Hydrogen cyanide
- Formula: CHN
- Molecular weight: 27.0253
- IUPAC Standard InChI: InChI=1S/CHN/c1-2/h1H
- IUPAC Standard InChIKey: LELOWRISYMNNSU-UHFFFAOYSA-N
- 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
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- Information on this page:
- Other data available:
- Gas phase thermochemistry data
- Condensed phase thermochemistry data
- Phase change data
- Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 92
- Henry's Law data
- Ion clustering data
- IR Spectrum
- Mass spectrum (electron ionization)
- Vibrational and/or electronic energy levels
- Gas Chromatography
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Gas phase ion energetics data
Go To: Top, 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 ± 0.01 | eV | N/A | N/A | L |
| Quantity | Value | Units | Method | Reference | Comment |
| Proton affinity (review) | 712.9 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
| Quantity | Value | Units | Method | Reference | Comment |
| Gas basicity | 681.6 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Electron affinity determinations
| EA (eV) | Method | Reference | Comment |
|---|---|---|---|
| 0.00156 | N/A | Ard, Garrett, et al., 2009 | B |
| >1.00171 | EIAE | Tsuda, Yokohata, et al., 1971 | From 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 |
|---|---|---|---|
| 13.71 | EI | Lageot, 1972 | LLK |
| 13.59 ± 0.01 | PI | Dibeler and Liston, 1968 | RDSH |
| 13.60 ± 0.01 | PE | Baker and Turner, 1968 | RDSH |
| 13.73 ± 0.09 | EI | Varsel, Morrell, et al., 1960 | RDSH |
| 13.7 ± 0.1 | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
| 13.61 | PE | Kreile, Schweig, et al., 1982 | Vertical value; LBLHLM |
| 13.607 ± 0.002 | PE | Fridh and Asbrink, 1975 | Vertical value; LLK |
| 13.60 | PE | Potts and Williams, 1974 | Vertical value; LLK |
| 13.61 ± 0.01 | PE | Frost, Lee, et al., 1973 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| C+ | 23.8 ± 0.5 | ? | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
| CH+ | 21.8 ± 0.5 | N | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
| CN+ | 19.43 ± 0.01 | H | PI | Berkowitz, Chupka, et al., 1969 | RDSH |
| CN+ | 19.40 ± 0.02 | H | PI | Dibeler and Liston, 1968 | RDSH |
| CN+ | 20.1 ± 0.2 | H | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
| H+ | 15.18 ± 0.02 | CN- | PI | Berkowitz, Chupka, et al., 1969 | RDSH |
| H+ | 19.00 ± 0.01 | CN | PI | Berkowitz, Chupka, et al., 1969 | RDSH |
| NH+ | 24.9 ± 0.5 | C | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
| N+ | 25.6 ± 0.5 | CH | EI | Kusch, Hustrulid, et al., 1937 | RDSH |
De-protonation reactions
CN- + =
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1464. ± 4.2 | kJ/mol | CIDT | Akin and Ervin, 2006 | gas phase; B |
| ΔrH° | 1466.5 ± 0.71 | kJ/mol | D-EA | Bradforth, Kim, et al., 1993 | gas phase; B |
| ΔrH° | 1469. ± 8.8 | kJ/mol | G+TS | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1433. ± 4.6 | kJ/mol | H-TS | Akin and Ervin, 2006 | gas phase; B |
| ΔrG° | 1435.8 ± 1.1 | kJ/mol | H-TS | Bradforth, Kim, et al., 1993 | gas phase; B |
| ΔrG° | 1438. ± 8.4 | kJ/mol | IMRE | Bartmess, Scott, et al., 1979 | gas phase; value altered from reference due to change in acidity scale; 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]
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 ion energetics data, References
- Symbols used in this document:
AE Appearance energy EA Electron affinity 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
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