Cyanogen iodide

Formula: CIN
Molecular weight: 152.9219
IUPAC Standard InChI: InChI=1S/CIN/c2-1-3
IUPAC Standard InChIKey: WPBXOELOQKLBDF-UHFFFAOYSA-N
CAS Registry Number: 506-78-5
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other data available:
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 compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	225.94	kJ/mol	Review	Chase, 1998	Data last reviewed in June, 1969
Δ_fH°_gas	224.6 ± 4.3	kJ/mol	Cm	Lord and Woolf, 1954	Reanalyzed by Cox and Pilcher, 1970, Original value = 219. kJ/mol; Heat of hydrolysis; ALS
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	257.34	J/mol*K	Review	Chase, 1998	Data last reviewed in June, 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 (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.

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Temperature (K)	298. to 1200.	1200. to 6000.
A	49.26325	60.08266
B	7.560865	1.205993
C	3.675051	-0.234558
D	-2.880508	0.015758
E	-0.297113	-4.021343
F	209.8895	199.1258
G	312.8946	318.3991
H	225.9364	225.9364
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in June, 1969	Data last reviewed in June, 1969

Phase change data

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Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos

Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	40.0 ± 0.3	kJ/mol	V	Ketellaar and Kruyer, 1943	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_subH°	59.83 ± 0.42	kJ/mol	V	Lord and Woolf, 1954	Reanalyzed by Cox and Pilcher, 1970, Original value = 59.0 kJ/mol; Heat of hydrolysis; ALS
Δ_subH°	59.9 ± 0.2	kJ/mol	V	Ketellaar and Kruyer, 1943	ALS

Enthalpy of vaporization

Δ_vapH (kJ/mol)	Temperature (K)	Method	Reference	Comment
40.0	423.	A	Stephenson and Malanowski, 1987	Based on data from 419. to 426. K.; AC

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
298.4 to 414.3	7.78435	3335.292	14.533	Stull, 1947	Coefficents calculated by NIST from author's data.

Enthalpy of sublimation

Δ_subH (kJ/mol)	Temperature (K)	Method	Reference	Comment
59.8 ± 0.4	337. to 426.	GSM	Ketelaar and Kruyer, 2010	See also Cox and Pilcher, 1970, 2.; AC
59.9	352.	GSM	Stephenson and Malanowski, 1987	Based on data from 337. to 426. K. See also Ketelaar and Kruyer, 2010.; AC
58.6	356.	A	Stull, 1947	Based on data from 298. to 414. K.; AC
58.3	326.	N/A	Yost and Stone, 1933	Based on data from 278. to 374. K.; AC

Gas phase ion energetics data

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Data compiled as indicated in comments:
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.870 ± 0.001	S	Myer and Samson, 1970	RDSH
10.91	PE	Lake and Thompson, 1970	RDSH
10.91 ± 0.02	PE	Heilbronner, Hornung, et al., 1970	RDSH
10.87 ± 0.02	PI	Dibeler and Liston, 1967	RDSH

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CI⁺	17.6 ± 0.3	N	EI	Herron and Dibeler, 1960	RDSH
CN⁺	18.1 ± 0.1	I	EI	Herron and Dibeler, 1960	RDSH
I⁺	13.62 ± 0.02	CN	PI	Dibeler and Liston, 1967	RDSH
I⁺	9.8 ± 0.1	CN^-	EI	Herron and Dibeler, 1960	RDSH

References

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

Lord and Woolf, 1954
Lord, G.; Woolf, A.A., The cyanogen halides. Part III. Their heats of formation and free energies, J. Chem. Soc., 1954, 2546-2551. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Ketellaar and Kruyer, 1943
Ketellaar, J.A.A.; Kruyer, S., Der dampfdrunk des jodcyans, Rec. Trav. Chim. Pays-Bas, 1943, 62, 550-552. [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]

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]

Ketelaar and Kruyer, 2010
Ketelaar, J.A.A.; Kruyer, S., Der Dampfdruck des Jodcyans, Recl. Trav. Chim. Pays-Bas, 2010, 62, 8, 550-552, https://doi.org/10.1002/recl.19430620810 . [all data]

Cox and Pilcher, 1970, 2
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press Inc., London, 1970, 643. [all data]

Yost and Stone, 1933
Yost, Don M.; Stone, William E., The Complex Ions Formed by Iodine Cyanide with Cyanide and Iodide Ions. The Vapor Pressure, Free Energy and Dissociation of Iodine Cyanide, J. Am. Chem. Soc., 1933, 55, 5, 1889-1895, https://doi.org/10.1021/ja01332a015 . [all data]

Myer and Samson, 1970
Myer, J.A.; Samson, J.A.R., Vacuum-ultraviolet absorption cross sections of CO, HCI, and ICN between 1050 and 2100 A, J. Chem. Phys., 1970, 52, 266. [all data]

Lake and Thompson, 1970
Lake, R.F.; Thompson, H., The photoelectron spectra of some molecules containing the C N group, Proc. Roy. Soc. (London), 1970, A317, 187. [all data]

Heilbronner, Hornung, et al., 1970
Heilbronner, E.; Hornung, V.; Muszkat, K.A., Die Photoelektron-Spektren von Chlor-, Brom- und Jodcyan, Helv. Chim. Acta, 1970, 53, 347. [all data]

Dibeler and Liston, 1967
Dibeler, V.H.; Liston, S.K., Mass-spectrometric study of photoionization. VIII.Dicyanogen and the cyanogen halides, J. Chem. Phys., 1967, 47, 4548. [all data]

Herron and Dibeler, 1960
Herron, J.T.; Dibeler, V.H., Electron impact study of the cyanogen halides, J. Am. Chem. Soc., 1960, 82, 1555. [all data]

Notes

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Symbols used in this document:

AE	Appearance energy
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_subH	Enthalpy of sublimation
Δ_subH°	Enthalpy of sublimation at standard conditions
Δ_vapH	Enthalpy of vaporization
Δ_vapH°	Enthalpy of vaporization at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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