Hydrogen cyanide

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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.

Quantity Value Units Method Reference Comment
Δfgas135.14kJ/molReviewChase, 1998Data last reviewed in December, 1969
Quantity Value Units Method Reference Comment
gas,1 bar201.82J/mol*KReviewChase, 1998Data last reviewed in December, 1969

Gas Phase Heat Capacity (Shomate Equation)

Cp° = 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
    Cp = 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.

Temperature (K) 298. to 1200.1200. to 6000.
A 32.6937352.36527
B 22.592055.563298
C -4.369142-0.953224
D -0.4076970.056711
E -0.282399-7.564086
F 123.4811103.8523
G 233.2597244.8448
H 135.1432135.1432
ReferenceChase, 1998Chase, 1998
Comment Data last reviewed in December, 1969 Data last reviewed in December, 1969

Phase change data

Go To: Top, Gas phase 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 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

Quantity Value Units Method Reference Comment
Tboil299.0 ± 0.5KAVGN/AAverage of 15 values; Individual data points
Quantity Value Units Method Reference Comment
Tfus260. ± 1.KAVGN/AAverage of 13 out of 14 values; Individual data points
Quantity Value Units Method Reference Comment
Ttriple259.86KN/AGiauque and Ruehrwein, 1939Crystal phase 1 phase; Uncertainty assigned by TRC = 0.02 K; TRC

Enthalpy of vaporization

ΔvapH (kJ/mol) Temperature (K) Method Reference Comment
25.217298.85N/AGiauque and Ruehrwein, 1939, 2P = 101.325 kPa.; DH
28.1274.AStephenson and Malanowski, 1987Based on data from 259. to 299. K.; AC
27.8313.AStephenson and Malanowski, 1987Based on data from 298. to 457. K.; AC
28.1272.N/AIwasaki and Date, 1975Based on data from 257. to 315. K.; AC
28.0277.N/ALewis and Schutz, 1934Based on data from 259. to 294. K.; AC
27.8282.N/APerry and Porter, 1926Based on data from 265. to 300. K.; AC
28.1272.N/ASinozaki, Hara, et al., 1926Based on data from 257. to 319. K.; AC
27.2303.MMSinozaki, Hara, et al., 1926Based on data from 256. to 319. K.; AC

Entropy of vaporization

ΔvapS (J/mol*K) Temperature (K) Reference Comment
84.38298.85Giauque and Ruehrwein, 1939, 2P; DH

Antoine Equation Parameters

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

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Temperature (K) A B C Reference Comment
256.73 to 319.384.674171340.791-11.592Sinozaki, Hara, et al., 1926Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

ΔsubH (kJ/mol) Temperature (K) Method Reference Comment
35.6248.N/AStephenson and Malanowski, 1987Based on data from 236. to 259. K.; AC
37.6228.AStull, 1947Based on data from 202. to 254. K.; AC

Enthalpy of fusion

ΔfusH (kJ/mol) Temperature (K) Reference Comment
8.406259.90Giauque and Ruehrwein, 1939, 2DH

Entropy of fusion

ΔfusS (J/mol*K) Temperature (K) Reference Comment
32.34259.90Giauque and Ruehrwein, 1939, 2DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change 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
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to CHN+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)13.60 ± 0.01eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)712.9kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity681.6kJ/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Method Reference Comment
0.00156N/AArd, Garrett, et al., 2009B
>1.00171EIAETsuda, Yokohata, et al., 1971From CH3CN; G3MP2B3 calculations indicate that the anion is unbound by ca. 1 eV. Possibly C2H3- instead.; B

Ionization energy determinations

IE (eV) Method Reference Comment
13.71EILageot, 1972LLK
13.59 ± 0.01PIDibeler and Liston, 1968RDSH
13.60 ± 0.01PEBaker and Turner, 1968RDSH
13.73 ± 0.09EIVarsel, Morrell, et al., 1960RDSH
13.7 ± 0.1EIKusch, Hustrulid, et al., 1937RDSH
13.61PEKreile, Schweig, et al., 1982Vertical value; LBLHLM
13.607 ± 0.002PEFridh and Asbrink, 1975Vertical value; LLK
13.60PEPotts and Williams, 1974Vertical value; LLK
13.61 ± 0.01PEFrost, Lee, et al., 1973Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C+23.8 ± 0.5?EIKusch, Hustrulid, et al., 1937RDSH
CH+21.8 ± 0.5NEIKusch, Hustrulid, et al., 1937RDSH
CN+19.43 ± 0.01HPIBerkowitz, Chupka, et al., 1969RDSH
CN+19.40 ± 0.02HPIDibeler and Liston, 1968RDSH
CN+20.1 ± 0.2HEIKusch, Hustrulid, et al., 1937RDSH
H+15.18 ± 0.02CN-PIBerkowitz, Chupka, et al., 1969RDSH
H+19.00 ± 0.01CNPIBerkowitz, Chupka, et al., 1969RDSH
NH+24.9 ± 0.5CEIKusch, Hustrulid, et al., 1937RDSH
N+25.6 ± 0.5CHEIKusch, Hustrulid, et al., 1937RDSH

De-protonation reactions

CN- + Hydrogen cation = Hydrogen cyanide

By formula: CN- + H+ = CHN

Quantity Value Units Method Reference Comment
Δr1464. ± 4.2kJ/molCIDTAkin and Ervin, 2006gas phase; B
Δr1466.5 ± 0.71kJ/molD-EABradforth, Kim, et al., 1993gas phase; B
Δr1469. ± 8.8kJ/molG+TSBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Δr1433. ± 4.6kJ/molH-TSAkin and Ervin, 2006gas phase; B
Δr1435.8 ± 1.1kJ/molH-TSBradforth, Kim, et al., 1993gas phase; B
Δr1438. ± 8.4kJ/molIMREBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B

References

Go To: Top, Gas phase thermochemistry data, Phase change 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.

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. [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, 2626-2633. [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]

Iwasaki and Date, 1975
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]

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]

Ard, Garrett, et al., 2009
Ard, S.; Garrett, W.R.; Compton, R.N.; Adamowicz, L.; Stepanian, S.G., Rotational states of dipole-bound anions of hydrogen cyanide., Chem. Phys. Lett., 2009, 473, 4-6, 223, https://doi.org/10.1016/j.cplett.2009.04.007 . [all data]

Tsuda, Yokohata, et al., 1971
Tsuda, S.; Yokohata, A.; Umaba, T., Measurement of negative ions formed by electron impact. VIII. Ionization efficiency curves of negative ions from methyl and ethyl cyanides, Bull. Chem. Soc. Jpn., 1971, 44, 1486. [all data]

Lageot, 1972
Lageot, C., Etude des etats excites de l'ion HCN+, J. Chim. Phys. Phys.-Chim. Biol., 1972, 68, 214. [all data]

Dibeler and Liston, 1968
Dibeler, V.H.; Liston, S.K., Mass-spectrometric study of photoionization. IX. Hydrogen cyanide and acetonitrile, J. Chem. Phys., 1968, 48, 4765. [all data]

Baker and Turner, 1968
Baker, C.; Turner, D.W., High resolution molecular photoelectron spectroscopy. III.Acetylenes and azaacetylenes, Proc. Roy. Soc. (London), 1968, A308, 19. [all data]

Varsel, Morrell, et al., 1960
Varsel, C.J.; Morrell, F.A.; Resnik, F.E.; Powell, W.A., Qualitative and quantitative analysis of organic compounds. Use of low-voltage mass spectrometry, Anal. Chem., 1960, 32, 182. [all data]

Kusch, Hustrulid, et al., 1937
Kusch, P.; Hustrulid, A.; Tate, J.T., The dissociation of HCN, C2H2, C2N2 and C2H4 by electron impact, Phys. Rev., 1937, 52, 843. [all data]

Kreile, Schweig, et al., 1982
Kreile, J.; Schweig, A.; Thiel, W., Experimental and theoretical investigation of the photoionization of hydrogen cyanide, Chem. Phys. Lett., 1982, 87, 473. [all data]

Fridh and Asbrink, 1975
Fridh, C.; Asbrink, L., Photoelectron electron impact spectrum of HCN, J. Electron Spectrosc. Relat. Phenom., 1975, 7, 119. [all data]

Potts and Williams, 1974
Potts, A.W.; Williams, T.A., The observation of "forbidden" transitions in He II photoelectron spectra, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 3. [all data]

Frost, Lee, et al., 1973
Frost, D.C.; Lee, S.T.; McDowell, C.A., The photoelectron spectrum of HCP and comments on the first photoelectron band of HCN, Chem. Phys. Lett., 1973, 23, 472. [all data]

Berkowitz, Chupka, et al., 1969
Berkowitz, J.; Chupka, W.A.; Walter, T.A., Photoionization of HCN: the electron affinity and heat of formation of CN, J. Chem. Phys., 1969, 50, 1497. [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]

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]


Notes

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