Argon

Formula: Ar
Molecular weight: 39.948
IUPAC Standard InChI: InChI=1S/Ar
IUPAC Standard InChIKey: XKRFYHLGVUSROY-UHFFFAOYSA-N
CAS Registry Number: 7440-37-1
Chemical structure:
This structure is also available as a 2d Mol file
Other names: Ar; UN 1006; UN 1951; argon atom
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Information on this page:
Other data available:
- Reaction thermochemistry data: reactions 51 to 100, reactions 101 to 102
- Fluid Properties
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Gas phase thermochemistry data

Go To: Top, Phase change data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References, Notes

Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	37.0091 ± 0.0007	cal/mol*K	Review	Cox, Wagman, et al., 1984	CODATA Review value
S°_{gas,1 bar}	37.008	cal/mol*K	Review	Chase, 1998	Data last reviewed in March, 1982

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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View table.

Temperature (K)	298. to 6000.
A	4.967974
B	6.754087×10^-8
C	-3.499499×10^-8
D	2.610254×10^-9
E	-8.750885×10^-9
F	-1.481203
G	43.02079
H	0.000000
Reference	Chase, 1998
Comment	Data last reviewed in March, 1982

Phase change data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), 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	87.5	K	N/A	Streng, 1971	Uncertainty assigned by TRC = 0.3 K; TRC
T_boil	87.28	K	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.02 K; TRC
Quantity	Value	Units	Method	Reference	Comment
T_fus	83.8	K	N/A	Van't Zelfde, Omar, et al., 1968	Uncertainty assigned by TRC = 0.3 K; TRC
Quantity	Value	Units	Method	Reference	Comment
T_triple	87.78	K	N/A	Angus, Armstrong, et al., 1972	Uncertainty assigned by TRC = 0.05 K; TRC
T_triple	83.8	K	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.05 K; TRC
T_triple	83.8	K	N/A	Ziegler, Mullins, et al., 1962	Uncertainty assigned by TRC = 0.05 K; TRC
T_triple	83.78	K	N/A	Clark, Din, et al., 1951	Uncertainty assigned by TRC = 0.04 K; TRC
T_triple	83.78	K	N/A	Clusius and Weigand, 1940	Uncertainty assigned by TRC = 0.2 K; See property X for dP/dT at triple point; TRC
Quantity	Value	Units	Method	Reference	Comment
P_triple	0.680	atm	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.0001 atm; TRC
P_triple	0.680	atm	N/A	Ziegler, Mullins, et al., 1962	Uncertainty assigned by TRC = 0.0001 atm; TRC
P_triple	0.6785	atm	N/A	Clark, Din, et al., 1951	Uncertainty assigned by TRC = 0.0007 atm; TRC
Quantity	Value	Units	Method	Reference	Comment
T_c	150.86	K	N/A	Angus, Armstrong, et al., 1972	Uncertainty assigned by TRC = 0.1 K; TRC
T_c	150.86	K	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.1 K; TRC
T_c	150.65	K	N/A	McCain and Ziegler, 1967	Uncertainty assigned by TRC = 0.03 K; TRC
Quantity	Value	Units	Method	Reference	Comment
P_c	4.8339	atm	N/A	Angus, Armstrong, et al., 1972	Uncertainty assigned by TRC = 0.002 atm; TRC
P_c	48.3400	atm	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.09998 atm; TRC
P_c	47.9200	atm	N/A	McCain and Ziegler, 1967	Uncertainty assigned by TRC = 0.0700 atm; TRC
Quantity	Value	Units	Method	Reference	Comment
ρ_c	13.41	mol/l	N/A	Angus, Armstrong, et al., 1972	Uncertainty assigned by TRC = 0.005 mol/l; TRC
ρ_c	8.4029	mol/l	N/A	Gosman, McCarty, et al., 1969	Uncertainty assigned by TRC = 0.008 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
114.40 to 150.31	4.46332	481.012	22.156	McCain and Ziegler, 1967	Coefficents calculated by NIST from author's data.
83.78 to 150.72	3.28984	215.24	-22.233	Drii and Rabinovich, 1966	Coefficents calculated by NIST from author's data.
129.33 to 147.40	4.96600	658.982	49.819	van Itterbeek, Verbeke, et al., 1963	Coefficents calculated by NIST from author's data.
90.94 to 101.48	3.72908	302.683	-6.083	Clark, Din, et al., 1951, 2	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, Phase change data, Henry's Law data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References, Notes

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

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Reactions 1 to 50

+ Argon = ( • Argon )

By formula: Li⁺ + Ar = (Li⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7. ± 1.	kcal/mol	AVG	N/A	Average of 4 out of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	7.	cal/mol*K	DT	McKnight and Sawina, 1973	gas phase; Δ_rS approximate; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
1.4	294.	IMob	Cassidy and Elford, 1985	gas phase; M
1.9	319.	DT	Keller, Beyer, et al., 1973	gas phase; LOW E/N; M
2.6	215.	DT	McKnight and Sawina, 1973	gas phase; Δ_rS approximate; M

Ar⁺ + Argon = (Ar⁺ • Argon )

By formula: Ar⁺ + Ar = (Ar⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20. ± 20.	kcal/mol	AVG	N/A	Average of 5 out of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	12.8	cal/mol*K	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)Ar; Turner and Conway, 1979, Liu and Conway, 1975; M

+ Argon = ( • Argon )

By formula: K⁺ + Ar = (K⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.8 ± 0.7	kcal/mol	AVG	N/A	Average of 9 values; Individual data points

+ Argon = ( • Argon )

By formula: N₂⁺ + Ar = (N₂⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	26.8	kcal/mol	PD/KERD	Kim and Bowers, 1990	gas phase; switching reaction(N2+)N2; Hiraoka and Nakajima, 1988; M
Δ_rH°	25.4	kcal/mol	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)N2; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.5	cal/mol*K	PD/KERD	Kim and Bowers, 1990	gas phase; switching reaction(N2+)N2; Hiraoka and Nakajima, 1988; M
Δ_rS°	13.7	cal/mol*K	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)N2; M

+ Argon = ( • Argon )

By formula: Cs⁺ + Ar = (Cs⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.95	kcal/mol	IMob	Gatland, 1984	gas phase; M
Δ_rH°	1.46	kcal/mol	SCATTERING	Gislason, 1984	gas phase; M
Δ_rH°	1.96	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	2.28	kcal/mol	IMob	Takebe, 1983	gas phase; M
Δ_rH°	2.3	kcal/mol	IMob	Takebe, 1983	gas phase; values from this reference are consistently too high; M

+ Argon = ( • Argon )

By formula: Cr⁺ + Ar = (Cr⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.9 ± 0.4	kcal/mol	SIDT	Kemper, Hsu, et al., 1991	gas phase; Δ_rH(0 K) = 6.55 kcal/mol, Δ_rS(100 K) = 14.4 cal/mol*K; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	15.8	cal/mol*K	SIDT	Kemper, Hsu, et al., 1991	gas phase; Δ_rH(0 K) = 6.55 kcal/mol, Δ_rS(100 K) = 14.4 cal/mol*K; M

+ Argon = ( • Argon )

By formula: Na⁺ + Ar = (Na⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.7 ± 2.1	kcal/mol	CIDT	Armentrout and Rodgers, 2000	RCD
Δ_rH°	3.70	kcal/mol	SCATTERING	Gislason, 1984	gas phase; M
Δ_rH°	4.39	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	4.4	kcal/mol	DT	McKnight and Sawina, 1973	gas phase; M
Δ_rH°	4.87	kcal/mol	IMob	Takebe, 1983	gas phase; M

H₃⁺ + Argon = (H₃⁺ • Argon )

By formula: H₃⁺ + Ar = (H₃⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Δ_rH°	7.5 ± 0.8	kcal/mol	SIFT	Bedford and Smith, 1990	gas phase; switching reaction(H3+)H2, Hiraoka and Mori, 1989; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

Xe⁺ + Argon = (Xe⁺ • Argon )

By formula: Xe⁺ + Ar = (Xe⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.1	kcal/mol	PI	Dehmer and Pratt, 1982	gas phase; M
Δ_rH°	6.0	kcal/mol	SIFT	Jones, Lister, et al., 1980	gas phase; M
Δ_rH°	3.2	kcal/mol	PI	Ng, Tiedemann, et al., 1977	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.4	cal/mol*K	SIFT	Jones, Lister, et al., 1980	gas phase; M

(Ar⁺ • 2 Argon ) + Argon = (Ar⁺ • 3 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.9 ± 0.3	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
2.0	77.	PHPMS	Teng and Conway, 1973	gas phase; M

( • 7 Argon ) + Argon = ( • 8 Argon )

By formula: (N₂⁺ • 7Ar) + Ar = (N₂⁺ • 8Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.53	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	N/A	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M

( • 8 Argon ) + Argon = ( • 9 Argon )

By formula: (N₂⁺ • 8Ar) + Ar = (N₂⁺ • 9Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.52	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	N/A	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M

+ Argon = ArF^-

By formula: F^- + Ar = ArF^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.00	kcal/mol	TDAs	Wada, Kikkawa, et al., 2007	gas phase; Entropy estimated; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-3.96	kcal/mol	TDAs	Wada, Kikkawa, et al., 2007	gas phase; Entropy estimated; B

+ Argon = ( • Argon )

By formula: Rb⁺ + Ar = (Rb⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.03	kcal/mol	IMob	Gatland, 1984	gas phase; M
Δ_rH°	1.98	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	2.84	kcal/mol	IMob	Takebe, 1983	gas phase; M

(O^- • 10 Argon ) + Argon = (O^- • 11 Argon )

By formula: (O^- • 10Ar) + Ar = (O^- • 11Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 11 Argon ) + Argon = (O^- • 12 Argon )

By formula: (O^- • 11Ar) + Ar = (O^- • 12Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.8 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 12 Argon ) + Argon = (O^- • 13 Argon )

By formula: (O^- • 12Ar) + Ar = (O^- • 13Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 13 Argon ) + Argon = (O^- • 14 Argon )

By formula: (O^- • 13Ar) + Ar = (O^- • 14Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 14 Argon ) + Argon = (O^- • 15 Argon )

By formula: (O^- • 14Ar) + Ar = (O^- • 15Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 15 Argon ) + Argon = (O^- • 16 Argon )

By formula: (O^- • 15Ar) + Ar = (O^- • 16Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 16 Argon ) + Argon = (O^- • 17 Argon )

By formula: (O^- • 16Ar) + Ar = (O^- • 17Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 17 Argon ) + Argon = (O^- • 18 Argon )

By formula: (O^- • 17Ar) + Ar = (O^- • 18Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 18 Argon ) + Argon = (O^- • 19 Argon )

By formula: (O^- • 18Ar) + Ar = (O^- • 19Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 19 Argon ) + Argon = (O^- • 20 Argon )

By formula: (O^- • 19Ar) + Ar = (O^- • 20Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 20 Argon ) + Argon = (O^- • 21 Argon )

By formula: (O^- • 20Ar) + Ar = (O^- • 21Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 21 Argon ) + Argon = (O^- • 22 Argon )

By formula: (O^- • 21Ar) + Ar = (O^- • 22Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 22 Argon ) + Argon = (O^- • 23 Argon )

By formula: (O^- • 22Ar) + Ar = (O^- • 23Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 23 Argon ) + Argon = (O^- • 24 Argon )

By formula: (O^- • 23Ar) + Ar = (O^- • 24Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 24 Argon ) + Argon = (O^- • 25 Argon )

By formula: (O^- • 24Ar) + Ar = (O^- • 25Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 25 Argon ) + Argon = (O^- • 26 Argon )

By formula: (O^- • 25Ar) + Ar = (O^- • 26Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 9 Argon ) + Argon = (O^- • 10 Argon )

By formula: (O^- • 9Ar) + Ar = (O^- • 10Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.7 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 2 Argon ) + Argon = (O^- • 3 Argon )

By formula: (O^- • 2Ar) + Ar = (O^- • 3Ar)

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

(O^- • 3 Argon ) + Argon = (O^- • 4 Argon )

By formula: (O^- • 3Ar) + Ar = (O^- • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 4 Argon ) + Argon = (O^- • 5 Argon )

By formula: (O^- • 4Ar) + Ar = (O^- • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 5 Argon ) + Argon = (O^- • 6 Argon )

By formula: (O^- • 5Ar) + Ar = (O^- • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 6 Argon ) + Argon = (O^- • 7 Argon )

By formula: (O^- • 6Ar) + Ar = (O^- • 7Ar)

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

(O^- • 7 Argon ) + Argon = (O^- • 8 Argon )

By formula: (O^- • 7Ar) + Ar = (O^- • 8Ar)

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

(O^- • 8 Argon ) + Argon = (O^- • 9 Argon )

By formula: (O^- • 8Ar) + Ar = (O^- • 9Ar)

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

(O^- • Argon ) + Argon = (O^- • 2 Argon )

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

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

(Ar⁺ • Argon ) + Argon = (Ar⁺ • 2 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.06 ± 0.08	kcal/mol	PHPMS	Turner and Conway, 1979	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Turner and Conway, 1979	gas phase; M

( • Argon ) + Argon = ( • 2 Argon )

By formula: (N₂⁺ • Ar) + Ar = (N₂⁺ • 2Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.8	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Δ_rH>; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Δ_rH>; M

O^- + Argon = (O^- • Argon )

By formula: O^- + Ar = (O^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(Ar⁺ • 10 Argon ) + Argon = (Ar⁺ • 11 Argon )

By formula: (Ar⁺ • 10Ar) + Ar = (Ar⁺ • 11Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 9 Argon ) + Argon = (Ar⁺ • 10 Argon )

By formula: (Ar⁺ • 9Ar) + Ar = (Ar⁺ • 10Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.55 ± 0.20	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(D₃⁺ • 2 Argon ) + Argon = (D₃⁺ • 3 Argon )

By formula: (D₃⁺ • 2Ar) + Ar = (D₃⁺ • 3Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.4 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 3 Argon ) + Argon = (D₃⁺ • 4 Argon )

By formula: (D₃⁺ • 3Ar) + Ar = (D₃⁺ • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.4 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.6	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 4 Argon ) + Argon = (D₃⁺ • 5 Argon )

By formula: (D₃⁺ • 4Ar) + Ar = (D₃⁺ • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.3 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 5 Argon ) + Argon = (D₃⁺ • 6 Argon )

By formula: (D₃⁺ • 5Ar) + Ar = (D₃⁺ • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.2 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 6 Argon ) + Argon = (D₃⁺ • 7 Argon )

By formula: (D₃⁺ • 6Ar) + Ar = (D₃⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.2	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(Ar⁺ • 3 Argon ) + Argon = (Ar⁺ • 4 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.9	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

Henry's Law data

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

Data compiled by: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

k°_H (mol/(kg*bar))	d(ln(k_H))/d(1/T) (K)	Method	Reference
0.0014	1500.	L	N/A
0.0014	1100.	M	N/A

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law 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
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	15.759 ± 0.001	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	88.24	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	82.77	kcal/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
15.763	PIPECO	Weitzel, Mahnert, et al., 1994	LL
15.75962	EVAL	Lide, 1992	LL
15.82	EI	Wetzel, Baiocchi, et al., 1987	LBLHLM
15.760	S	Kelly, 1987	LBLHLM
15.759	PE	Kimura, Katsumata, et al., 1981	LLK
15.88	EI	Clare and Sowerby, 1981	LLK
15.7	EI	Freiser, 1980	LLK
15.75962 ± 0.00001	S	Minnhagen, 1973	LLK
15.753 ± 0.002	TE	Spohr, Guyon, et al., 1971	LLK
15.75962 ± 0.00001	S	Yoshino, 1970	RDSH
15.759	S	Yoshino, 1969	RDSH
15.713 ± 0.003	CI	Hotop and Niehaus, 1969	RDSH
15.757 ± 0.005	PE	Collin and Natalis, 1968	RDSH
15.74 ± 0.05	EI	Gallegos and Klaver, 1967	RDSH
15.78 ± 0.03	EI	Winters, Collins, et al., 1966	RDSH
15.79	PE	Al-Joboury and Turner, 1963	RDSH

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes

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

Ar⁺ + Argon = (Ar⁺ • Argon )

By formula: Ar⁺ + Ar = (Ar⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	20. ± 20.	kcal/mol	AVG	N/A	Average of 5 out of 7 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	12.8	cal/mol*K	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)Ar; Turner and Conway, 1979, Liu and Conway, 1975; M

(Ar⁺ • Argon ) + Argon = (Ar⁺ • 2 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.06 ± 0.08	kcal/mol	PHPMS	Turner and Conway, 1979	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.3	cal/mol*K	PHPMS	Turner and Conway, 1979	gas phase; M

(Ar⁺ • 2 Argon ) + Argon = (Ar⁺ • 3 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.9 ± 0.3	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
2.0	77.	PHPMS	Teng and Conway, 1973	gas phase; M

(Ar⁺ • 3 Argon ) + Argon = (Ar⁺ • 4 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.9	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 4 Argon ) + Argon = (Ar⁺ • 5 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 5 Argon ) + Argon = (Ar⁺ • 6 Argon )

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

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.0	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 6 Argon ) + Argon = (Ar⁺ • 7 Argon )

By formula: (Ar⁺ • 6Ar) + Ar = (Ar⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 7 Argon ) + Argon = (Ar⁺ • 8 Argon )

By formula: (Ar⁺ • 7Ar) + Ar = (Ar⁺ • 8Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 8 Argon ) + Argon = (Ar⁺ • 9 Argon )

By formula: (Ar⁺ • 8Ar) + Ar = (Ar⁺ • 9Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 9 Argon ) + Argon = (Ar⁺ • 10 Argon )

By formula: (Ar⁺ • 9Ar) + Ar = (Ar⁺ • 10Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.55 ± 0.20	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

(Ar⁺ • 10 Argon ) + Argon = (Ar⁺ • 11 Argon )

By formula: (Ar⁺ • 10Ar) + Ar = (Ar⁺ • 11Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989, 2	gas phase; M

ArNO^- + 2 Argon = Ar₂NO^-

By formula: ArNO^- + 2Ar = Ar₂NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.50	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₂NO^- + 3 Argon = Ar₃NO^-

By formula: Ar₂NO^- + 3Ar = Ar₃NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.30	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₃NO^- + 4 Argon = Ar₄NO^-

By formula: Ar₃NO^- + 4Ar = Ar₄NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.30	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₄NO^- + 5 Argon = Ar₅NO^-

By formula: Ar₄NO^- + 5Ar = Ar₅NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.30	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₅NO^- + 6 Argon = Ar₆NO^-

By formula: Ar₅NO^- + 6Ar = Ar₆NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.20	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₆NO^- + 7 Argon = Ar₇NO^-

By formula: Ar₆NO^- + 7Ar = Ar₇NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.90	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₇NO^- + 8 Argon = Ar₈NO^-

By formula: Ar₇NO^- + 8Ar = Ar₈NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.90	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₈NO^- + 9 Argon = Ar₉NO^-

By formula: Ar₈NO^- + 9Ar = Ar₉NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.70	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₉NO^- + 10 Argon = Ar₁₀NO^-

By formula: Ar₉NO^- + 10Ar = Ar₁₀NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.70	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₁₀NO^- + 11 Argon = Ar₁₁NO^-

By formula: Ar₁₀NO^- + 11Ar = Ar₁₁NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.60	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₁₁NO^- + 12 Argon = Ar₁₂NO^-

By formula: Ar₁₁NO^- + 12Ar = Ar₁₂NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.70	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₁₂NO^- + 13 Argon = Ar₁₃NO^-

By formula: Ar₁₂NO^- + 13Ar = Ar₁₃NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.30	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

Ar₁₃NO^- + 14 Argon = Ar₁₄NO^-

By formula: Ar₁₃NO^- + 14Ar = Ar₁₄NO^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.20	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B

+ Argon = ( • Argon )

By formula: Br^- + Ar = (Br^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.80	kcal/mol	Ther	Zhao, Yourshaw, et al., 1994	gas phase; B
Δ_rH°	1.40	kcal/mol	Mobl	Gatland, 1984, 2	gas phase; B,M

+ Argon = ( • Argon )

By formula: CH₃⁺ + Ar = (CH₃⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.3 ± 2.0	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.1	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • Argon ) + Argon = ( • 2 Argon )

By formula: (CH₃⁺ • Ar) + Ar = (CH₃⁺ • 2Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.3 ± 0.2	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	15.7	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 2 Argon ) + Argon = ( • 3 Argon )

By formula: (CH₃⁺ • 2Ar) + Ar = (CH₃⁺ • 3Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.0 ± 0.2	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	22.3	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 3 Argon ) + Argon = ( • 4 Argon )

By formula: (CH₃⁺ • 3Ar) + Ar = (CH₃⁺ • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.0 ± 0.2	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.1	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 4 Argon ) + Argon = ( • 5 Argon )

By formula: (CH₃⁺ • 4Ar) + Ar = (CH₃⁺ • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.9 ± 0.2	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	20.6	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 5 Argon ) + Argon = ( • 6 Argon )

By formula: (CH₃⁺ • 5Ar) + Ar = (CH₃⁺ • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.9 ± 0.3	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.0	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 6 Argon ) + Argon = ( • 7 Argon )

By formula: (CH₃⁺ • 6Ar) + Ar = (CH₃⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.9 ± 0.4	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	21.2	cal/mol*K	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; M

( • 7 Argon ) + Argon = ( • 8 Argon )

By formula: (CH₃⁺ • 7Ar) + Ar = (CH₃⁺ • 8Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.93	kcal/mol	PHPMS	Hiraoka, Kudaka, et al., 1991	gas phase; Entropy change calculated or estimated; M

CO⁺ + Argon = (CO⁺ • Argon )

By formula: CO⁺ + Ar = (CO⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	16.1 ± 1.4	kcal/mol	PIPECO	Norwood, Guo, et al., 1989	gas phase; CO+(X) ground state; M

+ Argon = ( • Argon )

By formula: CO₂⁺ + Ar = (CO₂⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.0	kcal/mol	PI	Pratt and Dehmer, 1983	gas phase; M

+ Argon = ( • Argon )

By formula: Co⁺ + Ar = (Co⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	11.8	kcal/mol	PDis	Asher, Bellert, et al., 1994	RCD

+ Argon = ( • Argon )

By formula: Cr⁺ + Ar = (Cr⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.9 ± 0.4	kcal/mol	SIDT	Kemper, Hsu, et al., 1991	gas phase; Δ_rH(0 K) = 6.55 kcal/mol, Δ_rS(100 K) = 14.4 cal/mol*K; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	15.8	cal/mol*K	SIDT	Kemper, Hsu, et al., 1991	gas phase; Δ_rH(0 K) = 6.55 kcal/mol, Δ_rS(100 K) = 14.4 cal/mol*K; M

+ Argon = ( • Argon )

By formula: Cs⁺ + Ar = (Cs⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.95	kcal/mol	IMob	Gatland, 1984	gas phase; M
Δ_rH°	1.46	kcal/mol	SCATTERING	Gislason, 1984	gas phase; M
Δ_rH°	1.96	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	2.28	kcal/mol	IMob	Takebe, 1983	gas phase; M
Δ_rH°	2.3	kcal/mol	IMob	Takebe, 1983	gas phase; values from this reference are consistently too high; M

D₃⁺ + Argon = (D₃⁺ • Argon )

By formula: D₃⁺ + Ar = (D₃⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7.0 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	14.5	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • Argon ) + Argon = (D₃⁺ • 2 Argon )

By formula: (D₃⁺ • Ar) + Ar = (D₃⁺ • 2Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.8 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.5	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 2 Argon ) + Argon = (D₃⁺ • 3 Argon )

By formula: (D₃⁺ • 2Ar) + Ar = (D₃⁺ • 3Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.4 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 3 Argon ) + Argon = (D₃⁺ • 4 Argon )

By formula: (D₃⁺ • 3Ar) + Ar = (D₃⁺ • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.4 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.6	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 4 Argon ) + Argon = (D₃⁺ • 5 Argon )

By formula: (D₃⁺ • 4Ar) + Ar = (D₃⁺ • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.3 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 5 Argon ) + Argon = (D₃⁺ • 6 Argon )

By formula: (D₃⁺ • 5Ar) + Ar = (D₃⁺ • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.2 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(D₃⁺ • 6 Argon ) + Argon = (D₃⁺ • 7 Argon )

By formula: (D₃⁺ • 6Ar) + Ar = (D₃⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	25.2	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

+ Argon = ArF^-

By formula: F^- + Ar = ArF^-

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.00	kcal/mol	TDAs	Wada, Kikkawa, et al., 2007	gas phase; Entropy estimated; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	-3.96	kcal/mol	TDAs	Wada, Kikkawa, et al., 2007	gas phase; Entropy estimated; B

+ Argon = ( • Argon )

By formula: Fe⁺ + Ar = (Fe⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.6 ± 1.9	kcal/mol	CIDT	Rodgers and Armentrout, 2000	RCD

+ Argon = ( • Argon )

By formula: H₂⁺ + Ar = (H₂⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	24.	kcal/mol	SIFT	Bedford and Smith, 1990	gas phase; switching reaction(Ar+)Ar, Δ_rH>; M

H₃⁺ + Argon = (H₃⁺ • Argon )

By formula: H₃⁺ + Ar = (H₃⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	6.7 ± 0.2	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Δ_rH°	7.5 ± 0.8	kcal/mol	SIFT	Bedford and Smith, 1990	gas phase; switching reaction(H3+)H2, Hiraoka and Mori, 1989; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.4	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • Argon ) + Argon = (H₃⁺ • 2 Argon )

By formula: (H₃⁺ • Ar) + Ar = (H₃⁺ • 2Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.6 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.0	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • 2 Argon ) + Argon = (H₃⁺ • 3 Argon )

By formula: (H₃⁺ • 2Ar) + Ar = (H₃⁺ • 3Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.3 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • 3 Argon ) + Argon = (H₃⁺ • 4 Argon )

By formula: (H₃⁺ • 3Ar) + Ar = (H₃⁺ • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.5 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.1	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • 4 Argon ) + Argon = (H₃⁺ • 5 Argon )

By formula: (H₃⁺ • 4Ar) + Ar = (H₃⁺ • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.3 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	16.7	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • 5 Argon ) + Argon = (H₃⁺ • 6 Argon )

By formula: (H₃⁺ • 5Ar) + Ar = (H₃⁺ • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.2 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	18.7	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

(H₃⁺ • 6 Argon ) + Argon = (H₃⁺ • 7 Argon )

By formula: (H₃⁺ • 6Ar) + Ar = (H₃⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.1	kcal/mol	PHPMS	Hiraoka and Mori, 1989	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	23.0	cal/mol*K	PHPMS	Hiraoka and Mori, 1989	gas phase; M

Hg⁺ + Argon = (Hg⁺ • Argon )

By formula: Hg⁺ + Ar = (Hg⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	5.3 ± 0.4	kcal/mol	PI	Linn, Brom, et al., 1985	gas phase; M

+ Argon = ( • Argon )

By formula: I^- + Ar = (I^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.60	kcal/mol	Ther	Zhao, Yourshaw, et al., 1994	gas phase; B

+ Argon = ( • Argon )

By formula: K⁺ + Ar = (K⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.8 ± 0.7	kcal/mol	AVG	N/A	Average of 9 values; Individual data points

Kr⁺ + Argon = (Kr⁺ • Argon )

By formula: Kr⁺ + Ar = (Kr⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	12.2	kcal/mol	PI	Dehmer and Pratt, 1982	gas phase; M
Δ_rH°	13.6	kcal/mol	PI	Ng, Tiedemann, et al., 1977	gas phase; M

+ Argon = ( • Argon )

By formula: Li⁺ + Ar = (Li⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	7. ± 1.	kcal/mol	AVG	N/A	Average of 4 out of 6 values; Individual data points
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	7.	cal/mol*K	DT	McKnight and Sawina, 1973	gas phase; Δ_rS approximate; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
1.4	294.	IMob	Cassidy and Elford, 1985	gas phase; M
1.9	319.	DT	Keller, Beyer, et al., 1973	gas phase; LOW E/N; M
2.6	215.	DT	McKnight and Sawina, 1973	gas phase; Δ_rS approximate; M

+ Argon = ( • Argon )

By formula: Mg⁺ + Ar = (Mg⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.3 ± 1.6	kcal/mol	CIDT	Andersen, Muntean, et al., 2000	RCD

N⁺ + Argon = (N⁺ • Argon )

By formula: N⁺ + Ar = (N⁺ • Ar)

Enthalpy of reaction

Δ_rH° (kcal/mol)	T (K)	Method	Reference	Comment
28. (+11.,-0.)		CID	Haynes, Freysinger, et al., 1995	gas phase; giuded ion beam CID; M

+ Argon = ( • Argon )

By formula: NO^- + Ar = (NO^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.30 ± 0.90	kcal/mol	N/A	Hendricks, de Clercq, et al., 2002	gas phase; B
Δ_rH°	1.60 ± 0.30	kcal/mol	N/A	Bowen and Eaton, 1988	gas phase; B

+ Argon = ( • Argon )

By formula: N₂⁺ + Ar = (N₂⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	26.8	kcal/mol	PD/KERD	Kim and Bowers, 1990	gas phase; switching reaction(N2+)N2; Hiraoka and Nakajima, 1988; M
Δ_rH°	25.4	kcal/mol	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)N2; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.5	cal/mol*K	PD/KERD	Kim and Bowers, 1990	gas phase; switching reaction(N2+)N2; Hiraoka and Nakajima, 1988; M
Δ_rS°	13.7	cal/mol*K	PHPMS	Teng and Conway, 1973	gas phase; switching reaction(N2+)N2; M

( • Argon ) + Argon = ( • 2 Argon )

By formula: (N₂⁺ • Ar) + Ar = (N₂⁺ • 2Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.8	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Δ_rH>; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Δ_rH>; M

( • 2 Argon ) + Argon = ( • 3 Argon )

By formula: (N₂⁺ • 2Ar) + Ar = (N₂⁺ • 3Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.7 ± 0.2	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	13.7	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M

( • 3 Argon ) + Argon = ( • 4 Argon )

By formula: (N₂⁺ • 3Ar) + Ar = (N₂⁺ • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.7 ± 0.2	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.9	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M

( • 4 Argon ) + Argon = ( • 5 Argon )

By formula: (N₂⁺ • 4Ar) + Ar = (N₂⁺ • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.0	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M

( • 5 Argon ) + Argon = ( • 6 Argon )

By formula: (N₂⁺ • 5Ar) + Ar = (N₂⁺ • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.6 ± 0.2	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.4	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M

( • 6 Argon ) + Argon = ( • 7 Argon )

By formula: (N₂⁺ • 6Ar) + Ar = (N₂⁺ • 7Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.5 ± 0.2	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.3	cal/mol*K	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; M

( • 7 Argon ) + Argon = ( • 8 Argon )

By formula: (N₂⁺ • 7Ar) + Ar = (N₂⁺ • 8Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.53	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	N/A	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M

( • 8 Argon ) + Argon = ( • 9 Argon )

By formula: (N₂⁺ • 8Ar) + Ar = (N₂⁺ • 9Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.52	kcal/mol	PHPMS	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	17.	cal/mol*K	N/A	Hiraoka, Mori, et al., 1992	gas phase; Entropy change calculated or estimated; M

+ Argon = ( • Argon )

By formula: Na⁺ + Ar = (Na⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	3.7 ± 2.1	kcal/mol	CIDT	Armentrout and Rodgers, 2000	RCD
Δ_rH°	3.70	kcal/mol	SCATTERING	Gislason, 1984	gas phase; M
Δ_rH°	4.39	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	4.4	kcal/mol	DT	McKnight and Sawina, 1973	gas phase; M
Δ_rH°	4.87	kcal/mol	IMob	Takebe, 1983	gas phase; M

O^- + Argon = (O^- • Argon )

By formula: O^- + Ar = (O^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • Argon ) + Argon = (O^- • 2 Argon )

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

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

(O^- • 2 Argon ) + Argon = (O^- • 3 Argon )

By formula: (O^- • 2Ar) + Ar = (O^- • 3Ar)

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

(O^- • 3 Argon ) + Argon = (O^- • 4 Argon )

By formula: (O^- • 3Ar) + Ar = (O^- • 4Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 4 Argon ) + Argon = (O^- • 5 Argon )

By formula: (O^- • 4Ar) + Ar = (O^- • 5Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 5 Argon ) + Argon = (O^- • 6 Argon )

By formula: (O^- • 5Ar) + Ar = (O^- • 6Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 6 Argon ) + Argon = (O^- • 7 Argon )

By formula: (O^- • 6Ar) + Ar = (O^- • 7Ar)

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

(O^- • 7 Argon ) + Argon = (O^- • 8 Argon )

By formula: (O^- • 7Ar) + Ar = (O^- • 8Ar)

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

(O^- • 8 Argon ) + Argon = (O^- • 9 Argon )

By formula: (O^- • 8Ar) + Ar = (O^- • 9Ar)

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

(O^- • 9 Argon ) + Argon = (O^- • 10 Argon )

By formula: (O^- • 9Ar) + Ar = (O^- • 10Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.7 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 10 Argon ) + Argon = (O^- • 11 Argon )

By formula: (O^- • 10Ar) + Ar = (O^- • 11Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 11 Argon ) + Argon = (O^- • 12 Argon )

By formula: (O^- • 11Ar) + Ar = (O^- • 12Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.8 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 12 Argon ) + Argon = (O^- • 13 Argon )

By formula: (O^- • 12Ar) + Ar = (O^- • 13Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 13 Argon ) + Argon = (O^- • 14 Argon )

By formula: (O^- • 13Ar) + Ar = (O^- • 14Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 14 Argon ) + Argon = (O^- • 15 Argon )

By formula: (O^- • 14Ar) + Ar = (O^- • 15Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.4 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 15 Argon ) + Argon = (O^- • 16 Argon )

By formula: (O^- • 15Ar) + Ar = (O^- • 16Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 16 Argon ) + Argon = (O^- • 17 Argon )

By formula: (O^- • 16Ar) + Ar = (O^- • 17Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 17 Argon ) + Argon = (O^- • 18 Argon )

By formula: (O^- • 17Ar) + Ar = (O^- • 18Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 18 Argon ) + Argon = (O^- • 19 Argon )

By formula: (O^- • 18Ar) + Ar = (O^- • 19Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 19 Argon ) + Argon = (O^- • 20 Argon )

By formula: (O^- • 19Ar) + Ar = (O^- • 20Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 20 Argon ) + Argon = (O^- • 21 Argon )

By formula: (O^- • 20Ar) + Ar = (O^- • 21Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 21 Argon ) + Argon = (O^- • 22 Argon )

By formula: (O^- • 21Ar) + Ar = (O^- • 22Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 22 Argon ) + Argon = (O^- • 23 Argon )

By formula: (O^- • 22Ar) + Ar = (O^- • 23Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 23 Argon ) + Argon = (O^- • 24 Argon )

By formula: (O^- • 23Ar) + Ar = (O^- • 24Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.1 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 24 Argon ) + Argon = (O^- • 25 Argon )

By formula: (O^- • 24Ar) + Ar = (O^- • 25Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

(O^- • 25 Argon ) + Argon = (O^- • 26 Argon )

By formula: (O^- • 25Ar) + Ar = (O^- • 26Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	0.2 ± 2.0	kcal/mol	N/A	Arnold, Hendricks, et al., 1995	gas phase; EA given is Vertical Detachment Energy. Affinity: difference between successive EAs in (Y); B

+ Argon = ( • Argon )

By formula: O₂^- + Ar = (O₂^- • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1.66	kcal/mol	N/A	Bowen and Eaton, 1988	gas phase; Bound by 70 meV relative to EA(O2-.); B

+ Argon = ( • Argon )

By formula: Rb⁺ + Ar = (Rb⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	2.03	kcal/mol	IMob	Gatland, 1984	gas phase; M
Δ_rH°	1.98	kcal/mol	IMob	Viehland, 1984	gas phase; M
Δ_rH°	2.84	kcal/mol	IMob	Takebe, 1983	gas phase; M

Xe⁺ + Argon = (Xe⁺ • Argon )

By formula: Xe⁺ + Ar = (Xe⁺ • Ar)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	4.1	kcal/mol	PI	Dehmer and Pratt, 1982	gas phase; M
Δ_rH°	6.0	kcal/mol	SIFT	Jones, Lister, et al., 1980	gas phase; M
Δ_rH°	3.2	kcal/mol	PI	Ng, Tiedemann, et al., 1977	gas phase; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	19.4	cal/mol*K	SIFT	Jones, Lister, et al., 1980	gas phase; M

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, Ion clustering data, References, Notes

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

Spectrum

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Owner	NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.
Origin	DOW CHEMICAL COMPANY / ASTM E14-UNCERTIFIED SPECTRUM 1
NIST MS number	34321

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References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes

Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A., CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

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

Streng, 1971
Streng, A.G., Miscibility and Compatibility of Some Liquid and Solidified Gases at Low Temperature, J. Chem. Eng. Data, 1971, 16, 357. [all data]

Gosman, McCarty, et al., 1969
Gosman, A.L.; McCarty, R.D.; Hust, J.G., Thermodynamic Properties of Argon from the Triple Point to 300 K at Pressures to 1000 Atmospheres, Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. NSRDS-NBS 27, 1969. [all data]

Van't Zelfde, Omar, et al., 1968
Van't Zelfde, P.; Omar, M.H.; LePair-Schroten, H.G.M.; Dokoupil, Z., Solid-liquid equilibrium diagram for the argon + methane system., Physica (Amsterdam), 1968, 38, 241-51. [all data]

Angus, Armstrong, et al., 1972
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Notes

Symbols used in this document:

IE (evaluated)	Recommended ionization energy
P_c	Critical pressure
P_triple	Triple point pressure
S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
T	Temperature
T_boil	Boiling point
T_c	Critical temperature
T_fus	Fusion (melting) point
T_triple	Triple point temperature
d(ln(k_H))/d(1/T)	Temperature dependence parameter for Henry's Law constant
k°_H	Henry's Law constant at 298.15K
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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NIST Chemistry WebBook, SRD 69

Argon

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Gas phase thermochemistry data

Gas Phase Heat Capacity (Shomate Equation)

Phase change data

Antoine Equation Parameters

Reaction thermochemistry data

Reactions 1 to 50

Free energy of reaction

Free energy of reaction

Henry's Law data

Henry's Law constant (water solution)

Gas phase ion energetics data

Ionization energy determinations

Ion clustering data

Clustering reactions

Free energy of reaction

Free energy of reaction

Enthalpy of reaction

Mass spectrum (electron ionization)

Spectrum

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