Nitrous acid

• Formula: HNO₂
• Molecular weight: 47.0134
• IUPAC Standard InChI: InChI=1S/HNO2/c2-1-3/h(H,2,3) Copy

  
• IUPAC Standard InChIKey: IOVCWXUNBOPUCH-UHFFFAOYSA-N Copy
• CAS Registry Number: 7782-77-6
• 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: HNO2; Kyselina dusite; Nitrosyl hydroxide; Nitrous acid, trans; HONO
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Ion clustering data
  • References
  • Notes
• Other data available:
  • Henry's Law data
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

Gas phase thermochemistry data

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

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering 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

 +  =

By formula: NO₂^- + H⁺ = HNO₂

 +  = ( • )

By formula: NO₂^- + HNO₂ = (NO₂^- • HNO₂)

 +  =  + 

By formula: C₈H₁₁N + HNO₂ = C₈H₁₀N₂O + H₂O

 +  =  + 

By formula: C₁₂H₁₁N + HNO₂ = H₂O + C₁₂H₁₀N₂O

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Ion clustering 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
LL - Sharon G. Lias and Joel F. Liebman

Ionization energy determinations

De-protonation reactions

 +  =

By formula: NO₂^- + H⁺ = HNO₂

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Reaction 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: John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

 +  = ( • )

By formula: NO₂^- + HNO₂ = (NO₂^- • HNO₂)

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Ervin, Ho, et al., 1988
Ervin, K.M.; Ho, J.; Lineberger, W.C., Ultraviolet Photoelectron Spectrum of NO₂^-, J. Phys. Chem., 1988, 92, 19, 5405, https://doi.org/10.1021/j100330a017 . [all data]

Lee, Keesee, et al., 1980
Lee, N.; Keesee, R.G.; Castleman, A.W., Jr., The properties of clusters in the gas phase. IV. Complexes of H₂O and HNO_x clustering on NO_x-, J. Chem. Phys., 1980, 72, 1089. [all data]

Swientoslawski, 1910
Swientoslawski, W., Thermochemische Untersuchungen der organischen Verbindungen. Dritte Mitteilung. Stickstoffhaltige Verbindungen., Z. Phys. Chem., 1910, 72, 49-83. [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys. Chem. Ref. Data, Suppl. 1, 1988, 17, 1-861. [all data]

Notes

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

• Symbols used in this document:
  

  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  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.