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Isocyanic acid


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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

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

Quantity Value Units Method Reference Comment
IE (evaluated)11.595 ± 0.005eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)753.kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity718.8kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
11.595 ± 0.005PIRuscic and Berkowitz, 1994LL
11.62 ± 0.02PECradock, Ebsworth, et al., 1972LLK
11.60 ± 0.01PERowland, Eland, et al., 1968RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CHO+15.52NEICompernolle, 1975LLK
CHO+15.76 ± 0.15NEIBogan and Hand, 1971LLK
CNO+<=16.532HPIRuscic and Berkowitz, 1994LL
CNO+16.66 ± 0.15HEIBogan and Hand, 1971LLK
CNO+<=16.1HEIRowland, Eland, et al., 1968RDSH
NH+17.26 ± 0.15COEIBogan and Hand, 1971LLK
NH+<=17.7COEIRowland, Eland, et al., 1968RDSH
NO+15.76 ± 0.15?EIBogan and Hand, 1971LLK

De-protonation reactions

CNO- + Hydrogen cation = Isocyanic acid

By formula: CNO- + H+ = CHNO

Quantity Value Units Method Reference Comment
Deltar1427.5 ± 2.6kJ/molD-EABradforth, Kim, et al., 1993gas phase; D-EA cycle requires a DH ca 4 kcal/mol weaker; B
Deltar1442. ± 8.8kJ/molG+TSWight and Beauchamp, 1980gas phase; B
Quantity Value Units Method Reference Comment
Deltar1400.6 ± 3.0kJ/molH-TSBradforth, Kim, et al., 1993gas phase; D-EA cycle requires a DH ca 4 kcal/mol weaker; B
Deltar1415. ± 8.4kJ/molIMREWight and Beauchamp, 1980gas phase; 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.

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]

Ruscic and Berkowitz, 1994
Ruscic, B.; Berkowitz, J., The H-NCO bond energy and Hf(NCO) from photoionization mass spectrometric studies of HNCO and NCO, J. Chem. Phys., 1994, 100, 4498. [all data]

Cradock, Ebsworth, et al., 1972
Cradock, S.; Ebsworth, E.A.V.; Murdoch, J.D., Photoelectron spectra of some Group 4 pseudohalides and related compounds, J. Chem. Soc. Faraday Trans. 2, 1972, 68, 86. [all data]

Rowland, Eland, et al., 1968
Rowland, C.G.; Eland, J.H.D.; Danby, C.J., A spin-forbidden predissociation in the mass spectrum of isocyanic acid, Chem. Commun., 1968, 1535. [all data]

Compernolle, 1975
Compernolle, F., Mass spectrum and heat of formation of isocyanic acid. Production of [HCO]+ from discrete electronic state of molecular ion, Org. Mass Spectrom., 1975, 10, 289. [all data]

Bogan and Hand, 1971
Bogan, D.J.; Hand, C.W., Mass spectrum of isocyanic acid, J. Phys. Chem., 1971, 75, 1532. [all data]

Bradforth, Kim, et al., 1993
Bradforth, S.E.; Kim, E.H.; Arnold, D.W.; Neumark, D.M., Photoelectron Spectroscopy of CN-, NCO-, and NCS-, J. Chem. Phys., 1993, 98, 2, 800, https://doi.org/10.1063/1.464244 . [all data]

Wight and Beauchamp, 1980
Wight, C.A.; Beauchamp, J.L., Acidity, basicity, and ion/molecule reactions of isocyanic acid in the gas phase by ICR spectroscopy, J. Phys. Chem., 1980, 84, 2503. [all data]


Notes

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