HOCO+

Formula: CHO₂⁺
Molecular weight: 45.0169
CAS Registry Number: 638-71-1
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Other data available:
- Ion clustering data
- Vibrational and/or electronic energy levels
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Reaction thermochemistry data

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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Individual Reactions

CHO₂⁺ + = (CHO₂⁺ • )

By formula: CHO₂⁺ + CO₂ = (CHO₂⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	82.8	kJ/mol	PHPMS	Szulejko and McMahon, 1992	gas phase
Δ_rH°	75.3	kJ/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase
Δ_rH°	79.9	kJ/mol	PHPMS	Jennings, Headley, et al., 1982	gas phase
Δ_rH°	84.1	kJ/mol	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	111.	J/mol*K	PHPMS	Szulejko and McMahon, 1992	gas phase
Δ_rS°	92.9	J/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase
Δ_rS°	113.	J/mol*K	PHPMS	Jennings, Headley, et al., 1982	gas phase
Δ_rS°	101.	J/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase

(CHO₂⁺ • 2) + = (CHO₂⁺ • 3)

By formula: (CHO₂⁺ • 2CO₂) + CO₂ = (CHO₂⁺ • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	25.	kJ/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	100.	J/mol*K	N/A	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated

(CHO₂⁺ • ) + = (CHO₂⁺ • 2)

By formula: (CHO₂⁺ • CO₂) + CO₂ = (CHO₂⁺ • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	29.	kJ/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	96.2	J/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase

References

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Szulejko and McMahon, 1992
Szulejko, J.; McMahon, T.B., personal communication, 1992. [all data]

Hiraoka, Shoda, et al., 1986
Hiraoka, K.; Shoda, T.; Morise, K.; Yamabe, S.; Kawai, E.; Hirao, K., Stability and structure of cluster ions in the gas phase: Carbon dioxide with Cl^-, H₃O⁺, HCO₂⁺ and HCO⁺, J. Chem. Phys., 1986, 84, 2091. [all data]

Jennings, Headley, et al., 1982
Jennings, K.R.; Headley, J.V.; Mason, R.S., The Temperature Dependence of Ion - Molecule Association Reactions, Int. J. Mass. Spectrom. Ion Phys, 1982, 45, 315. [all data]

Meot-Ner (Mautner) and Field, 1977
Meot-Ner (Mautner), M.; Field, F.H., Proton Affinity and Ion - Molecule Clustering in CO2 and CS2. Applications in Martian Ionospheric Chemistry, J. Chem. Phys., 1977, 66, 10, 4527, https://doi.org/10.1063/1.433706 . [all data]

Notes

Go To: Top, Reaction thermochemistry data, References

Symbols used in this document:

Δ_rH° Enthalpy of reaction at standard conditions

Δ_rS° Entropy of reaction at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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Δ_rH°	Enthalpy of reaction at standard conditions
Δ_rS°	Entropy of reaction at standard conditions