Isothiocyanic acid
- Formula: CHNS
- Molecular weight: 59.090
- IUPAC Standard InChI: InChI=1S/CNS/c2-1-3/q-1
- IUPAC Standard InChIKey: ZBKFYXZXZJPWNQ-UHFFFAOYSA-N
- CAS Registry Number: 3129-90-6
- Chemical structure:
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Reaction thermochemistry data
Go To: Top, 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 by: John E. Bartmess
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.
Individual Reactions
CNS- + =
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | <325.3 ± 1.1 | kcal/mol | D-EA | Bradforth, Kim, et al., 1993 | gas phase; Acid HNCS. HSCN up by ca. 8 kcal/mol |
| ΔrH° | 328.6 ± 5.1 | kcal/mol | G+TS | Bierbaum, Grabowski, et al., 1984 | gas phase; Acid: HNCS |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | <317.6 ± 1.4 | kcal/mol | H-TS | Bradforth, Kim, et al., 1993 | gas phase; Acid HNCS. HSCN up by ca. 8 kcal/mol |
| ΔrG° | 320.9 ± 5.0 | kcal/mol | IMRB | Bierbaum, Grabowski, et al., 1984 | gas phase; Acid: HNCS |
Gas phase ion energetics data
Go To: Top, Reaction thermochemistry 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:
L - Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
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 CHNS+ (ion structure unspecified)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| IE (evaluated) | ≤9.92 | eV | N/A | N/A | L |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| ≤9.92 | PI | Ruscic and Berkowitz, 1994 | LL |
| 10.1 ± 0.1 | PE | Eland, 1970 | RDSH |
| 9.94 ± 0.02 | PE | Cradock, Ebsworth, et al., 1972 | Vertical value; LLK |
Appearance energy determinations
| Ion | AE (eV) | Other Products | Method | Reference | Comment |
|---|---|---|---|---|---|
| NCS+ | 14.903 ± 0.009 | H | PI | Ruscic and Berkowitz, 1994 | LL |
| CS+ | 16.884 | ? | PI | Ruscic and Berkowitz, 1994 | LL |
| HS+ | 15.131 | CN | PI | Ruscic and Berkowitz, 1994 | LL |
| NS+ | 16.879 | ? | PI | Ruscic and Berkowitz, 1994 | LL |
| S+ | 13.205 ± 0.014 | ? | PI | Ruscic and Berkowitz, 1994 | LL |
De-protonation reactions
CNS- + =
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | <325.3 ± 1.1 | kcal/mol | D-EA | Bradforth, Kim, et al., 1993 | gas phase; Acid HNCS. HSCN up by ca. 8 kcal/mol; B |
| ΔrH° | 328.6 ± 5.1 | kcal/mol | G+TS | Bierbaum, Grabowski, et al., 1984 | gas phase; Acid: HNCS; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | <317.6 ± 1.4 | kcal/mol | H-TS | Bradforth, Kim, et al., 1993 | gas phase; Acid HNCS. HSCN up by ca. 8 kcal/mol; B |
| ΔrG° | 320.9 ± 5.0 | kcal/mol | IMRB | Bierbaum, Grabowski, et al., 1984 | gas phase; Acid: HNCS; B |
References
Go To: Top, Reaction thermochemistry 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.
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]
Bierbaum, Grabowski, et al., 1984
Bierbaum, V.M.; Grabowski, J.J.; DePuy, C.H.,
Gas-phase synthesis and reactions of nitrogen- and sulfur-containing anions,
J. Phys. Chem., 1984, 88, 1389. [all data]
Ruscic and Berkowitz, 1994
Ruscic, B.; Berkowitz, J.,
The H-NCS bond energy, Hf(NCS), and IP(NCS) from photoionization mass spectrometric studies of HNCS, NCS, and (NCS)2,
J. Chem. Phys., 1994, 101, 7975. [all data]
Eland, 1970
Eland, J.H.D.,
The photoelectron spectra of isocyanic acid and related compounds,
Phil. Trans. Roy. Soc. (London), 1970, A268, 87. [all data]
Cradock, Ebsworth, et al., 1972
Cradock, S.; Ebsworth, E.A.V.; Murdoch, J.D.,
Photoelectron spectra of some Group 4 pseudohalides and related compounds,
J. Chem. Soc. Faraday Trans. 2, 1972, 68, 86. [all data]
Notes
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy 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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