Hydrogen cyanide

• Formula: CHN
• Molecular weight: 27.0253
• IUPAC Standard InChI: InChI=1S/CHN/c1-2/h1H Copy

  
• IUPAC Standard InChIKey: LELOWRISYMNNSU-UHFFFAOYSA-N Copy
• CAS Registry Number: 74-90-8
• Chemical structure:
  This structure is also available as a 2d Mol file
• Other names: Hydrocyanic acid; AC; Blausaeure (German); Carbon hydride nitride (CHN); Formic anammonide; Formonitrile; HCN; Prussic Acid; Cyclon; Acide cyanhydrique; Acido cianidrico; Aero Liquid HCN; Blausaeure; Blauwzuur; Cyaanwaterstof; Cyanwasserstoff; Cyclone B; Cyjanowodor; Evercyn; NA 1051; Prussic acid, unstabilized; Rcra waste number P063; UN 1051; Zaclondiscoids; Carbon hydride nitride; Zootic acid; Agent AC; Nitrilomethane
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data (reactions 1 to 50)
  • Henry's Law data
  • Vibrational and/or electronic energy levels
  • Gas Chromatography
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data: reactions 51 to 92
  • Gas phase ion energetics data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
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Gas phase thermochemistry 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.

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.

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View table.

Condensed phase thermochemistry 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 compiled by: Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

Phase change 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 compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
DH - Eugene S. Domalski and Elizabeth D. Hearing
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of vaporization

Entropy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

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Enthalpy of sublimation

Enthalpy of fusion

Entropy of fusion

Reaction thermochemistry 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 compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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.

Reactions 1 to 50

CN^- +  = (CN^- • )

By formula: CN^- + CHN = (CN^- • CHN)

 +  = ( • )

By formula: F^- + CHN = (F^- • CHN)

 +  = ( • )

By formula: Li⁺ + CHN = (Li⁺ • CHN)

 +  = ( • )

By formula: Cl^- + CHN = (Cl^- • CHN)

CN^- +  =

By formula: CN^- + H⁺ = CHN

 +  = ( • )

By formula: CHO₂^- + CHN = (CHO₂^- • CHN)

Free energy of reaction

( • ) +  = ( • 2)

By formula: (CHO₂^- • CHN) + CHN = (CHO₂^- • 2CHN)

Free energy of reaction

( • 3 • ) +  = ( • 4 • )

By formula: (H₄N⁺ • 3CHN • H₃N) + CHN = (H₄N⁺ • 4CHN • H₃N)

Free energy of reaction

( • 8) +  = ( • 9)

By formula: (Cl^- • 8CHN) + CHN = (Cl^- • 9CHN)

Free energy of reaction

( • 4) +  = ( • 5)

By formula: (C₂H₃O₂^- • 4CHN) + CHN = (C₂H₃O₂^- • 5CHN)

Free energy of reaction

(CN^- • 6) +  = (CN^- • 7)

By formula: (CN^- • 6CHN) + CHN = (CN^- • 7CHN)

Free energy of reaction

(CN^- • 2) +  = (CN^- • 3)

By formula: (CN^- • 2CHN) + CHN = (CN^- • 3CHN)

(CN^- • 3) +  = (CN^- • 4)

By formula: (CN^- • 3CHN) + CHN = (CN^- • 4CHN)

(CN^- • ) +  = (CN^- • 2)

By formula: (CN^- • CHN) + CHN = (CN^- • 2CHN)

CH₂N⁺ +  = (CH₂N⁺ • )

By formula: CH₂N⁺ + CHN = (CH₂N⁺ • CHN)

(CN^- •  • 2) +  = (CN^- • 2 • 2)

By formula: (CN^- • H₂O • 2CHN) + H₂O = (CN^- • 2H₂O • 2CHN)

Free energy of reaction

(CN^- • 3) +  = (CN^- •  • 3)

By formula: (CN^- • 3CHN) + H₂O = (CN^- • H₂O • 3CHN)

Free energy of reaction

(CH₂N⁺ •  • ) +  = (CH₂N⁺ • 2 • )

By formula: (CH₂N⁺ • CHN • H₂O) + CHN = (CH₂N⁺ • 2CHN • H₂O)

( •  • 2) +  = ( • 2 • 2)

By formula: (H₄N⁺ • H₃N • 2CHN) + H₃N = (H₄N⁺ • 2H₃N • 2CHN)

Free energy of reaction

( •  • 2) +  = ( • 2 • 2)

By formula: (H₄N⁺ • CHN • 2H₃N) + CHN = (H₄N⁺ • 2CHN • 2H₃N)

Free energy of reaction

(CN^- • 4) +  = (CN^- • 5)

By formula: (CN^- • 4CHN) + CHN = (CN^- • 5CHN)

( • ) +  = ( •  • )

By formula: (H₄N⁺ • CHN) + H₃N = (H₄N⁺ • H₃N • CHN)

Free energy of reaction

 +  = ( • )

By formula: Br^- + CHN = (Br^- • CHN)

C₄H₉O₂⁺ +  = (C₄H₉O₂⁺ • )

By formula: C₄H₉O₂⁺ + CHN = (C₄H₉O₂⁺ • CHN)

Free energy of reaction

C₃H₇⁺ +  = (C₃H₇⁺ • )

By formula: C₃H₇⁺ + CHN = (C₃H₇⁺ • CHN)

HS^- +  = (HS^- • )

By formula: HS^- + CHN = (HS^- • CHN)

 +  = ( • )

By formula: H₄N⁺ + CHN = (H₄N⁺ • CHN)

(CN^- •  • ) +  = (CN^- • 2 • )

By formula: (CN^- • H₂O • CHN) + H₂O = (CN^- • 2H₂O • CHN)

(CN^- • 2) +  = (CN^- •  • 2)

By formula: (CN^- • 2CHN) + H₂O = (CN^- • H₂O • 2CHN)

(CN^- • ) +  = (CN^- •  • )

By formula: (CN^- • CHN) + H₂O = (CN^- • H₂O • CHN)

( • 7) +  = ( • 8)

By formula: (Cl^- • 7CHN) + CHN = (Cl^- • 8CHN)

(CN^- •  • 2) +  = (CN^- • 2 • 2)

By formula: (CN^- • CHN • 2H₂O) + CHN = (CN^- • 2CHN • 2H₂O)

Free energy of reaction

(CN^- • 2 • ) +  = (CN^- • 3 • )

By formula: (CN^- • 2CHN • H₂O) + CHN = (CN^- • 3CHN • H₂O)

Free energy of reaction

( • 2) +  = ( • 3)

By formula: (Cl^- • 2CHN) + CHN = (Cl^- • 3CHN)

( • 3) +  = ( • 4)

By formula: (Cl^- • 3CHN) + CHN = (Cl^- • 4CHN)

( • ) +  = ( • 2)

By formula: (Cl^- • CHN) + CHN = (Cl^- • 2CHN)

( • 2) +  = ( • 3)

By formula: (I^- • 2CHN) + CHN = (I^- • 3CHN)

( • 2) +  = ( • 3)

By formula: (Br^- • 2CHN) + CHN = (Br^- • 3CHN)

( • 3) +  = ( • 4)

By formula: (Br^- • 3CHN) + CHN = (Br^- • 4CHN)

( • 4) +  = ( • 5)

By formula: (Cl^- • 4CHN) + CHN = (Cl^- • 5CHN)

( • 5) +  = ( • 6)

By formula: (Cl^- • 5CHN) + CHN = (Cl^- • 6CHN)

( • 6) +  = ( • 7)

By formula: (Cl^- • 6CHN) + CHN = (Cl^- • 7CHN)

( • 3) +  = ( • 4)

By formula: (I^- • 3CHN) + CHN = (I^- • 4CHN)

( • 4) +  = ( • 5)

By formula: (I^- • 4CHN) + CHN = (I^- • 5CHN)

( • 5) +  = ( • 6)

By formula: (I^- • 5CHN) + CHN = (I^- • 6CHN)

( • 6) +  = ( • 7)

By formula: (I^- • 6CHN) + CHN = (I^- • 7CHN)

( • 7) +  = ( • 8)

By formula: (I^- • 7CHN) + CHN = (I^- • 8CHN)

( • ) +  = ( • 2)

By formula: (I^- • CHN) + CHN = (I^- • 2CHN)

( • 4) +  = ( • 5)

By formula: (Br^- • 4CHN) + CHN = (Br^- • 5CHN)

( • ) +  = ( • 2)

By formula: (Br^- • CHN) + CHN = (Br^- • 2CHN)

Henry's Law 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 compiled by: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

Vibrational and/or electronic energy levels

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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 compiled by: Takehiko Shimanouchi

Symmetry:   C_∞ν     Symmetry Number σ = 1

Source: Shimanouchi, 1972

Notes

Gas Chromatography

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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 compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Kovats' RI, non-polar column, isothermal

View large format table.

Normal alkane RI, non-polar column, custom temperature program

View large format table.

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Vibrational and/or electronic energy levels, Gas Chromatography, 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]

Giauque and Ruehrwein, 1939
Giauque, W.F.; Ruehrwein, R.A., The entropy of hydrogen cyanide. Heat capacity, heat of vaporization and vapor pressure. Hydrogen bond polymerization of the gas in chains of indefinite length, J. Am. Chem. Soc., 1939, 61, 2626-2633. [all data]

Giauque and Ruehrwein, 1939, 2
Giauque, W.F.; Ruehrwein, R.A., The Entropy of Hydrogen Cyanide. Heat Capacity, Heat of Vaporization and Vapor Pressure. Hydrogen Bond Polymerization of the Gas in Chains of Indefinite Length., J. Am. Chem. Soc., 1939, 61, 2626. [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

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Iwasaki, H.; Date, K., Koatsu Gasu, 1975, 12, 374. [all data]

Lewis and Schutz, 1934
Lewis, Gilbert N.; Schutz, Philip W., THE VAPOR PRESSURE OF LIQUID AND SOLID DEUTOCYANIC ACID, J. Am. Chem. Soc., 1934, 56, 4, 1002-1002, https://doi.org/10.1021/ja01319a514 . [all data]

Perry and Porter, 1926
Perry, J.H.; Porter, Frank, THE VAPOR PRESSURES OF SOLID AND LIQUID HYDROGEN CYANIDE ¹, J. Am. Chem. Soc., 1926, 48, 2, [299]-302, https://doi.org/10.1021/ja01413a001 . [all data]

Sinozaki, Hara, et al., 1926
Sinozaki, Heima; Hara, Ryozaburo; Mitsukuri, Shinroku, THE VAPOUR PRESSURES OF HYDROGEN CYANIDE, Bull. Chem. Soc. Jpn., 1926, 1, 4, 59-61, https://doi.org/10.1246/bcsj.1.59 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Larson and McMahon, 1987
Larson, J.W.; McMahon, T.B., Hydrogen bonding in gas phase anions. The energetics of interaction between cyanide ion and bronsted acids, J. Am. Chem. Soc., 1987, 109, 6230. [all data]

Larson and McMahon, 1984
Larson, J.W.; McMahon, T.B., Gas phase bihalide and pseudohalide ions. An ICR determination of hydrogen bond energies in XHY- species (X,Y = F, Cl, Br, CN), Inorg. Chem., 1984, 23, 2029. [all data]

Meot-Ner (Mautner) and Speller, 1989
Meot-Ner (Mautner), M.; Speller, C.V., Multicomponent Cluster Ions.3. Comparative Stabilities of Cationic and Anionic Hydrogen Bonded Networks. Mixed Clusters of Water and Hydrogen Cyanide, J. Phys. Chem., 1989, 93, 6580. [all data]

Meot-ner, 1988
Meot-ner, M., Ionic Hydrogen Bond and Ion Solvation. ₆. Interaction Energies of the Acetate Ion with Organic Molecules. Comparison of CH₃COO^- with Cl^-, CN^-, and SH^-, J. Am. Chem. Soc., 1988, 110, 12, 3854, https://doi.org/10.1021/ja00220a022 . [all data]

Meot-ner, Cybulski, et al., 1988
Meot-ner, M.; Cybulski, S.M.; Scheiner, S.; Liebman, J.F., Is CN^- Significantly Anisotropic? Comparison of CN^- vs. Cl^-: Clustering with HCN and Condensed Phase Thermochemistry, J. Phys. Chem., 1988, 92, 10, 2738, https://doi.org/10.1021/j100321a009 . [all data]

Payzant, Yamdagni, et al., 1971
Payzant, J.D.; Yamdagni, R.; Kebarle, P., Hydration of CN-, NO₂-, NO₃-, and HO- in the gas phase, Can. J. Chem., 1971, 49, 3308. [all data]

Larson and McMahon, 1983
Larson, J.W.; McMahon, T.B., Strong hydrogen bonding in gas-phase anions. An ion cyclotron resonance determination of fluoride binding energetics to bronsted acids from gas-phase fluoride exchange equilibria measurements, J. Am. Chem. Soc., 1983, 105, 2944. [all data]

Wenthold and Squires, 1995
Wenthold, P.G.; Squires, R.R., Bond dissociation energies of F2(-) and HF2(-). A gas-phase experimental and G2 theoretical study, J. Phys. Chem., 1995, 99, 7, 2002, https://doi.org/10.1021/j100007a034 . [all data]

Arshadi, Yamdagni, et al., 1970
Arshadi, M.; Yamdagni, R.; Kebarle, P., Hydration of Halide Negative Ions in the Gas Phase. II. Comparison of Hydration Energies for the Alkali Positive and Halide Negative Ions, J. Phys. Chem., 1970, 74, 7, 1475, https://doi.org/10.1021/j100702a014 . [all data]

Woodin and Beauchamp, 1978
Woodin, R.L.; Beauchamp, J.L., Bonding of Li+ to Lewis Bases in the Gas Phase. Reversals in Methyl Substituent Effects for Different Reference Acids, J. Am. Chem. Soc., 1978, 100, 2, 501, https://doi.org/10.1021/ja00470a024 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Larson and McMahon, 1984, 2
Larson, J.W.; McMahon, T.B., Hydrogen bonding in gas phase anions. An experimental investigation of the interaction between chloride ion and bronsted acids from ICR chloride exchange equilibria, J. Am. Chem. Soc., 1984, 106, 517. [all data]

Larson and McMahon, 1984, 3
Larson, J.W.; McMahon, T.B., Gas phase negative ion chemistry of alkylchloroformates, Can. J. Chem., 1984, 62, 675. [all data]

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French, M.A.; Ikuta, S.; Kebarle, P., Hydrogen bonding of O-H and C-H hydrogen donors to Cl^-. Results from mass spectrometric measurement of the ion-molecule equilibria RH + Cl^- = RHCl^-, Can. J. Chem., 1982, 60, 1907. [all data]

Akin and Ervin, 2006
Akin, F.A.; Ervin, K.M., Collision-induced dissociation of HS-(HCN): Unsymmetrical hydrogen bonding in a proton-bound dimer anion, J. Phys. Chem. A, 2006, 110, 4, 1342-1349, https://doi.org/10.1021/jp0540454 . [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]

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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]

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Deakyne, C.A.; Knuth, D.M.; Speller, C.V.; Meot-Ner (Mautner), M.; Sieck, L.W., Filling of Solvent Shells about Ions. Part 3. Isomeric Clusters of (HCN)n(NH3)mH+, J. Mol. Structure (Theochem), 1994, 307, 217, https://doi.org/10.1016/0166-1280(94)80130-4 . [all data]

Speller and Meot-Ner (Mautner), 1985
Speller, C.V.; Meot-Ner (Mautner), M., The Ionic Hydrogen Bond and Ion Solvation. 3. Bonds Involving Cyanides. Correlations with Proton Affinites, J. Phys. Chem., 1985, 81, 24, 5217, https://doi.org/10.1021/j100270a020 . [all data]

Meot-Ner (Mautner), 1978
Meot-Ner (Mautner), M., Solvation of the Proton by HCN and CH3CN. Condensation of HCN with Ions in the Gas Phase., J. Am. Chem. Soc., 1978, 100, 15, 4694, https://doi.org/10.1021/ja00483a012 . [all data]

Meot-Ner (Mautner) M. and Speller, 1989
Meot-Ner (Mautner) M.; Speller, C.V., Multicomponent Cluster Ions. 2. Comparative Stabilities of Cationic and Anionic Hydrogen Bonded Networks. Mixed Clusters of Water and Hydrogen Cyanide, J. Phys. Chem., 1989, 93, 9, 3663, https://doi.org/10.1021/j100346a058 . [all data]

Meot-Ner (Mautner) and Sieck, 1991
Meot-Ner (Mautner), M.; Sieck, L.W., Proton affinity ladders from variable-temperature equilibrium measurements. 1. A reevaluation of the upper proton affinity range, J. Am. Chem. Soc., 1991, 113, 12, 4448, https://doi.org/10.1021/ja00012a012 . [all data]

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Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume I, National Bureau of Standards, 1972, 1-160. [all data]

Do and Raulin, 1992
Do, L.; Raulin, F., Gas chromatography of Titan's atmosphere. III. Analysis of low-molecular-weight hydrocarbons and nitriles with a CP-Sil-5 CB WCOT capillary column, J. Chromatogr., 1992, 591, 1-2, 297-301, https://doi.org/10.1016/0021-9673(92)80247-R . [all data]

Do and Raulin, 1989
Do, L.; Raulin, F., Gas chromatography of Titan's atmosphere. I. Analysis of low-molecular-weight hydrocarbons and nitriles with a PoraPLOT Q porous polymer coated open-tubular capillary column, J. Chromatogr., 1989, 481, 45-54, https://doi.org/10.1016/S0021-9673(01)96751-2 . [all data]

Staples, 2006
Staples, E.J., Creating a compound library for chemical warfare agents for the ZNose, 2006, retrieved from http://www.estcal.com/TechPapers/Security/CWA-Libraries.pdf. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Vibrational and/or electronic energy levels, Gas Chromatography, References

• Symbols used in this document:
  

  Cp,liquid	Constant pressure heat capacity of liquid
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  S°liquid	Entropy of liquid at standard conditions
  T	Temperature
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation
  ΔvapH	Enthalpy of vaporization
  ΔvapS	Entropy of vaporization

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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