Benzyl radical
- Formula: C7H7
- Molecular weight: 91.1305
- IUPAC Standard InChIKey: SLRMQYXOBQWXCR-UHFFFAOYSA-N
- CAS Registry Number: 2154-56-5
- 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:
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- Options:
Data at NIST subscription sites:
NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.
Gas phase ion energetics data
Go To: Top, 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:
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess
View reactions leading to C7H7+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 7.242 ± 0.006 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 198.7 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 191.4 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
ΔfH°(+) ion | 215. ± 1.6 | kcal/mol | N/A | N/A | |
Quantity | Value | Units | Method | Reference | Comment |
ΔfH(+) ion,0K | 219.6 ± 1.2 | kcal/mol | N/A | N/A |
Electron affinity determinations
EA (eV) | Method | Reference | Comment |
---|---|---|---|
0.9120 ± 0.0060 | LPES | Gunion, Gilles, et al., 1992 | Kim, Wenthold, et al., 1999, with LN2 cooling of the ion, gives the same EA; B |
0.979 ± 0.093 | D-EA | Bartmess, Scott, et al., 1979 | value altered from reference due to change in acidity scale; B |
0.863 ± 0.013 | LPD | Drzaic and Brauman, 1984 | B |
0.885 ± 0.065 | LPD | Richardson, Stephenson, et al., 1975 | B |
2.350 ± 0.069 | SI | Failes, Joyce, et al., 1976 | The Magnetron method, lacking mass analysis, is not considered reliable.; B |
1.0841 | SI | Page, 1972 | The Magnetron method, lacking mass analysis, is not considered reliable.; B |
0.758873 | SI | Page and Goode, 1969 | The Magnetron method, lacking mass analysis, is not considered reliable.; B |
0.7979 | SI | Gaines and Page, 1968 | The Magnetron method, lacking mass analysis, is not considered reliable.; B |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
7.236 | LS | Im and Bernstein, 1991 | T = 0K; LL |
7.2488 ± 0.0006 | TE | Eiden, Weinhold, et al., 1991 | T = 0K; LL |
7.2477 ± 0.0017 | LS | Eiden and Weisshaar, 1991 | T = 0K; LL |
7.2 | DER | Griller and Lossing, 1981 | LLK |
7.20 ± 0.02 | PE | Houle and Beauchamp, 1978 | LLK |
≤7.27 ± 0.03 | EI | Lossing, 1971 | LLK |
7.63 | PI | Elder and Parr, 1969 | RDSH |
7.5 ± 0.1 | S | Akopyan and Vilesov, 1966 | RDSH |
7.76 ± 0.08 | EI | Harrison, Kebarle, et al., 1961 | RDSH |
7.43 ± 0.06 | PE | Koenig, Snell, et al., 1976 | Vertical value; LLK |
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.
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]
Gunion, Gilles, et al., 1992
Gunion, R.F.; Gilles, M.K.; Polak, M.L.; Lineberger, W.C.,
Ultraviolet Photoelectron Spectroscopy of the Phenide, Benzyl, and Phenoxide Anions.,
Int. J. Mass Spectrom. Ion Proc., 1992, 117, 601, https://doi.org/10.1016/0168-1176(92)80115-H
. [all data]
Kim, Wenthold, et al., 1999
Kim, J.B.; Wenthold, P.G.; Lineberger, W.C.,
Ultraviolet photoelectron spectroscopy of o-, m-, and p-halobenzyl anions,
J. Phys. Chem. A, 1999, 103, 50, 10833-10841, https://doi.org/10.1021/jp992817o
. [all data]
Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr.,
The gas phase acidity scale from methanol to phenol,
J. Am. Chem. Soc., 1979, 101, 6047. [all data]
Drzaic and Brauman, 1984
Drzaic, P.S.; Brauman, J.I.,
A determination of the singlet-triplet splitting in phenylnitrene via photoelectron detachment,
J. Phys. Chem., 1984, 88, 5285. [all data]
Richardson, Stephenson, et al., 1975
Richardson, J.H.; Stephenson, L.M.; Brauman, J.I.,
Photodetachment of electrons from large molecular systems: Benzyl anion. An upper Limitlto the electron affinity of C6H5CH2,
J. Chem. Phys., 1975, 63, 74. [all data]
Failes, Joyce, et al., 1976
Failes, R.L.; Joyce, J.T.; Walton, E.C.,
The behaviour of some dimethyl and trimethyl substituted pyridines in the magnetron,
J. Phys. D: Appl. Phys., 1976, 9, 1543. [all data]
Page, 1972
Page, F.M.,
Experimental determination of the electron affinities of inorganic radicals,
Adv. Chem. Ser., 1972, 36, 68. [all data]
Page and Goode, 1969
Page, F.M.; Goode, G.C.,
Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]
Gaines and Page, 1968
Gaines, A.F.; Page, F.M.,
The Stabilities of Negative Ions.I. The Methyl-, Diphenylmethyl, and Triphenylmethyl Negative Ions,
Int. J. Mass Spectrom. Ion Phys., 1968, 1, 4-5, 315, https://doi.org/10.1016/0020-7381(68)85008-9
. [all data]
Im and Bernstein, 1991
Im, H.S.; Bernstein, E.R.,
Mass resolved excitation spectroscopy of radicals: benzyl and phenylnitrene,
J. Chem. Phys., 1991, 95, 6326. [all data]
Eiden, Weinhold, et al., 1991
Eiden, G.C.; Weinhold, F.; Weisshar, J.C.,
Photoelectron spectroscopy of free radicals with cm-1 resolution: The benzyl cation,
J. Chem. Phys., 1991, 95, 8665. [all data]
Eiden and Weisshaar, 1991
Eiden, G.C.; Weisshaar, J.C.,
Adiabatic ionization potential of benzyl radical by two-color resonant two-photon ionization,
J. Phys. Chem., 1991, 95, 6194. [all data]
Griller and Lossing, 1981
Griller, D.; Lossing, F.P.,
On the thermochemistry of α-aminoalkyl radicals,
J. Am. Chem. Soc., 1981, 103, 1586. [all data]
Houle and Beauchamp, 1978
Houle, F.A.; Beauchamp, J.L.,
Detection and investigation of allyl and benzyl radicals by photoelectron spectroscopy,
J. Am. Chem. Soc., 1978, 100, 3290. [all data]
Lossing, 1971
Lossing, F.P.,
Free radicals by mass spectrometry. XLIII. Ionization potentials and ionic heats of formation for vinyl, allyl, and benzyl radicals,
Can. J. Chem., 1971, 49, 357. [all data]
Elder and Parr, 1969
Elder, F.A.; Parr, A.C.,
Photoionization of the cycloheptatrienyl radical,
J. Chem. Phys., 1969, 50, 1027. [all data]
Akopyan and Vilesov, 1966
Akopyan, M.E.; Vilesov, F.I.,
A mass-spectrometric study of the photo-ionisation of benzene derivatives at wavelengths up to 885 A,
Zh. Fiz. Khim., 1966, 40, 125, In original 63. [all data]
Harrison, Kebarle, et al., 1961
Harrison, A.G.; Kebarle, P.; Lossing, F.P.,
Free radicals by mass spectrometry. XXI. The ionization potentials of some meta and para substituted benzyl radicals,
J. Am. Chem. Soc., 1961, 83, 777. [all data]
Koenig, Snell, et al., 1976
Koenig, T.; Snell, W.; Chang, J.C.,
The He(I) photoelectron spectra of benzyl and α-cyanoisopropyl radicals,
Tetrahedron Lett., 1976, 50, 4569. [all data]
Notes
Go To: Top, Gas phase ion energetics data, References
- Symbols used in this document:
EA Electron affinity IE (evaluated) Recommended ionization energy ΔfH(+) ion,0K Enthalpy of formation of positive ion at 0K - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.