al., 2000
Aue, D.H.; Guidoni, M.; Betowski, L.D.,
Ab initio calculated gas-phase basicities of polynuclear aromatic hydrocarbons,
Int. J. Mass Spectrom., 2000, 201, 283. [all data]
Fernandez, Jennings, et al., 1989
Fernandez, T.; Jennings, K.R.; Mason, R.S.,
Gas-phase proton transfer reactions in xylene-dimethyl ether mixtures,
J. Chem. Soc. Faraday Trans. 2, 1989, 85, 1813. [all data]
Lias and Ausloos, 1978
Lias, S.G.; Ausloos, P.J.,
eIonization energies of organic compounds by equilibrium measurements,
J. Am. Chem. Soc., 1978, 100, 6027. [all data]
Loudon and Mazengo, 1974
Loudon, A.G.; Mazengo, R.Z.,
Steric strain and electron-impact. The behaviour of some n, n'-dimethyl- 1,1-binaphthyls, some n, n'-dimethylbiphenyls and model compounds,
Org. Mass Spectrom., 1974, 8, 179. [all data]
Maier and Turner, 1973
Maier, J.P.; Turner, D.W.,
Steric inhibition of resonance studied by molecular photoelectron spectroscopy. Part 2. Phenylethylenes,
J. Chem. Soc. Faraday Trans. 2, 1973, 69, 196. [all data]
Kobayashi, Kobayashi, et al., 1973
Kobayashi, H.; Kobayashi, M.; Kaizu, Y.,
Molecular complexes of arenetricarbonylchromium,
Bull. Chem. Soc. Jpn., 1973, 46, 3109. [all data]
Gilbert, Leach, et al., 1973
Gilbert, J.R.; Leach, W.P.; Miller, J.R.,
Ionisation appearance potential measurements in arene chromium tricarbonyls,
J. Organomet. Chem., 1973, 49, 219. [all data]
Pitt, 1970
Pitt, C.G.,
Hyperconjugation: An alternative to the concept of the pπ-dπ bond in Group IV chemistry,
J. Organomet. Chem., 1970, 23, 35. [all data]
Bralsford, Harris, et al., 1960
Bralsford, R.; Harris, P.V.; Price, W.C.,
The effect of fluorine on the electronic spectra and ionization potentials of molecules,
Proc. Roy. Soc. (London), 1960, A258, 459. [all data]
Watanabe, 1957
Watanabe, K.,
Ionization potentials of some molecules,
J. Chem. Phys., 1957, 26, 542. [all data]
Vilesov and Terenin, 1957
Vilesov, F.I.; Terenin, A.N.,
The photoionization of the vapors of certain organic compounds,
Dokl. Akad. Nauk SSSR, 1957, 115, 744, In original 539. [all data]
Hammond, Price, et al., 1950
Hammond, V.J.; Price, W.C.; Teegan, J.P.; Walsh, A.D.,
The absorption spectra of some substituted benzenes and naphthalenes in the vacuum ultra-violet,
Faraday Discuss. Chem. Soc., 1950, 9, 53. [all data]
Howell, Goncalves, et al., 1984
Howell, J.O.; Goncalves, J.M.; Amatore, C.; Klasinc, L.; Wightman, R.M.; Kochi, J.K.,
Electron transfer from aromatic hydrocarbons and their π-complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials,
J. Am. Chem. Soc., 1984, 106, 3968. [all data]
Heilbronner, Hoshi, et al., 1976
Heilbronner, E.; Hoshi, T.; von Rosenberg, J.L.; Hafner, K.,
Alkyl-induced, natural hypsochromic shifts of the 2A←2X and 2B←2X transitions of azulene and naphthalene radical cations,
Nouv. J. Chim., 1976, 1, 105. [all data]
Brogli, Giovannini, et al., 1973
Brogli, F.; Giovannini, E.; Heilbronner, E.; Schurter, R.,
Die photoelektronen spektren der benzocycloalkene,
Chem. Ber., 1973, 106, 961. [all data]
Klessinger, 1972
Klessinger, M.,
Ionization potentials of substituted benzenes,
Angew. Chem. Int. Ed. Engl., 1972, 11, 525. [all data]
Akopyan and Vilesov, 1968
Akopyan, M.E.; Vilesov, F.I.,
Mass-spectrometric investigation of the photo-ionization of benzene and its methyl derivatives,
Khim. Vysokikh Energ., 1968, 2, 107, In original 89. [all data]
Nounou, 1966
Nounou, P.,
Etude des composes aromatiques par spectrometrie de masse. I. Mesure des potentials d'ionisation et d'apparition par la methode du potential retardateur et interpretation des courbes d'ionisation differentielle,
J. Chim. Phys., 1966, 63, 994. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References
- Symbols used in this document:
AE Appearance energy Cp,gas Constant pressure heat capacity of gas IE (evaluated) Recommended ionization energy S°gas Entropy of gas at standard conditions ΔfH°gas Enthalpy of formation of gas at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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