Water

Formula: H₂O
Molecular weight: 18.0153
IUPAC Standard InChI: InChI=1S/H2O/h1H2
IUPAC Standard InChIKey: XLYOFNOQVPJJNP-UHFFFAOYSA-N
CAS Registry Number: 7732-18-5
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:
Other names: Water vapor; Distilled water; Ice; H2O; Dihydrogen oxide; steam; Tritiotope
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Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-57.7978 ± 0.0096	kcal/mol	Review	Cox, Wagman, et al., 1984	CODATA Review value
Δ_fH°_gas	-57.799	kcal/mol	Review	Chase, 1998	Data last reviewed in March, 1979
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	45.1326 ± 0.0024	cal/mol*K	Review	Cox, Wagman, et al., 1984	CODATA Review value
S°_{gas,1 bar}	45.134	cal/mol*K	Review	Chase, 1998	Data last reviewed in March, 1979

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)	500. to 1700.	1700. to 6000.
A	7.192161	10.02970
B	1.633011	2.060720
C	1.623670	-0.358456
D	-0.605755	0.023451
E	0.019632	-2.666740
F	-59.96200	-65.05251
G	53.39309	52.52890
H	-57.79790	-57.79790
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in March, 1979	Data last reviewed in March, 1979

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, References, Notes

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid	-68.3150 ± 0.0096	kcal/mol	Review	Cox, Wagman, et al., 1984	CODATA Review value
Δ_fH°_liquid	-68.315	kcal/mol	Review	Chase, 1998	Data last reviewed in March, 1979
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	16.72 ± 0.007	cal/mol*K	Review	Cox, Wagman, et al., 1984	CODATA Review value
Quantity	Value	Units	Method	Reference	Comment
S°_{liquid,1 bar}	16.72	cal/mol*K	Review	Chase, 1998	Data last reviewed in March, 1979

Liquid Phase Heat Capacity (Shomate Equation)

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Temperature (K)	298. to 500.
A	-48.66300
B	364.0750
C	-763.9610
D	591.4089
E	0.921445
F	-61.31640
G	-116.8060
H	-68.31511
Reference	Chase, 1998
Comment	Data last reviewed in March, 1979

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References, Notes

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director

Quantity	Value	Units	Method	Reference	Comment
T_boil	373.17 ± 0.04	K	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
P_triple	0.0060	atm	N/A	Sato, Watanabe, et al., 1991	Uncertainty assigned by TRC = 1.×10^-7 atm; TRC
Quantity	Value	Units	Method	Reference	Comment
T_c	647. ± 2.	K	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
P_c	217.75	atm	N/A	Sato, Watanabe, et al., 1991	Uncertainty assigned by TRC = 0.05 atm; TRC
P_c	217.72	atm	N/A	Brunner, 1990	Uncertainty assigned by TRC = 0.12 atm; TRC
P_c	217.58	atm	N/A	Morita, Sato, et al., 1989	Uncertainty assigned by TRC = 0.25 atm; based on analysis of their obs. PVT and vapor pressure data some other data from literature; TRC
P_c	217.75	atm	N/A	Aleksandrov, 1986	Uncertainty assigned by TRC = 0.30 atm; TRC
P_c	217.75	atm	N/A	Sifner, 1985	Uncertainty assigned by TRC = 0.0001 atm; TRC
Quantity	Value	Units	Method	Reference	Comment
ρ_c	17.9	mol/l	N/A	Sato, Watanabe, et al., 1991	Uncertainty assigned by TRC = 0.2 mol/l; TRC
ρ_c	17.91	mol/l	N/A	Morita, Sato, et al., 1989	Uncertainty assigned by TRC = 0.083 mol/l; based on analysis of obs. PVT and vapor pressure data; TRC
ρ_c	17.9	mol/l	N/A	Aleksandrov, 1986	Uncertainty assigned by TRC = 0.2 mol/l; TRC
ρ_c	17.9	mol/l	N/A	Sifner, 1985	Uncertainty assigned by TRC = 0.2 mol/l; TRC

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
379. to 573.	3.55388	643.748	-198.043	Liu and Lindsay, 1970	Coefficents calculated by NIST from author's data.
273. to 303.	5.39650	1838.675	-31.737	Bridgeman and Aldrich, 1964	Coefficents calculated by NIST from author's data.
304. to 333.	5.19818	1733.926	-39.485	Bridgeman and Aldrich, 1964	Coefficents calculated by NIST from author's data.
334. to 363.	5.0711	1659.793	-45.854	Bridgeman and Aldrich, 1964	Coefficents calculated by NIST from author's data.
344. to 373.	5.07783	1663.125	-45.622	Bridgeman and Aldrich, 1964	Coefficents calculated by NIST from author's data.
293. to 343.	6.20392	2354.731	7.559	Gubkov, Fermor, et al., 1964	Coefficents calculated by NIST from author's data.
255.9 to 373.	4.6486	1435.264	-64.848	Stull, 1947	Coefficents calculated by NIST from author's data.

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:

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, 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
MS - José A. Martinho Simões

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.

Reactions 1 to 50

+ Water = ( • Water )

By formula: Cl^- + H₂O = (Cl^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15. ± 5.	kcal/mol	AVG	N/A	Average of 11 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19. ± 3.	cal/mol*K	AVG	N/A	Average of 8 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9. ± 4.	kcal/mol	AVG	N/A	Average of 9 values; Individual data points

( • 2 Water ) + Water = ( • 3 Water )

By formula: (H₃O⁺ • 2H₂O) + H₂O = (H₃O⁺ • 3H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.3 ± 0.9	kcal/mol	AVG	N/A	Average of 9 out of 16 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	28. ± 2.	cal/mol*K	AVG	N/A	Average of 6 out of 9 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.4	kcal/mol	FA	Bierbaum, Golde, et al., 1976	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.1	300.	HPMS	Arifov, Pozharov, et al., 1971	gas phase; M
9.2	296.	SAMS	Puckett and Teague, 1971	gas phase; M
8.4	300.	PHPMS	Good, Durden, et al., 1970	gas phase; M
8.3	307.	PHPMS	Good, Durden, et al., 1970, 2	gas phase; M

+ Water = ( • Water )

By formula: CH₃O⁺ + H₂O = (CH₃O⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	28.5	kcal/mol	PHPMS	Meot-Ner (Mautner), 1984	gas phase; switching reaction(H3O+)H2O; Davidson, Sunner J., et al., 1979, Lias, Liebman, et al., 1984; M
Δ_rH°	27.9	kcal/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction((CH3)2O)2H+)(CH3)2O, Entropy change calculated or estimated; Grimsrud and Kebarle, 1973, Yamdagni and Kebarle, 1976, Wolf, Staley, et al., 1977; M
Δ_rH°	28.5	kcal/mol	ICR	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rH°	28.6	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rH°	28.7	kcal/mol	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.9	cal/mol*K	N/A	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rS°	26.9	cal/mol*K	N/A	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rS°	26.8	cal/mol*K	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	20.4	kcal/mol	ICR	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rG°	20.5	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M

+ Water = ( • Water )

By formula: H₃O⁺ + H₂O = (H₃O⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	32. ± 2.	kcal/mol	AVG	N/A	Average of 7 out of 14 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	28. ± 7.	cal/mol*K	AVG	N/A	Average of 5 out of 7 values; Individual data points

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.1	300.	HPMS	Arifov, Pozharov, et al., 1971	gas phase; M

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20. ± 1.	kcal/mol	AVG	N/A	Average of 7 out of 14 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22. ± 4.	cal/mol*K	AVG	N/A	Average of 5 out of 7 values; Individual data points

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.6	300.	HPMS	Arifov, Pozharov, et al., 1971	gas phase; M

( • 3 Water ) + Water = ( • 4 Water )

By formula: (H₃O⁺ • 3H₂O) + H₂O = (H₃O⁺ • 4H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13. ± 4.	kcal/mol	AVG	N/A	Average of 6 out of 9 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24. ± 5.	cal/mol*K	AVG	N/A	Average of 5 out of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	5.5	kcal/mol	FA	Bierbaum, Golde, et al., 1976	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
5.8	293.	ES/HPMS	Klassen, Blades, et al., 1995	gas phase; M
5.4	296.	SAMS	Puckett and Teague, 1971	gas phase; M
5.0	300.	PHPMS	Good, Durden, et al., 1970	gas phase; M
5.0	307.	PHPMS	Good, Durden, et al., 1970, 2	gas phase; M
7.0	300.	HPMS	Arifov, Pozharov, et al., 1971	gas phase; M

+ Water = ( • Water )

By formula: NO₃^- + H₂O = (NO₃^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.60 ± 0.20	kcal/mol	N/A	Lee, Keesee, et al., 1980	gas phase; B,M
Δ_rH°	14.1 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	12.40	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B,M
Δ_rH°	14.8	kcal/mol	ATM	Arnold and Qiu, 1984	gas phase; Entropy change calculated or estimated; M
Δ_rH°	19.2	kcal/mol	FA	Bohringer, Fahey, et al., 1984	gas phase; switching reaction(NO3-)H2O; Lee, Keesee, et al., 1980; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.0	cal/mol*K	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Δ_rS°	25.	cal/mol*K	N/A	Arnold and Qiu, 1984	gas phase; Entropy change calculated or estimated; M
Δ_rS°	21.3	cal/mol*K	FA	Bohringer, Fahey, et al., 1984	gas phase; switching reaction(NO3-)H2O; Lee, Keesee, et al., 1980; M
Δ_rS°	19.1	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.20 ± 0.30	kcal/mol	TDAs	Lee, Keesee, et al., 1980	gas phase; B
Δ_rG°	7.10 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	7.30 ± 0.10	kcal/mol	TDAs	Banic and Iribarne, 1985	gas phase; B
Δ_rG°	6.70	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.8	250.	ATM	Arnold and Qiu, 1984	gas phase; Entropy change calculated or estimated; M
6.8	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; M
7.0	300.	SAMS	Payzant, Cunningham, et al., 1972	gas phase; M

+ Water = ( • Water )

By formula: NO₂^- + H₂O = (NO₂^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16. ± 4.	kcal/mol	AVG	N/A	Average of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Sieck, 1985	gas phase; M
Δ_rS°	20.0	cal/mol*K	FA	Bohringer, Fahey, et al., 1984	gas phase; switching reaction(NO2-)H2O; Lee, Keesee, et al., 1980; M
Δ_rS°	23.8	cal/mol*K	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Δ_rS°	21.	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	8.50 ± 0.20	kcal/mol	TDAs	Sieck, 1985	gas phase; B
Δ_rG°	8.50 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	8.1 ± 5.8	kcal/mol	Endo	Paulson and Dale, 1982	gas phase; B
Δ_rG°	8.10 ± 0.20	kcal/mol	TDAs	Lee, Keesee, et al., 1980	gas phase; B
Δ_rG°	8.00	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
8.0	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; M
8.4	300.	SAMS	Payzant, Cunningham, et al., 1972	gas phase; M

( • 3 Water ) + Water = ( • 4 Water )

By formula: (Na⁺ • 3H₂O) + H₂O = (Na⁺ • 4H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.1 ± 0.9	kcal/mol	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24. ± 3.	cal/mol*K	AVG	N/A	Average of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.1	kcal/mol	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
13.1 (+1.4,-0.)		CID	Dalleska, Tjelta, et al., 1994	gas phase; guided ion beam CID, Na+ (3s0); M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
6.6	293.	ES/HPMS	Klassen, Blades, et al., 1995	gas phase; M
6.4	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M

( • 2 Water ) + Water = ( • 3 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12. ± 2.	kcal/mol	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.3	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	22.4	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	23.2	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	5.0 ± 0.5	kcal/mol	AVG	N/A	Average of 6 values; Individual data points

+ Water = ( • Water )

By formula: I^- + H₂O = (I^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.4 ± 0.7	kcal/mol	AVG	N/A	Average of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	15.3	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	19.3	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	16.3	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	5.5 ± 0.3	kcal/mol	AVG	N/A	Average of 6 values; Individual data points

Free energy of reaction

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

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.90 ± 0.20	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B,M
Δ_rH°	9.50	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	9.50 ± 0.20	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	9.8 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	9.8 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.6	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	20.3	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	19.0	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.0 ± 0.5	kcal/mol	AVG	N/A	Average of 6 values; Individual data points

Free energy of reaction

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

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13. ± 1.	kcal/mol	AVG	N/A	Average of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.4	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	20.5	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	20.8	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.6 ± 1.0	kcal/mol	TDAs	Hiraoka and Mizuse, 1987	gas phase; B
Δ_rG°	6.50	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B
Δ_rG°	6.5 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	6.50	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	6.7	kcal/mol	FA	Fehsenfeld and Ferguson, 1974	gas phase; M

( • Water ) + Water = ( • 2 Water )

By formula: (CH₃O⁺ • H₂O) + H₂O = (CH₃O⁺ • 2H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	21.5	kcal/mol	PHPMS	Meot-Ner (Mautner), 1984	gas phase; M
Δ_rH°	19.9	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)2H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rH°	19.8	kcal/mol	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)2H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	27.0	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1984	gas phase; M
Δ_rS°	26.2	cal/mol*K	N/A	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)2H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rS°	26.3	cal/mol*K	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)2H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	12.1	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)2H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M

( • 2 Water ) + Water = ( • 3 Water )

By formula: (CH₃O⁺ • 2H₂O) + H₂O = (CH₃O⁺ • 3H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.6	kcal/mol	PHPMS	Meot-Ner (Mautner), 1984	gas phase; M
Δ_rH°	16.9	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)3H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rH°	17.0	kcal/mol	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.5	cal/mol*K	PHPMS	Meot-Ner (Mautner), 1984	gas phase; M
Δ_rS°	26.0	cal/mol*K	N/A	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)3H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Δ_rS°	26.0	cal/mol*K	FA	Fehsenfeld, Dotan, et al., 1978	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O; Lias, Liebman, et al., 1984, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.1	kcal/mol	FA	Bohme, Mackay, et al., 1979	gas phase; From thermochemical cycle,switching reaction(H3O+)3H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M

( • 4 Water ) + Water = ( • 5 Water )

By formula: (H₃O⁺ • 4H₂O) + H₂O = (H₃O⁺ • 5H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12. ± 2.	kcal/mol	AVG	N/A	Average of 5 out of 8 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24. ± 4.	cal/mol*K	AVG	N/A	Average of 4 out of 6 values; Individual data points

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.5	293.	ES/HPMS	Klassen, Blades, et al., 1995	gas phase; M

( • Water ) + Water = ( • 2 Water )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19. ± 2.	kcal/mol	AVG	N/A	Average of 8 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.2	cal/mol*K	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rS°	23.	cal/mol*K	N/A	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
19.6 (+1.4,-0.)		CID	Dalleska, Tjelta, et al., 1994	gas phase; guided ion beam CID, Na+ (3s0); M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
10.0	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M

( • 2 Water ) + Water = ( • 3 Water )

By formula: (Na⁺ • 2H₂O) + H₂O = (Na⁺ • 3H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.9	kcal/mol	HPMS	Tang, Lian, et al., 1976	gas phase; M
Δ_rH°	15.8	kcal/mol	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rH°	16.7 ± 1.4	kcal/mol	CIDT	Rodgers and Armentrout, 2000	RCD
Δ_rH°	16.1	kcal/mol	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M
Δ_rH°	16. ± 3.	kcal/mol	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.8	cal/mol*K	HPMS	Tang, Lian, et al., 1976	gas phase; M
Δ_rS°	21.9	cal/mol*K	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rS°	22.0	cal/mol*K	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M
Δ_rS°	23.	cal/mol*K	N/A	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.5	kcal/mol	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
16.8 (+1.4,-0.)		CID	Dalleska, Tjelta, et al., 1994	gas phase; guided ion beam CID, Na+ (3s0); M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.4	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electrospray, Entropy change calculated or estimated; M

( • 3 Water ) + Water = ( • 4 Water )

By formula: (Cl^- • 3H₂O) + H₂O = (Cl^- • 4H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.6 ± 1.0	kcal/mol	TDAs	Hiraoka and Mizuse, 1987	gas phase; B
Δ_rH°	9.70	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	10.6 ± 0.3	kcal/mol	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rH°	10.90 ± 0.70	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B,M
Δ_rH°	11.1 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.7	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	24.8	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	25.8	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.8 ± 1.0	kcal/mol	TDAs	Hiraoka and Mizuse, 1987	gas phase; B
Δ_rG°	3.50	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B
Δ_rG°	3.40	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	4.0 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

( • Water ) + Water = ( • 2 Water )

By formula: (NO₂^- • H₂O) + H₂O = (NO₂^- • 2H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.0 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	12.9 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B,M
Δ_rH°	12.9 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rH°	13.6	kcal/mol	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.4	cal/mol*K	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Δ_rS°	23.7	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.00 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	5.8 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	5.80	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	6.1 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
5.9	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; M
5.8	300.	SAMS	Payzant, Cunningham, et al., 1972	gas phase; M

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.4	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1986	gas phase; Δ_rH?, Entropy change is questionable, appear out of line; M
Δ_rH°	13.7	kcal/mol	PHPMS	Meot-Ner (Mautner), 1984	gas phase; Entropy change calculated or estimated; Δ_rH of 12.4 kcal/mol from plot is too small; M
Δ_rH°	14.7	kcal/mol	PHPMS	Payzant, Cunningham, et al., 1973	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	28.6	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1986	gas phase; Δ_rH?, Entropy change is questionable, appear out of line; M
Δ_rS°	22.0	cal/mol*K	N/A	Meot-Ner (Mautner), 1984	gas phase; Entropy change calculated or estimated; Δ_rH of 12.4 kcal/mol from plot is too small; M
Δ_rS°	21.9	cal/mol*K	PHPMS	Payzant, Cunningham, et al., 1973	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	8.8	kcal/mol	HPMS	Banic and Iribarne, 1985	gas phase; electric fields; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.6	414.	PHPMS	Meot-Ner (Mautner), 1984	gas phase; Entropy change calculated or estimated; Δ_rH of 12.4 kcal/mol from plot is too small; M

C₁₆H₃₄OP₂Ru (solution) + (solution) = C₂₈H₄₃NP₂Ru (solution) + Water (solution)

By formula: C₁₆H₃₄OP₂Ru (solution) + C₁₂H₁₁N (solution) = C₂₈H₄₃NP₂Ru (solution) + H₂O (solution)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.2 ± 0.1	kcal/mol	EqS	Bryndza, Fong, et al., 1987	solvent: Tetrahydrofuran; In a series of reactions involving similar ruthenium complexes, the reaction enthalpy was identified with the reaction Gibbs energy, since the entropy values are expected to be small Bryndza, Fong, et al., 1987. For this reaction, however a van't Hoff plot could be used. Temperature range: 293-328 K; MS
Δ_rH°	4.71	kcal/mol	EqS	Bryndza, Fong, et al., 1987	solvent: Benzene; The reaction enthalpy was identified with the reaction Gibbs energy, since the the entropy is expected to be small Bryndza, Fong, et al., 1987; MS

+ Water = ( • Water )

By formula: C₂H₃O₂^- + H₂O = (C₂H₃O₂^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.40 ± 0.80	kcal/mol	TDAs	Wincel, 2008	gas phase; B
Δ_rH°	15.9 ± 1.0	kcal/mol	N/A	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rH°	16.0 ± 1.0	kcal/mol	N/A	Meot-Ner and Sieck, 1986	gas phase; B,M
Δ_rH°	16.4 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	15.8	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Δ_rS°	22.5	cal/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; ion given as C2H3COO- in paper by error; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	9.0 ± 1.4	kcal/mol	N/A	Wincel, 2008	gas phase; B
Δ_rG°	9.52	kcal/mol	TDAs	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rG°	9.3 ± 1.6	kcal/mol	TDAs	Meot-Ner and Sieck, 1986	gas phase; B
Δ_rG°	9.40 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M

( • 2 Water ) + Water = ( • 3 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	9.30 ± 0.30	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B,M
Δ_rH°	8.5 ± 2.3	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	9.20 ± 0.20	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	9.4 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	9.4 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.4	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	21.0	cal/mol*K	HPMS	Keesee and Castleman, 1980	gas phase; M
Δ_rS°	21.3	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.00	kcal/mol	TDAs	Keesee and Castleman, 1980	gas phase; B
Δ_rG°	3.10 ± 0.80	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	3.3 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

C₂H₅NaO (cr) + 0.5( • 1100 Water ) (solution) = (solution) + 0.5 (solution)

By formula: C₂H₅NaO (cr) + 0.5(H₂O₄S • 1100H₂O) (solution) = C₂H₆O (solution) + 0.5Na₂O₄S (solution)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-28.30 ± 0.91	kcal/mol	RSC	Blanchard, Joly, et al., 1974	solvent: Sulphuric acid aqueous solution; The reaction enthalpy relies on -2.53 kcal/mol for the enthalpy of solution of EtOH(l) and on 9.97±0.04 for the enthalpy of solution of Na2SO4(cr) Blanchard, Joly, et al., 1974. A value of -117.3 ± 1.4 kcal/mol was derived in Blanchard, Joly, et al., 1974 for the enthalpy of formation. However, this value is affected by a calculation error. Also, the authors have not accounted for the acid dilution (this correction could not be made in the present database, due to lack of information). These problems were also noted in the data compilations Tel'noi and Rabinovich, 1980 and Wagman, Evans W.H., et al., 1982, where the values quoted for the enthalpy of formation, which rely on the experimental data reported in Blanchard, Joly, et al., 1974, are -98.0 ± 1.0 kcal/mol and -98.90 kcal/mol, respectively. See also comments in Liebman, Martinho Simões, et al., 1995; MS

+ Water = ( • Water )

By formula: K⁺ + H₂O = (K⁺ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.9	kcal/mol	HPMS	Davidson and Kebarle, 1976	gas phase; M
Δ_rH°	16. ± 3.	kcal/mol	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rH°	19.4 ± 2.5	kcal/mol	MS	Burdett and Hayhurst, 1982	gas phase; flame source, about 1600 K; M
Δ_rH°	17.9	kcal/mol	HPMS	Searles and Kebarle, 1969	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.9	cal/mol*K	HPMS	Davidson and Kebarle, 1976	gas phase; M
Δ_rS°	23.	cal/mol*K	N/A	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rS°	21.3	cal/mol*K	MS	Burdett and Hayhurst, 1982	gas phase; flame source, about 1600 K; M
Δ_rS°	21.6	cal/mol*K	HPMS	Searles and Kebarle, 1969	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.0	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
0.4	840.	MS	Chupka, 1959	gas phase; Knudsen cell, 840+-50K; M

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.60 ± 0.30	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	12.20	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	12.3 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	12.3 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.0	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	22.9	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.2 ± 1.0	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	5.4 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	5.40	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	5.7 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

CN^- + Water = (CN^- • Water )

By formula: CN^- + H₂O = (CN^- • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.70 ± 0.80	kcal/mol	TDAs	Larson, Szulejko, et al., 1988	gas phase; B,M
Δ_rH°	14.6 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988, 2	gas phase; B,B,M,M
Δ_rH°	13.80	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B,M
Δ_rH°	14.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.6	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	18.	cal/mol*K	PHPMS	Larson, Szulejko, et al., 1988	gas phase; M
Δ_rS°	19.6	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Δ_rS°	19.6	cal/mol*K	PHPMS	Meot-ner, 1988, 2	gas phase; M
Δ_rS°	19.8	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.30 ± 0.20	kcal/mol	TDAs	Larson, Szulejko, et al., 1988	gas phase; B
Δ_rG°	8.7 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988	gas phase; B
Δ_rG°	8.7 ± 1.0	kcal/mol	TDAs	Meot-ner, 1988, 2	gas phase; B
Δ_rG°	7.90	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B

( • 2 Water ) + Water = ( • 3 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.40 ± 0.30	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	6.90	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	11.5 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	11.5 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.5	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	24.8	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.7 ± 1.1	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	4.1 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	4.10	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	4.4 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

( • 2 Water ) + Water = ( • 3 Water )

By formula: (NO₂^- • 2H₂O) + H₂O = (NO₂^- • 3H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.5 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	10.4 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B,M
Δ_rH°	10.4 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rH°	11.7	kcal/mol	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.8	cal/mol*K	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Δ_rS°	21.2	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	4.50 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	4.0 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	4.10	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	4.5 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

+ Water = ( • Water )

By formula: Br^- + H₂O = (Br^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.70	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	11.70 ± 0.40	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	12.60	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Δ_rH°	12.7	kcal/mol	HPMS	Caldwell, Masucci, et al., 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	14.7	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	18.4	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Δ_rS°	19.8	cal/mol*K	MS	Burdett and Hayhurst, 1982	gas phase; FLAME SOURCE, 1600 K; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.30 ± 0.80	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	7.0 ± 2.8	kcal/mol	TDAs	Burdett and Hayhurst, 1982	gas phase; B
Δ_rG°	7.0 ± 2.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B

CH₂N⁺ + Water = (CH₂N⁺ • Water )

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

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	27.4	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rH°	29.6	kcal/mol	ICR	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	24.2	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1989	gas phase; n; M
Δ_rS°	28.8	cal/mol*K	N/A	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
21.0	300.	ICR	Berman and Beauchamp, 1980	gas phase; From thermochemical cycle,switching reaction(H3O+)H2O, Entropy change calculated or estimated; Lias, Liebman, et al., 1984, Fehsenfeld, Dotan, et al., 1978, Meot-Ner (Mautner), 1992; M

+ Water = ( • Water )

By formula: HO^- + H₂O = (HO^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	27.0 ± 0.9	kcal/mol	AVG	N/A	Average of 3 out of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	28.1	cal/mol*K	PHPMS	Paul and Kebarle, 1990	gas phase; M
Δ_rS°	21.8	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1986	gas phase; deuterated; M
Δ_rS°	20.8	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Δ_rS°	19.1	cal/mol*K	PHPMS	Arshadi and Kebarle, 1970	gas phase; deuterated; M

HO^- + Water = (HO^- • Water )

By formula: HO^- + H₂O = (HO^- • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	28. ± 7.	kcal/mol	AVG	N/A	Average of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	19.2 ± 1.0	kcal/mol	TDAs	Paul and Kebarle, 1990	gas phase; B
Δ_rG°	20.1 ± 1.6	kcal/mol	TDEq	Meot-Ner and Sieck, 1986	gas phase; B
Δ_rG°	20.0 ± 1.4	kcal/mol	TDAs	Meot-Ner (Mautner) and Speller, 1986	gas phase; B
Δ_rG°	18.60	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	19.20 ± 0.50	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; Stated electron affinity is the Vertical Detachment Energy; B,M
Δ_rH°	16.6 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	16.6 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.2	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	18.7	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	12.5 ± 1.6	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; Stated electron affinity is the Vertical Detachment Energy; B
Δ_rG°	11.0 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	11.00	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B

( • 2 Water ) + Water = ( • 3 Water )

By formula: (C₂H₃O₂^- • 2H₂O) + H₂O = (C₂H₃O₂^- • 3H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.8 ± 1.0	kcal/mol	N/A	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rH°	12.2 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	11.8	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	N/A	Meot-ner, 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	5.84	kcal/mol	TDAs	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rG°	5.20 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	5.9	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; Entropy change calculated or estimated; M

( • 3 Water ) + Water = ( • 4 Water )

By formula: (Br^- • 3H₂O) + H₂O = (Br^- • 4H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.00 ± 0.20	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	6.2 ± 2.3	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	10.9 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.2	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	26.8	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	3.10 ± 0.70	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	2.90	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B
Δ_rG°	3.3 ± 2.0	kcal/mol	TDAs	Kebarle, Arshadi, et al., 1968	gas phase; B,M

O₃P^- + Water = (O₃P^- • Water )

By formula: O₃P^- + H₂O = (O₃P^- • H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.90 ± 0.30	kcal/mol	TDAs	Keesee and Castleman Jr., 1989	gas phase; Not (HO)2PO2-. See also Blades, Ho, et al., 1996 : (HO)2PO2- -> PO3- + HOH, Eact ca. 55 kcal/mol.; B,M,M
Δ_rH°	12.6	kcal/mol	ES/HPMS	Blades, Ho, et al., 1996, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.8	cal/mol*K	ES/HPMS	Blades, Ho, et al., 1996, 2	gas phase; M
Δ_rS°	22.2	cal/mol*K	HPMS	Keesee and Castleman Jr., 1989	gas phase; M
Δ_rS°	20.8	cal/mol*K	HPMS	Keesee and Castleman Jr., 1989	gas phase; deuterated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.3 ± 1.2	kcal/mol	TDAs	Keesee and Castleman Jr., 1989	gas phase; Not (HO)2PO2-. See also Blades, Ho, et al., 1996 : (HO)2PO2- -> PO3- + HOH, Eact ca. 55 kcal/mol.; B
Δ_rG°	6.4	kcal/mol	ES/HPMS	Blades, Ho, et al., 1996, 2	gas phase; M

+ Water = ( • Water )

By formula: Na⁺ + H₂O = (Na⁺ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	24.0	kcal/mol	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rH°	21.0 ± 1.4	kcal/mol	CIDC	Amicangelo and Armentrout, 2001	Anchor NH3=24.41; RCD
Δ_rH°	19.6 ± 1.4	kcal/mol	CIDC	Amicangelo and Armentrout, 2001	Anchor NH3=24.41; RCD
Δ_rH°	22.7 ± 1.9	kcal/mol	CIDT	Rodgers and Armentrout, 2000	RCD
Δ_rH°	26.5	kcal/mol	MS	Burdett and Hayhurst, 1982	gas phase; flame source, 1600 K; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.5	cal/mol*K	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rS°	22.	cal/mol*K	MS	Burdett and Hayhurst, 1982	gas phase; flame source, 1600 K; M

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
22.6 (+1.8,-0.)		CID	Dalleska, Tjelta, et al., 1994	gas phase; guided ion beam CID, Na+ (3s0); M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
15.7	298.	IMRE	McMahon and Ohanessian, 2000	Anchor alanine=39.89; RCD

( • 2 Water ) + Water = ( • 3 Water )

By formula: (K⁺ • 2H₂O) + H₂O = (K⁺ • 3H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	13.0	kcal/mol	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M
Δ_rH°	14. ± 3.	kcal/mol	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rH°	13.2	kcal/mol	HPMS	Searles and Kebarle, 1969	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.5	cal/mol*K	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M
Δ_rS°	23.	cal/mol*K	N/A	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rS°	23.0	cal/mol*K	HPMS	Searles and Kebarle, 1969	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	6.3	kcal/mol	ES/HPMS	Blades, Klassen, et al., 1996	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
6.6	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M

( • Water ) + Water = ( • 2 Water )

By formula: (C₂H₃O₂^- • H₂O) + H₂O = (C₂H₃O₂^- • 2H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.9 ± 1.0	kcal/mol	N/A	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rH°	13.8 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	12.8	kcal/mol	PHPMS	Meot-ner, 1988	gas phase; M
Δ_rH°	12.9	kcal/mol	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.1	cal/mol*K	PHPMS	Meot-ner, 1988	gas phase; M
Δ_rS°	20.5	cal/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	7.00	kcal/mol	TDAs	Meot-ner, Elmore, et al., 1999	gas phase; B
Δ_rG°	6.80 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M

( • 6 Water ) + Water = ( • 7 Water )

By formula: (Cl^- • 6H₂O) + H₂O = (Cl^- • 7H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	8.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Mizuse, 1987	gas phase; Estimated entropy; single temperature measurement; B
Δ_rH°	6.90	kcal/mol	N/A	Markovich, Pollack, et al., 1994	gas phase; For photodissociation plus electron loss. Affinity is difference from lower solvated ion.; B
Δ_rH°	8.1	kcal/mol	PHPMS	Hiraoka, Mizuse, 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, Mizuse, et al., 1988	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	2.1 ± 1.0	kcal/mol	TDAs	Hiraoka and Mizuse, 1987	gas phase; Estimated entropy; single temperature measurement; B

+ Water = ( • Water )

By formula: Rb⁺ + H₂O = (Rb⁺ • H₂O)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.9	kcal/mol	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rH°	16. ± 3.	kcal/mol	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rH°	16.0	kcal/mol	MS	Burdett and Hayhurst, 1982	gas phase; flame source, about 1600 K; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	HPMS	Dzidic and Kebarle, 1970	gas phase; M
Δ_rS°	23.	cal/mol*K	N/A	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M
Δ_rS°	20.1	cal/mol*K	MS	Burdett and Hayhurst, 1982	gas phase; flame source, about 1600 K; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
9.4	300.	HPMS	Blades, Jayaweera, et al., 1990	gas phase; electospray, Entropy change calculated or estimated; M

( • Water ) + Water = ( • 2 Water )

By formula: (NO₃^- • H₂O) + H₂O = (NO₃^- • 2H₂O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.2 ± 1.5	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B
Δ_rH°	14.3	kcal/mol	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	30.3	cal/mol*K	HPMS	Lee, Keesee, et al., 1980	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	5.20 ± 0.30	kcal/mol	TDAs	Blades, Klassen, et al., 1995	gas phase; T: 293 K. ΔSaff approx. 24 cal/mol-K; B,M
Δ_rG°	5.20 ± 0.10	kcal/mol	TDAs	Banic and Iribarne, 1985	gas phase; B

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
5.2	301.	HPMS	Banic and Iribarne, 1985	gas phase; electric fields; M
5.0	296.	FA	Fehsenfeld and Ferguson, 1974	gas phase; M

C₄H₆N⁺ + Water = (C₄H₆N⁺ • Water )

By formula: C₄H₆N⁺ + H₂O = (C₄H₆N⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.0	kcal/mol	PHPMS	Nicol, Sunner, et al., 1988	gas phase; M
Δ_rH°	13.8	kcal/mol	PHPMS	Hiraoka, Takimoto, et al., 1987	gas phase; M
Δ_rH°	16.	kcal/mol	PHPMS	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.3	cal/mol*K	PHPMS	Nicol, Sunner, et al., 1988	gas phase; M
Δ_rS°	22.0	cal/mol*K	PHPMS	Hiraoka, Takimoto, et al., 1987	gas phase; M
Δ_rS°	32.	cal/mol*K	N/A	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.9	344.	PHPMS	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M

C₂H₂F₃O₂⁺ + Water = (C₂H₂F₃O₂⁺ • Water )

By formula: C₂H₂F₃O₂⁺ + H₂O = (C₂H₂F₃O₂⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	28.3	kcal/mol	ICR	Larson and McMahon, 1982	gas phase; From thermochemical cycle(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.3	cal/mol*K	N/A	Larson and McMahon, 1982	gas phase; From thermochemical cycle(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
21.4	309.	ICR	Larson and McMahon, 1982	gas phase; From thermochemical cycle(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

C₄H₅O⁺ + Water = (C₄H₅O⁺ • Water )

By formula: C₄H₅O⁺ + H₂O = (C₄H₅O⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	10.4	kcal/mol	PHPMS	Nicol, Sunner, et al., 1988	gas phase; M
Δ_rH°	10.2	kcal/mol	PHPMS	Hiraoka, Takimoto, et al., 1987	gas phase; M
Δ_rH°	16.	kcal/mol	PHPMS	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.	cal/mol*K	PHPMS	Nicol, Sunner, et al., 1988	gas phase; M
Δ_rS°	19.7	cal/mol*K	PHPMS	Hiraoka, Takimoto, et al., 1987	gas phase; M
Δ_rS°	32.	cal/mol*K	N/A	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
4.2	382.	PHPMS	Meot-Ner (Mautner), Ross, et al., 1985	gas phase; Entropy change calculated or estimated, Δ_rH<; M

( • 2 Water ) + Water = ( • 3 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	15.30 ± 0.40	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B,M
Δ_rH°	13.7 ± 1.0	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rH°	13.7 ± 1.0	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B,M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.9	cal/mol*K	PHPMS	Hiraoka, Mizuse, et al., 1988	gas phase; M
Δ_rS°	20.4	cal/mol*K	HPMS	Arshadi, Yamdagni, et al., 1970	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	8.4 ± 1.3	kcal/mol	TDAs	Hiraoka, Mizuse, et al., 1988	gas phase; B
Δ_rG°	7.6 ± 1.4	kcal/mol	TDAs	Payzant, Yamdagni, et al., 1971	gas phase; B
Δ_rG°	7.60	kcal/mol	TDAs	Arshadi, Yamdagni, et al., 1970	gas phase; B

( • Water ) + Water = ( • 2 Water )

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

Bond type: Hydrogen bond (negative ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	17.6	kcal/mol	PHPMS	Meot-Ner (Mautner) and Speller, 1986	gas phase; deuterated; M
Δ_rH°	18.	kcal/mol	CID	Hierl and Paulson, 1984	gas phase; M
Δ_rH°	17.9	kcal/mol	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Δ_rH°	16.4	kcal/mol	PHPMS	Arshadi and Kebarle, 1970	gas phase; deuterated; M
Δ_rH°	23.	kcal/mol	CID	DePaz, Giardini, et al., 1970	gas phase; deuterated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.4	cal/mol*K	PHPMS	Meot-Ner (Mautner) and Speller, 1986	gas phase; deuterated; M
Δ_rS°	21.2	cal/mol*K	HPMS	Payzant, Yamdagni, et al., 1971	gas phase; M
Δ_rS°	19.3	cal/mol*K	PHPMS	Arshadi and Kebarle, 1970	gas phase; deuterated; M

C₂H₄F₃O⁺ + Water = (C₂H₄F₃O⁺ • Water )

By formula: C₂H₄F₃O⁺ + H₂O = (C₂H₄F₃O⁺ • H₂O)

Bond type: Hydrogen bond (positive ion to hydride)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	30.5	kcal/mol	ICR	Larson and McMahon, 1982	gas phase; switching reaction(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.8	cal/mol*K	N/A	Larson and McMahon, 1982	gas phase; switching reaction(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
23.4	309.	ICR	Larson and McMahon, 1982	gas phase; switching reaction(H3O+)H2O, Entropy change calculated or estimated; Cunningham, Payzant, et al., 1972, Lias, Liebman, et al., 1984, Keesee and Castleman, 1986; M

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Notes

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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]

Keesee and Castleman, 1986
Keesee, R.G.; Castleman, A.W., Jr., Thermochemical data on Ggs-phase ion-molecule association and clustering reactions, J. Phys. Chem. Ref. Data, 1986, 15, 1011. [all data]

Hierl and Paulson, 1984
Hierl, P.M.; Paulson, J.F., Translational energy dependence of cross sections for reactions of OH^- (H₂O)n with CO₂ and SO₂, J. Chem. Phys., 1984, 80, 4890. [all data]

DePaz, Giardini, et al., 1970
DePaz, M.; Giardini, A.G.; Friedman, L., Tandem-Mass-Spectrometer Study of Solvated Derivatives of OD-. Total Hydration Energy of the Proton, J. Chem. Phys., 1970, 52, 2, 687, https://doi.org/10.1063/1.1673041 . [all data]

Notes

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Symbols used in this document:

P_c	Critical pressure
P_triple	Triple point pressure
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
S°_liquid	Entropy of liquid at standard conditions
S°_{liquid,1 bar}	Entropy of liquid at standard conditions (1 bar)
T	Temperature
T_boil	Boiling point
T_c	Critical temperature
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid 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
ρ_c	Critical density

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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