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
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Other data available:
- Condensed phase thermochemistry data
- Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 92
- Henry's Law data
- 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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Data at NIST subscription sites:

NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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Gas phase thermochemistry data

Go To: Top, Phase change data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, Gas Chromatography, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	32.299	kcal/mol	Review	Chase, 1998	Data last reviewed in December, 1969
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	48.236	cal/mol*K	Review	Chase, 1998	Data last reviewed in December, 1969

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 (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.

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View table.

Temperature (K)	298. to 1200.	1200. to 6000.
A	7.813990	12.51560
B	5.399630	1.329660
C	-1.044250	-0.227826
D	-0.097442	0.013554
E	-0.067495	-1.807860
F	29.51269	24.82130
G	55.75041	58.51931
H	32.30000	32.30000
Reference	Chase, 1998	Chase, 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, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, Gas Chromatography, References, Notes

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
T_boil	299.0 ± 0.5	K	AVG	N/A	Average of 15 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_fus	260. ± 1.	K	AVG	N/A	Average of 13 out of 14 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
T_triple	259.86	K	N/A	Giauque and Ruehrwein, 1939	Crystal phase 1 phase; Uncertainty assigned by TRC = 0.02 K; TRC

Enthalpy of vaporization

Δ_vapH (kcal/mol)	Temperature (K)	Method	Reference	Comment
6.0270	298.85	N/A	Giauque and Ruehrwein, 1939, 2	P = 101.325 kPa.; DH
6.72	274.	A	Stephenson and Malanowski, 1987	Based on data from 259. to 299. K.; AC
6.64	313.	A	Stephenson and Malanowski, 1987	Based on data from 298. to 457. K.; AC
6.72	272.	N/A	Iwasaki and Date, 1975	Based on data from 257. to 315. K.; AC
6.69	277.	N/A	Lewis and Schutz, 1934	Based on data from 259. to 294. K.; AC
6.64	282.	N/A	Perry and Porter, 1926	Based on data from 265. to 300. K.; AC
6.72	272.	N/A	Sinozaki, Hara, et al., 1926	Based on data from 257. to 319. K.; AC
6.50	303.	MM	Sinozaki, Hara, et al., 1926	Based on data from 256. to 319. K.; AC

Entropy of vaporization

Δ_vapS (cal/mol*K)	Temperature (K)	Reference	Comment
20.17	298.85	Giauque and Ruehrwein, 1939, 2	P; DH

Antoine Equation Parameters

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

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Temperature (K)	A	B	C	Reference	Comment
256.73 to 319.38	4.66846	1340.791	-11.592	Sinozaki, Hara, et al., 1926	Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

Δ_subH (kcal/mol)	Temperature (K)	Method	Reference	Comment
8.51	248.	N/A	Stephenson and Malanowski, 1987	Based on data from 236. to 259. K.; AC
8.99	228.	A	Stull, 1947	Based on data from 202. to 254. K.; AC

Enthalpy of fusion

Δ_fusH (kcal/mol)	Temperature (K)	Reference	Comment
2.009	259.90	Giauque and Ruehrwein, 1939, 2	DH

Entropy of fusion

Δ_fusS (cal/mol*K)	Temperature (K)	Reference	Comment
7.729	259.90	Giauque and Ruehrwein, 1939, 2	DH

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, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, Gas Chromatography, References, Notes

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)	170.4	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	162.9	kcal/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^- + = Hydrogen cyanide

By formula: CN^- + H⁺ = CHN

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	349.8 ± 1.0	kcal/mol	CIDT	Akin and Ervin, 2006	gas phase; B
Δ_rH°	350.50 ± 0.17	kcal/mol	D-EA	Bradforth, Kim, et al., 1993	gas phase; B
Δ_rH°	351.1 ± 2.1	kcal/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
Δ_rG°	342.5 ± 1.1	kcal/mol	H-TS	Akin and Ervin, 2006	gas phase; B
Δ_rG°	343.17 ± 0.27	kcal/mol	H-TS	Bradforth, Kim, et al., 1993	gas phase; B
Δ_rG°	343.8 ± 2.0	kcal/mol	IMRE	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, IR Spectrum, Vibrational and/or electronic energy levels, Gas Chromatography, References, Notes

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. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

+ Hydrogen cyanide = ( • )

By formula: Br^- + CHN = (Br^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.4 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Δ_rH°	16.0 ± 2.0	kcal/mol	Est	Larson and McMahon, 1984	gas phase; Extrapolated from other halide data; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.8	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	13.5 ± 1.6	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • Hydrogen cyanide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.3 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.7	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 2 Hydrogen cyanide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.9	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.30	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 3 Hydrogen cyanide ) + = ( • 4)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.4 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.1	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.80	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 4 Hydrogen cyanide ) + = ( • 5)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.1 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.5	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.60	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

+ Hydrogen cyanide = ( • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	22.0	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.	cal/mol*K	N/A	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M
Δ_rS°	21.4	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	15.6 ± 1.6	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy of 22.0 eu assumed.; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
11.8	473.	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M

( • Hydrogen cyanide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.8	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.	cal/mol*K	N/A	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M
Δ_rS°	23.6	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	10.70	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.6	350.	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M

CH₂N⁺ + Hydrogen cyanide = (CH₂N⁺ • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	26.1	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; Δ_rH, Δ_rS too small compared with other nitrile dimers; M
Δ_rH°	30.0	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.0	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; Δ_rH, Δ_rS too small compared with other nitrile dimers; M
Δ_rS°	32.	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

(CH₂N⁺ • Hydrogen cyanide ) + = (CH₂N⁺ • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.8	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

(CH₂N⁺ • 2 Hydrogen cyanide ) + = (CH₂N⁺ • 3)

By formula: (CH₂N⁺ • 2CHN) + CHN = (CH₂N⁺ • 3CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.8	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

(CH₂N⁺ • 3 Hydrogen cyanide ) + = (CH₂N⁺ • 4)

By formula: (CH₂N⁺ • 3CHN) + CHN = (CH₂N⁺ • 4CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.2	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.0	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

(CH₂N⁺ • Hydrogen cyanide • ) + = (CH₂N⁺ • 2 • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n, Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.	cal/mol*K	N/A	Meot-Ner (Mautner) and Speller, 1989	gas phase; n, Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	8.4	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n, Entropy change calculated or estimated; M

(CH₂N⁺ • ) + Hydrogen cyanide = (CH₂N⁺ • • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	18.8	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.4	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

(CH₂N⁺ • 2) + Hydrogen cyanide = (CH₂N⁺ • • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.9	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.1	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

+ Hydrogen cyanide = ( • )

By formula: CH₃O⁺ + CHN = (CH₃O⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	20.6	kcal/mol	FA	Tanaka, Mackay, et al., 1978	gas phase; switching reaction(H2COH+)H2CO; Fehsenfeld, Dotan, et al., 1978, Cunningham, Payzant, et al., 1972; M

CH₄NO⁺ + Hydrogen cyanide = (CH₄NO⁺ • )

By formula: CH₄NO⁺ + CHN = (CH₄NO⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.3	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.5	427.	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

CH₅O⁺ + Hydrogen cyanide = (CH₅O⁺ • )

By formula: CH₅O⁺ + CHN = (CH₅O⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	25.7	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.1	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

CH₆N⁺ + Hydrogen cyanide = (CH₆N⁺ • )

By formula: CH₆N⁺ + CHN = (CH₆N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20.8	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.9	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

CN^- + Hydrogen cyanide = (CN^- • )

By formula: CN^- + CHN = (CN^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.7 ± 3.5	kcal/mol	IMRE	Larson and McMahon, 1987	gas phase; B,M
Δ_rH°	20.0 ± 2.0	kcal/mol	Est	Larson and McMahon, 1984	gas phase; B
Δ_rH°	20.7	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rH°	20.7	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.6	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	20.6	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Δ_rS°	20.6	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Δ_rS°	26.9	cal/mol*K	N/A	Larson and McMahon, 1987	gas phase; switching reaction,Thermochemical ladder(H2O), Entropy change calculated or estimated; Payzant, Yamdagni, et al., 1971; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	14.5 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988	gas phase; B
Δ_rG°	13.7 ± 2.3	kcal/mol	IMRE	Larson and McMahon, 1987	gas phase; B,M
Δ_rG°	14.5 ± 1.6	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • Hydrogen cyanide ) + = (CN^- • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.4	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rH°	16.4	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.8	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	21.8	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Δ_rS°	21.8	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.90	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • 2 Hydrogen cyanide ) + = (CN^- • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rH°	12.6	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	21.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Δ_rS°	21.2	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.30	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • 3 Hydrogen cyanide ) + = (CN^- • 4)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.9	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rH°	10.9	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.8	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	24.8	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Δ_rS°	24.8	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • 4 Hydrogen cyanide ) + = (CN^- • 5)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Δ_rH°	9.8	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.2	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	20.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.80	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • 5 Hydrogen cyanide ) + = (CN^- • 6)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.5 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.4	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.40	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

(CN^- • 6 Hydrogen cyanide ) + = (CN^- • 7)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.6 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	N/A	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.60	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
3.0	238.	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M

(CN^- • Hydrogen cyanide • ) + = (CN^- • 2 • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.2	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.8	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

(CN^- • Hydrogen cyanide • 2) + = (CN^- • 2 • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
7.4	262.	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

(CN^- • 2 Hydrogen cyanide • ) + = (CN^- • 3 • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.3	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
7.1	262.	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

(CN^- • 3) + Hydrogen cyanide = (CN^- • • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.1	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
7.9	262.	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

+ Hydrogen cyanide = ( • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	22.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.5	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M

( • Hydrogen cyanide ) + = ( • 2)

By formula: (C₂H₃O₂^- • CHN) + CHN = (C₂H₃O₂^- • 2CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.6 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	10.60	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 2 Hydrogen cyanide ) + = ( • 3)

By formula: (C₂H₃O₂^- • 2CHN) + CHN = (C₂H₃O₂^- • 3CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.6	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.20	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 3 Hydrogen cyanide ) + = ( • 4)

By formula: (C₂H₃O₂^- • 3CHN) + CHN = (C₂H₃O₂^- • 4CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.0 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	27.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.90	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 4 Hydrogen cyanide ) + = ( • 5)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	N/A	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.40	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.5	213.	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M

C₂H₄N⁺ + Hydrogen cyanide = (C₂H₄N⁺ • )

By formula: C₂H₄N⁺ + CHN = (C₂H₄N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	22.1	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; CD3CNH+; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.1	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; CD3CNH+; M

C₂H₅O⁺ + Hydrogen cyanide = (C₂H₅O⁺ • )

By formula: C₂H₅O⁺ + CHN = (C₂H₅O⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	23.0	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₃H₂N⁺ + Hydrogen cyanide = (C₃H₂N⁺ • )

By formula: C₃H₂N⁺ + CHN = (C₃H₂N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	23.8	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.6	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

+ Hydrogen cyanide = ( • )

By formula: C₃H₃N₂^- + CHN = (C₃H₃N₂^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	23.9	kcal/mol	PHPMS	Meot-Ner (Mautner), 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.9	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1988	gas phase; M

C₃H₇⁺ + Hydrogen cyanide = (C₃H₇⁺ • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	39.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Sieck, 1991	gas phase; condensation; M
Δ_rH°	30.8	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; forms i-C3H7NCH+; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	45.2	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Sieck, 1991	gas phase; condensation; M
Δ_rS°	32.	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; forms i-C3H7NCH+; M

C₃H₇O⁺ + Hydrogen cyanide = (C₃H₇O⁺ • )

By formula: C₃H₇O⁺ + CHN = (C₃H₇O⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20.4	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.6	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₃H₁₀N⁺ + Hydrogen cyanide = (C₃H₁₀N⁺ • )

By formula: C₃H₁₀N⁺ + CHN = (C₃H₁₀N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.8	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.0	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₄H₈N⁺ + Hydrogen cyanide = (C₄H₈N⁺ • )

By formula: C₄H₈N⁺ + CHN = (C₄H₈N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20.1	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.5	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₄H₉⁺ + Hydrogen cyanide = (C₄H₉⁺ • )

By formula: C₄H₉⁺ + CHN = (C₄H₉⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.3	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; may form t-C4H9NCH+; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; may form t-C4H9NCH+; M

C₄H₉O₂⁺ + Hydrogen cyanide = (C₄H₉O₂⁺ • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.0	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.	cal/mol*K	N/A	Speller and Meot-Ner (Mautner), 1985	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
7.9	455.	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; Entropy change calculated or estimated; M

C₄H₁₀NO⁺ + Hydrogen cyanide = (C₄H₁₀NO⁺ • )

By formula: C₄H₁₀NO⁺ + CHN = (C₄H₁₀NO⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.8	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.8	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₇H₁₁O⁺ + Hydrogen cyanide = (C₇H₁₁O⁺ • )

By formula: C₇H₁₁O⁺ + CHN = (C₇H₁₁O⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.6	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.2	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

C₉H₂₂N⁺ + Hydrogen cyanide = (C₉H₂₂N⁺ • )

By formula: C₉H₂₂N⁺ + CHN = (C₉H₂₂N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.8	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	29.0	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

+ Hydrogen cyanide = ( • )

By formula: Cl^- + CHN = (Cl^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.8 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988	gas phase; B,B,M
Δ_rH°	21.0 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1984, 2	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.9	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Δ_rS°	23.7	cal/mol*K	N/A	Larson and McMahon, 1984, 3	gas phase; switching reaction(Cl-)t-C4H9OH, Entropy change calculated or estimated; French, Ikuta, et al., 1982; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	16.2 ± 1.6	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B
Δ_rG°	16.1 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988	gas phase; B
Δ_rG°	13.9 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1984, 2	gas phase; B,M

( • Hydrogen cyanide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.9 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.7	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	11.10	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 2 Hydrogen cyanide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.6 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.4	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.20	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 3 Hydrogen cyanide ) + = ( • 4)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.4	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.20	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 4 Hydrogen cyanide ) + = ( • 5)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.3	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 5 Hydrogen cyanide ) + = ( • 6)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.7 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.3	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 6 Hydrogen cyanide ) + = ( • 7)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.9 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.1	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.00	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 7 Hydrogen cyanide ) + = ( • 8)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	27.4	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.0 ± 2.2	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 8 Hydrogen cyanide ) + = ( • 9)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.5 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	N/A	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.10	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy estimated; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
3.2	171.	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; Entropy change calculated or estimated; M

+ Hydrogen cyanide = ( • )

By formula: F^- + CHN = (F^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	39.5 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1983	gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.2	cal/mol*K	N/A	Larson and McMahon, 1983	gas phase; switching reaction(F-)H2O, Entropy change calculated or estimated; Arshadi, Yamdagni, et al., 1970; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	32.9 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1983	gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M

HS^- + Hydrogen cyanide = (HS^- • )

By formula: HS^- + CHN = (HS^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.0 ± 1.0	kcal/mol	IMRE	Meot-ner, 1988	gas phase; See also H2S..CN-; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	15.0 ± 1.0	kcal/mol	IMRE	Meot-ner, 1988	gas phase; See also H2S..CN-; B

( • 2) + Hydrogen cyanide = ( • • 2)

By formula: (H₃O⁺ • 2H₂O) + CHN = (H₃O⁺ • CHN • 2H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.8	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	29.3	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M

+ Hydrogen cyanide = ( • )

By formula: H₄N⁺ + CHN = (H₄N⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.9	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Δ_rH°	20.5	kcal/mol	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.4	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Δ_rS°	20.2	cal/mol*K	PHPMS	Speller and Meot-Ner (Mautner), 1985	gas phase; M

( • Hydrogen cyanide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.4	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.4	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 2 Hydrogen cyanide ) + = ( • 3)

By formula: (H₄N⁺ • 2CHN) + CHN = (H₄N⁺ • 3CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.7	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.5	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 3 Hydrogen cyanide ) + = ( • 4)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.0	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.9	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 4 Hydrogen cyanide ) + = ( • 5)

By formula: (H₄N⁺ • 4CHN) + CHN = (H₄N⁺ • 5CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.9	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.9	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 5 Hydrogen cyanide ) + = ( • 6)

By formula: (H₄N⁺ • 5CHN) + CHN = (H₄N⁺ • 6CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.4	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.9	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • Hydrogen cyanide • ) + = ( • 2 • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.2	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.4	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • Hydrogen cyanide • 2) + = ( • 2 • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.2	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	N/A	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.9	315.	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated; M

( • 2 Hydrogen cyanide • ) + = ( • 3 • )

By formula: (H₄N⁺ • 2CHN • H₃N) + CHN = (H₄N⁺ • 3CHN • H₃N)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.8	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.1	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 3 Hydrogen cyanide • ) + = ( • 4 • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.6	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated, T = 392 in paper is error; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	N/A	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated, T = 392 in paper is error; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
2.7	292.	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated, T = 392 in paper is error; M

( • ) + Hydrogen cyanide = ( • • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.2	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.5	cal/mol*K	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; M

( • 2) + Hydrogen cyanide = ( • • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.4	kcal/mol	PHPMS	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.3	cal/mol*K	N/A	Deakyne, Knuth, et al., 1994	gas phase; Entropy change calculated or estimated; M

+ Hydrogen cyanide = ( • )

By formula: I^- + CHN = (I^- • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	10.4 ± 1.6	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • Hydrogen cyanide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.0	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.20	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 2 Hydrogen cyanide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.0	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.90	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 3 Hydrogen cyanide ) + = ( • 4)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.2 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.20	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 4 Hydrogen cyanide ) + = ( • 5)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.6 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.9	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.80	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 5 Hydrogen cyanide ) + = ( • 6)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.4 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.9	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 6 Hydrogen cyanide ) + = ( • 7)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.4 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.9	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

( • 7 Hydrogen cyanide ) + = ( • 8)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.8 ± 1.0	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	PHPMS	Meot-ner, Cybulski, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.50	kcal/mol	TDAs	Meot-ner, Cybulski, et al., 1988	gas phase; B

+ Hydrogen cyanide = ( • )

By formula: Li⁺ + CHN = (Li⁺ • CHN)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	36.4	kcal/mol	ICR	Woodin and Beauchamp, 1978	gas phase; switching reaction(Li+)H2O, Entropy change calculated or estimated; Dzidic and Kebarle, 1970 interpolated; M
Δ_rH°	36.	kcal/mol	ICR	Staley and Beauchamp, 1975	gas phase; switching reaction(Li+)H2O, from graph; Dzidic and Kebarle, 1970 extrapolated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	N/A	Woodin and Beauchamp, 1978	gas phase; switching reaction(Li+)H2O, Entropy change calculated or estimated; Dzidic and Kebarle, 1970 interpolated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	28.	kcal/mol	ICR	Woodin and Beauchamp, 1978	gas phase; switching reaction(Li+)H2O, Entropy change calculated or estimated; Dzidic and Kebarle, 1970 interpolated; M

IR Spectrum

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, Vibrational and/or electronic energy levels, Gas Chromatography, References, Notes

Data compiled by: Coblentz Society, Inc.

Spectrum

A digitized version of this spectrum is not currently available.

Additional Data

View scan of original (hardcopy) spectrum.

Owner	COBLENTZ SOCIETY Collection (C) 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.
Source reference	COBLENTZ NO. 10480
Date	Not specified, most likely prior to 1982
Instrument	Not specified, most likely a prism, grating, or hybrid spectrometer.
Data processing	(NO SPECTRUM, ONLY SCANNED IMAGE IS AVAILABLE)

This IR spectrum is from the Coblentz Society's evaluated infrared reference spectra collection.

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Gas Chromatography, References, Notes

Data compiled by: Takehiko Shimanouchi

Symmetry: C_∞ν Symmetry Number σ = 1

Sym.	No	Approximate	Selected Freq.		Infrared		Raman

Species		type of mode	Value	Rating	Value	Phase	Value	Phase

σ⁺	1	CH str	3311	A	3311.47 S	gas	3313 W	liq.
π	2	Bend	712	A	711.98 VS	gas	712 W	liq.
σ⁺	3	CN str	2097	A	2096.85 W	gas	2089 S	liq.

Source: Shimanouchi, 1972

Notes

Very strong

Strong

Weak

0~1 cm^-1 uncertainty

Gas Chromatography

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, References, Notes

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

Kovats' RI, non-polar column, isothermal

View large format table.

Column type	Active phase	Temperature (C)	I	Reference	Comment
Capillary	CP Sil 5 CB	20.	319.9	Do and Raulin, 1992	25. m/0.15 mm/2. μm, H2
Capillary	PoraPLOT Q	160.	300.	Do and Raulin, 1989	10. m/0.32 mm/10. μm, H2

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

View large format table.

Column type	Active phase	I	Reference	Comment
Capillary	Polydimethyl siloxane	320.	Staples, 2006	Program: not specified

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, Gas Chromatography, Notes

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]

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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]

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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]

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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]

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]

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, 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]

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) 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]

Tanaka, Mackay, et al., 1978
Tanaka, K.; Mackay, G.I.; Bohme, D.K., Rate and Equilibrium Constant Measurements for Gas-Phase Proton-Transfer Reactions Involving H2O, H2S, HCN, and H2CO, Can. J. Chem., 1978, 56, 2, 193, https://doi.org/10.1139/v78-031 . [all data]

Fehsenfeld, Dotan, et al., 1978
Fehsenfeld, F.C.; Dotan, I.; Albritton, D.L.; Howard, C.J.; Ferguson, E.E., Stratospheric Positive Ion Chemistry of Formaldehyde and Methanol, J. Geophys. Res., 1978, 83, C3, 1333, https://doi.org/10.1029/JC083iC03p01333 . [all data]

Cunningham, Payzant, et al., 1972
Cunningham, A.J.; Payzant, J.D.; Kebarle, P., A Kinetic Study of the Proton Hydrate H+(H2O)n Equilibria in the Gas Phase, J. Am. Chem. Soc., 1972, 94, 22, 7627, https://doi.org/10.1021/ja00777a003 . [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]

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]

Meot-Ner (Mautner), 1988
Meot-Ner (Mautner), M., Models for Strong Interactions in Proteins and Enzymes. 2. Interactions of Ions with the Peptide Link and Imidazole, J. Am. Chem. Soc., 1988, 110, 10, 3075, https://doi.org/10.1021/ja00218a014 . [all data]

Meot-Ner (Mautner) and Sieck, 1991
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Notes

Symbols used in this document:

AE	Appearance energy
EA	Electron affinity
IE (evaluated)	Recommended ionization energy
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
T	Temperature
T_boil	Boiling point
T_fus	Fusion (melting) point
T_triple	Triple point temperature
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fusH	Enthalpy of fusion
Δ_fusS	Entropy of fusion
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions
Δ_rS°	Entropy of reaction at standard conditions
Δ_subH	Enthalpy of sublimation
Δ_vapH	Enthalpy of vaporization
Δ_vapS	Entropy of vaporization

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.
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Hydrogen cyanide

Data at NIST subscription sites:

Gas phase thermochemistry data

Gas Phase Heat Capacity (Shomate Equation)

Phase change data

Enthalpy of vaporization

Entropy of vaporization

Antoine Equation Parameters

Enthalpy of sublimation

Enthalpy of fusion

Entropy of fusion

Gas phase ion energetics data

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

Ion clustering data

Clustering reactions

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

Free energy of reaction

IR Spectrum

Spectrum

Additional Data

Vibrational and/or electronic energy levels

Symmetry: C∞ν Symmetry Number σ = 1

Notes

Gas Chromatography

Kovats' RI, non-polar column, isothermal

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

References

Notes

Symmetry: C_∞ν Symmetry Number σ = 1