Carbon dioxide

Formula: CO₂
Molecular weight: 44.0095
IUPAC Standard InChI: InChI=1S/CO2/c2-1-3
IUPAC Standard InChIKey: CURLTUGMZLYLDI-UHFFFAOYSA-N
CAS Registry Number: 124-38-9
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript.
Isotopologues:
- Carbon dioxide (¹²C¹⁶O₂)
Other names: Carbon oxide (CO2); Carbonic acid, gas; Carbonic anhydride; Dry ice; CO2; Anhydride carbonique; Carbonica; Kohlendioxyd; Kohlensaure; UN 1013; UN 1845; UN 2187; Cardice; Dricold; Drikold; Carbonic acid anhydride; Khladon 744; R 744
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Information on this page:
Other data available:
- Phase change data
- Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 100, reactions 101 to 143
- Henry's Law data
- IR Spectrum
- Gas Chromatography
- Fluid Properties
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Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-94.051 ± 0.031	kcal/mol	Review	Cox, Wagman, et al., 1984	CODATA Review value
Δ_fH°_gas	-94.054	kcal/mol	Review	Chase, 1998	Data last reviewed in September, 1965
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	51.0958 ± 0.0024	cal/mol*K	Review	Cox, Wagman, et al., 1984	CODATA Review value
S°_{gas,1 bar}	51.097	cal/mol*K	Review	Chase, 1998	Data last reviewed in September, 1965

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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Temperature (K)	298. to 1200.	1200. to 6000.
A	5.974511	13.90210
B	13.19000	0.650113
C	-8.052431	-0.117660
D	1.899711	0.009284
E	-0.032657	-1.540941
F	-96.46451	-101.7970
G	54.55141	63.00490
H	-94.05411	-94.05411
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in September, 1965	Data last reviewed in September, 1965

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Ion clustering data, Mass spectrum (electron ionization), 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:
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
B - John E. Bartmess

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	13.777 ± 0.001	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	129.2	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	123.3	kcal/mol	N/A	Hunter and Lias, 1998	HL

Electron affinity determinations

EA (eV)	Method	Reference	Comment
-0.599986	EIAE	Knapp, Echt, et al., 1986	Unbound but in -0.3 eV well, from (CO2)n; B
-1.60 ± 0.10	NBIE	Compton, Reinhardt, et al., 1975	B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
13.778 ± 0.002	PE	Wang, Reutt, et al., 1988	LL
13.78	PE	Kimura, Katsumata, et al., 1981	LLK
13.776 ± 0.002	PE	Potts and Fattahallah, 1980	LLK
13. ± 1.	PI	Hitchcock, Brion, et al., 1980	LLK
13.89 ± 0.03	EI	Sahini, Constantin, et al., 1978	LLK
13.79 ± 0.05	EI	Mark and Hille, 1978	LLK
13.77	PI	Jones and Taylor, 1978	LLK
13.777 ± 0.002	PE	Frey, Gotchev, et al., 1977	LLK
13.83 ± 0.05	EI	Bussieres and Marmet, 1977	LLK
13.788	PE	Kronebusch and Berkowitz, 1976	LLK
13.776 ± 0.002	TE	Batten, Taylor, et al., 1976	LLK
13.774 ± 0.003	PI	Parr and Taylor, 1974	LLK
13.9 ± 0.2	EI	Semenov, Volkov, et al., 1973	LLK
13.776 ± 0.008	PI	Parr and Taylor, 1973	LLK
13.78	PE	Natalis, 1973	LLK
13.773 ± 0.002	PI	McCulloh, 1973	LLK
13.80 ± 0.01	PE	Frost, Lee, et al., 1973	LLK
13.788 ± 0.005	PE	Brundle and Turner, 1969	RDSH
13.78 ± 0.01	PE	Eland and Danby, 1968	RDSH
13.77	PE	Spohr and Puttkamer, 1967	RDSH
13.75 ± 0.05	EI	Carette, 1967	RDSH
13.767 ± 0.003	PI	Nakata, Watanabe, et al., 1965	RDSH
13.77 ± 0.03	S	Tanaka, Jursa, et al., 1960	RDSH
13.773	PE	Eland and Berkowitz, 1977	Vertical value; LLK
13.78	PE	Benoit and Harrison, 1977	Vertical value; LLK
13.78	PE	Schweig and Thiel, 1974	Vertical value; LLK
13.79	PE	Potts and Williams, 1974	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
C⁺	25. ± 2.	O₂	PI	Hitchcock, Brion, et al., 1980	LLK
C⁺	22.7 ± 0.2	O₂	EI	Bussieres and Marmet, 1977	LLK
C⁺	27.8 ± 0.1	2O	EI	Bussieres and Marmet, 1977	LLK
C⁺	24.6 ± 1.0	O₂	EI	Crowe and McConkey, 1974	LLK
C⁺	28.4 ± 0.6	2O	EI	Cuthbert, Farren, et al., 1968	RDSH
C⁺	14.2 ± 0.5	2O	EI	Cuthbert, Farren, et al., 1968	RDSH
C⁺	23.2 ± 0.5	O₂	EI	Cuthbert, Farren, et al., 1968	RDSH
CO⁺	19. ± 2.	O	PI	Hitchcock, Brion, et al., 1980	LLK
CO⁺	19.466	O	PE	Eland and Berkowitz, 1977, 2	LLK
CO⁺	19.42 ± 0.075	O	EI	Bussieres and Marmet, 1977	LLK
CO⁺	19.466	O	PE	Kronebusch and Berkowitz, 1976	LLK
CO⁺	20.9 ± 1.0	O	EI	Crowe and McConkey, 1974	LLK
CO⁺	29.0	O	PI	Samson and Gardner, 1973	LLK
O⁺	19. ± 1.	CO	PI	Hitchcock, Brion, et al., 1980	LLK
O⁺	19.071	CO	PE	Eland and Berkowitz, 1977, 2	LLK
O⁺	19.05 ± 0.05	CO	EI	Bussieres and Marmet, 1977	LLK
O⁺	19.067	CO	PE	Kronebusch and Berkowitz, 1976	LLK
O⁺	19.393 ± 0.008	?	PI	Parr and Taylor, 1974	LLK
O⁺	22.6 ± 1.0	CO	EI	Crowe and McConkey, 1974	LLK
O⁺	19.10 ± 0.01	CO	PI	Dibeler and Walker, 1967	RDSH

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
RCD - Robert C. Dunbar

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

+ Carbon dioxide = ( • )

By formula: Br^- + CO₂ = (Br^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.3 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995	gas phase; Affinity: shift in apparent EA from lesser-solvated ion. Ignores any neutral-neutral bond.; B
Δ_rH°	6.7 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.5	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.8 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • Carbon dioxide ) + = ( • 2)

By formula: (Br^- • CO₂) + CO₂ = (Br^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.1 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	6.0 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.0	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.3 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (Br^- • 2CO₂) + CO₂ = (Br^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.1 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (Br^- • 3CO₂) + CO₂ = (Br^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.2 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (Br^- • 4CO₂) + CO₂ = (Br^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.2 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (Br^- • 5CO₂) + CO₂ = (Br^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.0 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 6 Carbon dioxide ) + = ( • 7)

By formula: (Br^- • 6CO₂) + CO₂ = (Br^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.6 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 7 Carbon dioxide ) + = ( • 8)

By formula: (Br^- • 7CO₂) + CO₂ = (Br^- • 8CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.7 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 8 Carbon dioxide ) + = ( • 9)

By formula: (Br^- • 8CO₂) + CO₂ = (Br^- • 9CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.8 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 9 Carbon dioxide ) + = ( • 10)

By formula: (Br^- • 9CO₂) + CO₂ = (Br^- • 10CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.8 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 10 Carbon dioxide ) + = ( • 11)

By formula: (Br^- • 10CO₂) + CO₂ = (Br^- • 11CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.5 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

+ Carbon dioxide = ( • )

By formula: CHO⁺ + CO₂ = (CHO⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.6	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.4	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

( • Carbon dioxide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.2	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.7	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

( • 2 Carbon dioxide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.9	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.7	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (CHO⁺ • 3CO₂) + CO₂ = (CHO⁺ • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.4	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.	cal/mol*K	N/A	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated; M

CHO₂⁺ + Carbon dioxide = (CHO₂⁺ • )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.8	kcal/mol	PHPMS	Szulejko and McMahon, 1992	gas phase; M
Δ_rH°	18.0	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Δ_rH°	19.1	kcal/mol	PHPMS	Jennings, Headley, et al., 1982	gas phase; M
Δ_rH°	20.1	kcal/mol	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.6	cal/mol*K	PHPMS	Szulejko and McMahon, 1992	gas phase; M
Δ_rS°	22.2	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Δ_rS°	27.1	cal/mol*K	PHPMS	Jennings, Headley, et al., 1982	gas phase; M
Δ_rS°	24.2	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M

(CHO₂⁺ • Carbon dioxide ) + = (CHO₂⁺ • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.9	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.0	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

(CHO₂⁺ • 2 Carbon dioxide ) + = (CHO₂⁺ • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.9	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.	cal/mol*K	N/A	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated; M

( • 4294967295 Carbon dioxide ) + =

By formula: (CHO₂^- • 4294967295CO₂) + CO₂ = CHO₂^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	51.6 ± 2.3	kcal/mol	N/A	Caldwell, Renneboog, et al., 1989	gas phase; B

+ Carbon dioxide = ( • )

By formula: CH₃⁺ + CO₂ = (CH₃⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	49.4	kcal/mol	PHPMS	McMahon, Heinis, et al., 1988	gas phase; switching reaction(CH3+)N2, Entropy change calculated or estimated, uses MCA(N2) = 48.3 kcal/mol; Foster, Williamson, et al., 1974; M

CH₆N⁺ + Carbon dioxide = (CH₆N⁺ • )

By formula: CH₆N⁺ + CO₂ = (CH₆N⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.2	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.4	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

CN^- + Carbon dioxide = (CN^- • )

By formula: CN^- + CO₂ = (CN^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.30 ± 0.80	kcal/mol	TDAs	Larson, Szulejko, et al., 1988	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	31.5	cal/mol*K	PHPMS	Larson, Szulejko, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.90 ± 0.20	kcal/mol	TDAs	Larson, Szulejko, et al., 1988	gas phase; B

+ Carbon dioxide = ( • )

By formula: CO₂⁺ + CO₂ = (CO₂⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16. ± 1.	kcal/mol	AVG	N/A	Average of 7 out of 10 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.1	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rS°	18.6	cal/mol*K	DT	Illies, 1988	gas phase; Δ_rH(0 K)=15.9 kcal/mol; M
Δ_rS°	19.5	cal/mol*K	DT	Van Koppen, Kemper, et al., 1983	gas phase; M
Δ_rS°	22.8	cal/mol*K	PHPMS	Headley, Mason, et al., 1982	gas phase; M
Δ_rS°	21.1	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M

( • Carbon dioxide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.6 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rH°	8.3	kcal/mol	EI	Cameron, Aitken, et al., 1994	gas phase; M
Δ_rH°	3.3	kcal/mol	PI	Linn and Ng, 1981	gas phase; M
Δ_rH°	6.0	kcal/mol	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	14.1	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rS°	24.0	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M

( • 2 Carbon dioxide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.0	kcal/mol	EI	Cameron, Aitken, et al., 1994	gas phase; M
Δ_rH°	5.1 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rH°	2.8	kcal/mol	PI	Linn and Ng, 1981	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.1	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (CO₂⁺ • 3CO₂) + CO₂ = (CO₂⁺ • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.8 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (CO₂⁺ • 4CO₂) + CO₂ = (CO₂⁺ • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.3 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (CO₂⁺ • 5CO₂) + CO₂ = (CO₂⁺ • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.0	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.	cal/mol*K	N/A	Hiraoka, Nakajima, et al., 1988	gas phase; Entropy change calculated or estimated; M

CO₃^- + Carbon dioxide = C₂O₅^-

By formula: CO₃^- + CO₂ = C₂O₅^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.90 ± 0.20	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Δ_rH°	7.10 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.0 ± 2.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Δ_rG°	0.60 ± 0.20	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B

CO₃^- + Carbon dioxide = (CO₃^- • )

By formula: CO₃^- + CO₂ = (CO₃^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.9 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.3	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • Carbon dioxide ) + = (CO₃^- • 2)

By formula: (CO₃^- • CO₂) + CO₂ = (CO₃^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.9	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • 2 Carbon dioxide ) + = (CO₃^- • 3)

By formula: (CO₃^- • 2CO₂) + CO₂ = (CO₃^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.5 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.9	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • 3 Carbon dioxide ) + = (CO₃^- • 4)

By formula: (CO₃^- • 3CO₂) + CO₂ = (CO₃^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.2 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.3	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • 4 Carbon dioxide ) + = (CO₃^- • 5)

By formula: (CO₃^- • 4CO₂) + CO₂ = (CO₃^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.8 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.0	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • 5 Carbon dioxide ) + = (CO₃^- • 6)

By formula: (CO₃^- • 5CO₂) + CO₂ = (CO₃^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.9	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M

(CO₃^- • 6 Carbon dioxide ) + = (CO₃^- • 7)

By formula: (CO₃^- • 6CO₂) + CO₂ = (CO₃^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.45	kcal/mol	PHPMS	Hiraoka and Yamabe, 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.	cal/mol*K	N/A	Hiraoka and Yamabe, 1992	gas phase; Entropy change calculated or estimated; M

( • 4294967295 Carbon dioxide ) + =

By formula: (C₂H₂O₂^- • 4294967295CO₂) + CO₂ = C₂H₂O₂^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	61.7 ± 2.7	kcal/mol	CIDT	Wenthold and Squires, 1994	gas phase; B

( • 4294967295 Carbon dioxide ) + =

By formula: (C₂H₃O₂^- • 4294967295CO₂) + CO₂ = C₂H₃O₂^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	59.7 ± 2.5	kcal/mol	CIDC	Wenthold and Squires, 1994	gas phase; B

C₂H₈N⁺ + Carbon dioxide = (C₂H₈N⁺ • )

By formula: C₂H₈N⁺ + CO₂ = (C₂H₈N⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.2	kcal/mol	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.8	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1978	gas phase; M

C₂O₅^- + 2 Carbon dioxide = C₃O₇^-

By formula: C₂O₅^- + 2CO₂ = C₃O₇^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.7 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.4 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

C₃O₇^- + 3 Carbon dioxide = C₄O₉^-

By formula: C₃O₇^- + 3CO₂ = C₄O₉^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.5 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

C₄O₉^- + 4 Carbon dioxide = C₅O₁₁^-

By formula: C₄O₉^- + 4CO₂ = C₅O₁₁^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.2 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.5 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

C₅O₁₁^- + 5 Carbon dioxide = C₆O₁₃^-

By formula: C₅O₁₁^- + 5CO₂ = C₆O₁₃^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

C₆O₁₃^- + 6 Carbon dioxide = C₇O₁₅^-

By formula: C₆O₁₃^- + 6CO₂ = C₇O₁₅^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.7 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.9 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

C₇O₁₅^- + 7 Carbon dioxide = C₈O₁₇^-

By formula: C₇O₁₅^- + 7CO₂ = C₈O₁₇^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.5 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; Estimated entropy; single temperature measurement; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-2.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; Estimated entropy; single temperature measurement; B

(Ca⁺² • 4 Carbon dioxide • ) + = (Ca⁺² • 5 • )

By formula: (Ca⁺² • 4CO₂ • CCaO₃) + CO₂ = (Ca⁺² • 5CO₂ • CCaO₃)

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
7.6	296.	FA	Spears and Fehsenfeld, 1972	gas phase; M

(Ca⁺² • 5 Carbon dioxide ) + = (Ca⁺² • 6)

By formula: (Ca⁺² • 5CO₂) + CO₂ = (Ca⁺² • 6CO₂)

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.1	296.	FA	Spears and Fehsenfeld, 1972	gas phase; M

+ Carbon dioxide = ( • )

By formula: Cl^- + CO₂ = (Cl^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.80 ± 0.50	kcal/mol	PDis	Arnold, Bradforth, et al., 1995	gas phase; Affinity: shift in apparent EA from lesser-solvated ion. Ignores any neutral-neutral bond.; B
Δ_rH°	7.60	kcal/mol	TDEq	Hiraoka, Shoda, et al., 1986	gas phase; B,M
Δ_rH°	8.00 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.2	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Δ_rS°	19.6	cal/mol*K	HPMS	Keesee, Lee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.10	kcal/mol	TDEq	Hiraoka, Shoda, et al., 1986	gas phase; B
Δ_rG°	2.10 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B

( • Carbon dioxide ) + = ( • 2)

By formula: (Cl^- • CO₂) + CO₂ = (Cl^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.2 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rH°	7.20	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.8	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.4 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rG°	1.00	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (Cl^- • 2CO₂) + CO₂ = (Cl^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.8 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rH°	6.80	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.4	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.1 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rG°	0.10	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (Cl^- • 3CO₂) + CO₂ = (Cl^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.40	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; entropy estimated.; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.	cal/mol*K	N/A	Hiraoka, Shoda, et al., 1986	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.80	kcal/mol	TDAs	Hiraoka, Shoda, et al., 1986	gas phase; entropy estimated.; B

+ Carbon dioxide = ( • )

By formula: Cs⁺ + CO₂ = (Cs⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.2	kcal/mol	DT	McKnight and Sawina, 1972	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	14.3	cal/mol*K	DT	McKnight and Sawina, 1972	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
2.4	301.	HPMS	Banic and Iribarne, 1985	gas phase; electric fields; M

( • ) + Carbon dioxide = ( • • )

By formula: (Cs⁺ • H₂O) + CO₂ = (Cs⁺ • CO₂ • H₂O)

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
1.2	301.	HPMS	Banic and Iribarne, 1985	gas phase; electric fields; M

+ Carbon dioxide = ( • )

By formula: F^- + CO₂ = (F^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	32.07	kcal/mol	N/A	Arnold, Bradforth, et al., 1995	gas phase; B
Δ_rH°	32.3 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Δ_rH°	31.7 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1985	gas phase; B,M
Δ_rH°	33.0 ± 3.0	kcal/mol	IMRE	McMahon and Northcott, 1978	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.7	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Δ_rS°	24.	cal/mol*K	N/A	Larson and McMahon, 1985	gas phase; switching reaction,Thermochemical ladder(F-)H2O, Entropy change calculated or estimated; Arshadi, Yamdagni, et al., 1970; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	24.3 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rG°	24.5 ± 2.0	kcal/mol	IMRE	Larson and McMahon, 1985	gas phase; B,M
Δ_rG°	11.6	kcal/mol	FA	Spears and Ferguson, 1973	gas phase; DG>; M

( • Carbon dioxide ) + = ( • 2)

By formula: (F^- • CO₂) + CO₂ = (F^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.3 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.2	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.9 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (F^- • 2CO₂) + CO₂ = (F^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.2 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.6	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.5 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (F^- • 3CO₂) + CO₂ = (F^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.8 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.2 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (F^- • 4CO₂) + CO₂ = (F^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.6 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.3	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.0 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (F^- • 5CO₂) + CO₂ = (F^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.3 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.5	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.4 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 6 Carbon dioxide ) + = ( • 7)

By formula: (F^- • 6CO₂) + CO₂ = (F^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.9	kcal/mol	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.	cal/mol*K	N/A	Hiraoka, Mizuse, et al., 1987	gas phase; Entropy change calculated or estimated; M

+ Carbon dioxide = ( • )

By formula: Fe⁺ + CO₂ = (Fe⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.3 ± 1.0	kcal/mol	CIDT	Rodgers and Armentrout, 2000	RCD

HO^- + Carbon dioxide = (HO^- • )

By formula: HO^- + CO₂ = (HO^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	50.9 ± 2.5	kcal/mol	CIDT	Squires, 1992	gas phase; Dissociative protonation threshold at nPrSH, 9 kcal> calc. CIDC(HOCO2-..HSH) = 7:1 HOCO2-; B
Δ_rH°	87.60	kcal/mol	Endo	Hierl and Paulson, 1984	gas phase; Implies ΔHacid = 291.4, anion appears too stable - JEB; B

+ Carbon dioxide = ( • )

By formula: HO^- + CO₂ = (HO^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	88.	kcal/mol	CID	Hierl and Paulson, 1984	gas phase; M

+ Carbon dioxide = ( • )

By formula: H₃O⁺ + CO₂ = (H₃O⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.3	kcal/mol	PHPMS	Szulejko and McMahon, 1992	gas phase; M
Δ_rH°	15.3	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Δ_rH°	14.4	kcal/mol	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	PHPMS	Szulejko and McMahon, 1992	gas phase; M
Δ_rS°	24.6	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Δ_rS°	20.7	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; M

( • Carbon dioxide ) + = ( • 2)

By formula: (H₃O⁺ • CO₂) + CO₂ = (H₃O⁺ • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.4	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.5	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (H₃O⁺ • 2CO₂) + CO₂ = (H₃O⁺ • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.5	kcal/mol	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.9	cal/mol*K	PHPMS	Hiraoka, Shoda, et al., 1986	gas phase; M

+ Carbon dioxide = ( • )

By formula: H₄N⁺ + CO₂ = (H₄N⁺ • CO₂)

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
2.3	296.	FA	Spears and Fehsenfeld, 1972	gas phase; M

( • 2) + Carbon dioxide = ( • • 2)

By formula: (H₄N⁺ • 2H₂O) + CO₂ = (H₄N⁺ • CO₂ • 2H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.3	kcal/mol	HPMS	Banic and Iribarne, 1985	gas phase; electric fields; M

+ Carbon dioxide = ( • )

By formula: I^- + CO₂ = (I^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.7 ± 1.8	kcal/mol	N/A	Piani, Becucci, et al., 2008	gas phase; Stated electron affinity is the Vertical Detachment Energy; B
Δ_rH°	4.0 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	4.7 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Δ_rH°	3.20	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Δ_rH°	5.60 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.4	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Δ_rS°	18.2	cal/mol*K	HPMS	Keesee, Lee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.7 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Δ_rG°	0.80 ± 0.10	kcal/mol	TDAs	Banic and Iribarne, 1985	gas phase; B,M
Δ_rG°	0.40 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B

( • Carbon dioxide ) + = ( • 2)

By formula: (I^- • CO₂) + CO₂ = (I^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.6 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	4.7 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Δ_rH°	2.60	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.7 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (I^- • 2CO₂) + CO₂ = (I^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.20	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Δ_rH°	3.7 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	4.6 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.4	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.6 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (I^- • 3CO₂) + CO₂ = (I^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.80	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Δ_rH°	3.6 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	4.5 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.0 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (I^- • 4CO₂) + CO₂ = (I^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.70	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Δ_rH°	3.1 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	4.3 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.0	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.4 ± 2.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1987	gas phase; B

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (I^- • 5CO₂) + CO₂ = (I^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.0 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	1.80	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B
Δ_rH°	4.2	kcal/mol	PHPMS	Hiraoka, Mizuse, et al., 1987	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.	cal/mol*K	N/A	Hiraoka, Mizuse, et al., 1987	gas phase; Entropy change calculated or estimated; M

( • 6 Carbon dioxide ) + = ( • 7)

By formula: (I^- • 6CO₂) + CO₂ = (I^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.3 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	1.90	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B

( • 7 Carbon dioxide ) + = ( • 8)

By formula: (I^- • 7CO₂) + CO₂ = (I^- • 8CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.1 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B
Δ_rH°	1.90	kcal/mol	N/A	Gomez, Taylor, et al., 2002	gas phase; EA=Vertical Detachment Energy. Affinity is stepwise difference in EAs.; B

( • 8 Carbon dioxide ) + = ( • 9)

By formula: (I^- • 8CO₂) + CO₂ = (I^- • 9CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.8 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 9 Carbon dioxide ) + = ( • 10)

By formula: (I^- • 9CO₂) + CO₂ = (I^- • 10CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.9 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 10 Carbon dioxide ) + = ( • 11)

By formula: (I^- • 10CO₂) + CO₂ = (I^- • 11CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.0 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 11 Carbon dioxide ) + = ( • 12)

By formula: (I^- • 11CO₂) + CO₂ = (I^- • 12CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

( • 12 Carbon dioxide ) + = ( • 13)

By formula: (I^- • 12CO₂) + CO₂ = (I^- • 13CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.1 ± 2.0	kcal/mol	PDis	Arnold, Bradforth, et al., 1995, 2	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

+ Carbon dioxide = ( • )

By formula: K⁺ + CO₂ = (K⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.5	kcal/mol	HPMS	Castleman and Keesee, 1981	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	15.2	cal/mol*K	HPMS	Castleman and Keesee, 1981	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
3.7	310.	DT	Keller and Beyer, 1971	gas phase; low E/N; M

Kr⁺ + Carbon dioxide = (Kr⁺ • )

By formula: Kr⁺ + CO₂ = (Kr⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	18.9 ± 0.7	kcal/mol	SIFT	Praxmarer, Jordan, et al., 1993	gas phase; switching reaction(Kr+)Kr; Wadt, 1978, Radzig and Smirnov, 1985; M

+ Carbon dioxide = ( • )

By formula: Mg⁺ + CO₂ = (Mg⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.8 ± 1.4	kcal/mol	CIDT	Andersen, Muntean, et al., 2000	RCD

( • Carbon dioxide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.5 ± 0.7	kcal/mol	CIDT	Andersen, Muntean, et al., 2000	RCD

( • 2 Carbon dioxide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.6 ± 1.4	kcal/mol	CIDT	Andersen, Muntean, et al., 2000	RCD

+ Carbon dioxide = ( • )

By formula: NO^- + CO₂ = (NO^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.5 ± 0.3	kcal/mol	DT	Illies, 1988	gas phase; Δ_rH(0 K)=8.60 kcal/mol; M
Δ_rH°	7.7 ± 0.4	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M
Δ_rH°	13.8	kcal/mol	FA	Dunkin, Fehsenfeld, et al., 1971	gas phase; switching reaction(NO+)NO, Δ_rH<; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.0	cal/mol*K	DT	Illies, 1988	gas phase; Δ_rH(0 K)=8.60 kcal/mol; M
Δ_rS°	13.7	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M

( • Carbon dioxide ) + = ( • 2)

By formula: (NO^- • CO₂) + CO₂ = (NO^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.4 ± 0.4	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.1	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (NO^- • 2CO₂) + CO₂ = (NO^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.2 ± 0.4	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.8	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (NO^- • 3CO₂) + CO₂ = (NO^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.7 ± 0.3	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.4	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (NO^- • 4CO₂) + CO₂ = (NO^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.2 ± 0.3	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.9	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1991	gas phase; M

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (NO^- • 5CO₂) + CO₂ = (NO^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.0	kcal/mol	PHPMS	Hiraoka and Yamabe, 1991	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	28.	cal/mol*K	N/A	Hiraoka and Yamabe, 1991	gas phase; Entropy change calculated or estimated; M

+ Carbon dioxide = ( • )

By formula: NO₂^- + CO₂ = (NO₂^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.30 ± 0.20	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Δ_rH°	9.30 ± 0.10	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.2	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Δ_rS°	24.2	cal/mol*K	HPMS	Keesee, Lee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.1 ± 2.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Δ_rG°	2.00 ± 0.20	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B

( • Carbon dioxide ) + = ( • 2)

By formula: (NO₂^- • CO₂) + CO₂ = (NO₂^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.7 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.0	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.0 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (NO₂^- • 2CO₂) + CO₂ = (NO₂^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.3 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.3	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.7 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (NO₂^- • 3CO₂) + CO₂ = (NO₂^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.0 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.9	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.7 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (NO₂^- • 4CO₂) + CO₂ = (NO₂^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.2 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.3	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (NO₂^- • 5CO₂) + CO₂ = (NO₂^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.9 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.1	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-2.0 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 6 Carbon dioxide ) + = ( • 7)

By formula: (NO₂^- • 6CO₂) + CO₂ = (NO₂^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.4 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-2.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 7 Carbon dioxide ) + = ( • 8)

By formula: (NO₂^- • 7CO₂) + CO₂ = (NO₂^- • 8CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.2 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-2.3 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

+ Carbon dioxide = ( • )

By formula: NO₃^- + CO₂ = (NO₃^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.70 ± 0.10	kcal/mol	TDAs	Banic and Iribarne, 1985	gas phase; B,M

+ Carbon dioxide = ( • )

By formula: Na⁺ + CO₂ = (Na⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.9	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Δ_rH°	13.7	kcal/mol	FA	Perry, Rowe, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.1	cal/mol*K	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Δ_rS°	19.8	cal/mol*K	FA	Perry, Rowe, et al., 1980	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
6.6	310.	DT	Keller and Beyer, 1971, 2	gas phase; low E/N; M

( • Carbon dioxide ) + = ( • 2)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.0	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.7	cal/mol*K	HPMS	Peterson, Mark, et al., 1984	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.8	310.	DT	Keller and Beyer, 1971, 2	gas phase; low E/N; M

( • 2 Carbon dioxide ) + = ( • 3)

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.7	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.0	cal/mol*K	HPMS	Peterson, Mark, et al., 1984	gas phase; M

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (Na⁺ • 3CO₂) + CO₂ = (Na⁺ • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.4	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	N/A	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
0.7	310.	HPMS	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M

( • ) + Carbon dioxide = ( • • )

By formula: (Na⁺ • H₂O) + CO₂ = (Na⁺ • CO₂ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.6	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.5	cal/mol*K	HPMS	Peterson, Mark, et al., 1984	gas phase; M

( • 2) + Carbon dioxide = ( • • 2)

By formula: (Na⁺ • 2H₂O) + CO₂ = (Na⁺ • CO₂ • 2H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.3	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.9	cal/mol*K	HPMS	Peterson, Mark, et al., 1984	gas phase; M

( • 3) + Carbon dioxide = ( • • 3)

By formula: (Na⁺ • 3H₂O) + CO₂ = (Na⁺ • CO₂ • 3H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.2	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.	cal/mol*K	N/A	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.3	kcal/mol	HPMS	Peterson, Mark, et al., 1984	gas phase; Entropy change calculated or estimated; M

O^- + Carbon dioxide = (O^- • )

By formula: O^- + CO₂ = (O^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	48. ± 10.	kcal/mol	AVG	N/A	Average of 8 out of 9 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	48.0 ± 5.0	kcal/mol	IMRE	Adams and Bohme, 1970	gas phase; O₃^- + CO₂ <=> CO₃^- + O₂; B

(O^- • Carbon dioxide ) + = (O^- • 2)

By formula: (O^- • CO₂) + CO₂ = (O^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.1	kcal/mol	HPMS	Keesee, Lee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.8	cal/mol*K	HPMS	Keesee, Lee, et al., 1980	gas phase; M

(O^- • ) + Carbon dioxide = (O^- • • )

By formula: (O^- • H₂O) + CO₂ = (O^- • CO₂ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	36.4	kcal/mol	PDiss	Roehl, Snodgrass, et al., 1991	gas phase; Δ_rH>; M

+ Carbon dioxide = ( • )

By formula: O₂⁺ + CO₂ = (O₂⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.8 ± 0.9	kcal/mol	AVG	N/A	Average of 4 out of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.5	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rS°	18.9	cal/mol*K	DT	Illies, 1988	gas phase; Δ_rH(0 K)=9.80 kcal/mol; M
Δ_rS°	20.7	cal/mol*K	N/A	Dotan, Davidson, et al., 1978	gas phase; switching reaction(O2+)O2, Entropy change calculated or estimated; Conway and Janik, 1970; M
Δ_rS°	20.	cal/mol*K	N/A	Meot-Ner (Mautner) and Field, 1977	gas phase; Entropy change calculated or estimated, DG>, Δ_rH>; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.4	kcal/mol	DT	Rakshit and Warneck, 1981	gas phase; M
Δ_rG°	4.3	kcal/mol	FA	Dotan, Davidson, et al., 1978	gas phase; switching reaction(O2+)O2, Entropy change calculated or estimated; Conway and Janik, 1970; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.4	600.	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; Entropy change calculated or estimated, DG>, Δ_rH>; M

( • Carbon dioxide ) + = ( • 2)

By formula: (O₂⁺ • CO₂) + CO₂ = (O₂⁺ • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.6 ± 0.5	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rH°	7.5	kcal/mol	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; Entropy change is questionable; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.7	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Δ_rS°	15.	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Field, 1977	gas phase; Entropy change is questionable; M

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (O₂⁺ • 2CO₂) + CO₂ = (O₂⁺ • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.2 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.8	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (O₂⁺ • 3CO₂) + CO₂ = (O₂⁺ • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.1 ± 0.3	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.6	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (O₂⁺ • 4CO₂) + CO₂ = (O₂⁺ • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.5 ± 0.5	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.0	cal/mol*K	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; M

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (O₂⁺ • 5CO₂) + CO₂ = (O₂⁺ • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.0	kcal/mol	PHPMS	Hiraoka, Nakajima, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	N/A	Hiraoka, Nakajima, et al., 1988	gas phase; Entropy change calculated or estimated; M

+ Carbon dioxide = ( • )

By formula: O₂^- + CO₂ = (O₂^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.00 ± 0.20	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Δ_rH°	17.7 ± 1.8	kcal/mol	IMRE	Pack and Phelps, 1966	gas phase; Corrected with more recent EA(O2) = 0.45 eV; B,M
Δ_rH°	25.4 ± 4.6	kcal/mol	PDis	Vestal and Mauclaire, 1977	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.2	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Δ_rS°	21.	cal/mol*K	DT	Pack and Phelps, 1966	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	11.7 ± 2.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B
Δ_rG°	12.2 ± 1.2	kcal/mol	IMRE	Pack and Phelps, 1966	gas phase; Corrected with more recent EA(O2) = 0.45 eV; B
Δ_rG°	10.0	kcal/mol	FA	Adams and Bohme, 1970	gas phase; switching reaction(O2-)O2; Conway and Nesbit, 1968; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
12.9	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; switching reaction(O2-)H2O; Arshadi and Kebarle, 1970; M

( • Carbon dioxide ) + = ( • 2)

By formula: (O₂^- • CO₂) + CO₂ = (O₂^- • 2CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.60 ± 0.20	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.2	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 2 Carbon dioxide ) + = ( • 3)

By formula: (O₂^- • 2CO₂) + CO₂ = (O₂^- • 3CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.3 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.0	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.6 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 3 Carbon dioxide ) + = ( • 4)

By formula: (O₂^- • 3CO₂) + CO₂ = (O₂^- • 4CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.7	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-0.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 4 Carbon dioxide ) + = ( • 5)

By formula: (O₂^- • 4CO₂) + CO₂ = (O₂^- • 5CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.5 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.4	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 5 Carbon dioxide ) + = ( • 6)

By formula: (O₂^- • 5CO₂) + CO₂ = (O₂^- • 6CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.2 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.0	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.5 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • 6 Carbon dioxide ) + = ( • 7)

By formula: (O₂^- • 6CO₂) + CO₂ = (O₂^- • 7CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.0 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.3	cal/mol*K	PHPMS	Hiraoka and Yamabe, 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-1.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Yamabe, 1992	gas phase; B

( • ) + Carbon dioxide = ( • • )

By formula: (O₂^- • H₂O) + CO₂ = (O₂^- • CO₂ • H₂O)

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.2	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; switching reaction(O2-)2H2O; Arshadi and Kebarle, 1970; M

O₂S⁺ + Carbon dioxide = (O₂S⁺ • )

By formula: O₂S⁺ + CO₂ = (O₂S⁺ • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.6 ± 0.2	kcal/mol	DT	Illies, 1988	gas phase; Δ_rH(0 K)=10.2 kcal/mol; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.5	cal/mol*K	DT	Illies, 1988	gas phase; Δ_rH(0 K)=10.2 kcal/mol; M

O₃S^- + Carbon dioxide = (O₃S^- • )

By formula: O₃S^- + CO₂ = (O₃S^- • CO₂)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.50 ± 0.20	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.7	cal/mol*K	HPMS	Keesee, Lee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	0.30 ± 0.20	kcal/mol	TDAs	Keesee, Lee, et al., 1980	gas phase; B

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, References, Notes

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

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References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes

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Peterson, K.I.; Mark, T.D.; Keesee, R.G.; Castleman, A.W., Thermochemical Properties of Gas - Phase Mixed Clusters: H2O/CO2 with Na+, J. Phys. Chem., 1984, 88, 13, 2880, https://doi.org/10.1021/j150657a042 . [all data]

Perry, Rowe, et al., 1980
Perry, R.A.; Rowe, B.R.; Viggiano, A.A.; Albritton, D.L.; Ferguson, E.E.; Fehsenfeld, F.C., Laboratory Measurements of Stratospheric Sodium Ion Measurements, Geophys. Res. Lett., 1980, 7, 9, 693, https://doi.org/10.1029/GL007i009p00693 . [all data]

Keller and Beyer, 1971, 2
Keller, G.E.; Beyer, R.A., CO2 and O2 Clustering to Sodium Ions, J. Geophys. Res., 1971, 74, 1, 289, https://doi.org/10.1029/JA076i001p00289 . [all data]

Adams and Bohme, 1970
Adams, N.G.; Bohme, D., Flowing Afterglow Studies of Formation and Reactions of Cluster Ions of O₂⁺, O₂^-, and O^-, J. Chem. Phys., 1970, 52, 6, 3133, https://doi.org/10.1063/1.1673449 . [all data]

Roehl, Snodgrass, et al., 1991
Roehl, C.M.; Snodgrass, J.T.; Deakyne, C.A.; Bowers, M.T., Photodissociation of CO3-.H2O: Observation of the O-.H2O + CO2 Product Channel, J. Chem. Phys., 1991, 94, 10, 6546, https://doi.org/10.1063/1.460281 . [all data]

Dotan, Davidson, et al., 1978
Dotan, I.; Davidson, J.A.; Fehsenfeld, F.C.; Albritton, D.L., Reactions of O2+.O2 with CO2, O3 and CH4 and O2+.O3 with H2O and CH4 and their Role in Stratospheric Ion Chemistry, J. Geophys. Res., 1978, 83, C8, 4036, https://doi.org/10.1029/JC083iC08p04036 . [all data]

Conway and Janik, 1970
Conway, D.C.; Janik, G.S., Determination of the Bond Energies for the Series O2 - O2+ through O2 - O10+, J. Chem. Phys., 1970, 53, 5, 1859, https://doi.org/10.1063/1.1674262 . [all data]

Rakshit and Warneck, 1981
Rakshit, A.B.; Warneck, P., Formation and Reactions of O2+.CO2, O2+.H2O and O2+(CO2)2 Ions, Int. J. Mass Spectrom Ion Phys., 1981, 40, 2, 135, https://doi.org/10.1016/0020-7381(81)80037-X . [all data]

Pack and Phelps, 1966
Pack, J.L.; Phelps, A.V., Electron Attachment and Detachment . II. Mixtures of O₂ and CO₂ and of O₂ and H₂O, J. Chem. Phys., 1966, 45, 11, 4316, https://doi.org/10.1063/1.1727491 . [all data]

Vestal and Mauclaire, 1977
Vestal, M.L.; Mauclaire, G.H., Photodissociaton of negative ions formed in CO₂ and CO₂/O₂ Mixtures, J. Chem. Phys., 1977, 67, 3758. [all data]

Conway and Nesbit, 1968
Conway, D.C.; Nesbit, L.E., Stability of O₄^-, J. Chem. Phys., 1968, 48, 1, 509, https://doi.org/10.1063/1.1667956 . [all data]

Fehsenfeld and Ferguson, 1974
Fehsenfeld, F.C.; Ferguson, E.E., Laboratory studies of negative ion reactions with atmospheric trace constituents, J. Chem. Phys., 1974, 61, 3181. [all data]

Arshadi and Kebarle, 1970
Arshadi, M.; Kebarle, P., Hydration of OH^- and O₂^- in the Gas Phase. Comparative Solvation of OH^- by Water and the Hydrogen Halides. Effect of Acidity, J. Phys. Chem., 1970, 74, 7, 1483, https://doi.org/10.1021/j100702a015 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References

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
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
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

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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NIST Chemistry WebBook, SRD 69

Carbon dioxide

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Gas phase thermochemistry data

Gas Phase Heat Capacity (Shomate Equation)

Gas phase ion energetics data

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

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

Mass spectrum (electron ionization)

Spectrum

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