Isocyanic acid

• Formula: CHNO
• Molecular weight: 43.0247
• IUPAC Standard InChI: InChI=1S/CHNO/c2-1-3/h2H Copy

  
• IUPAC Standard InChIKey: OWIKHYCFFJSOEH-UHFFFAOYSA-N Copy
• CAS Registry Number: 75-13-8
• 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.
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Vibrational and/or electronic energy levels
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

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 by: John E. Bartmess

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

CNO^- +  =

By formula: CNO^- + H⁺ = CHNO

(CAS Reg. No. 1140500-24-8 • 4294967295) +  = CAS Reg. No. 1140500-24-8

By formula: (CAS Reg. No. 1140500-24-8 • 4294967295CHNO) + CHNO = CAS Reg. No. 1140500-24-8

(CAS Reg. No. 67131-48-0 • 4294967295) +  = CAS Reg. No. 67131-48-0

By formula: (CAS Reg. No. 67131-48-0 • 4294967295CHNO) + CHNO = CAS Reg. No. 67131-48-0

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 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

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

CNO^- +  =

By formula: CNO^- + H⁺ = CHNO

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.

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]

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]

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]

Notes

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization 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
• 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.