Selected ATcT [1, 2] enthalpy of formation based on version 1.172 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.156 to include species relevant to a study of photodissociation of formamide[4].

Diiodine

Formula: I2 (g)
CAS RN: 7553-56-2
ATcT ID: 7553-56-2*0
SMILES: II
InChI: InChI=1S/I2/c1-2
InChIKey: PNDPGZBMCMUPRI-UHFFFAOYSA-N
Hills Formula: I2

2D Image:

II
Aliases: I2; Diiodine; Iodine molecule; Iodine; Molecular iodine; Diatomic iodine
Relative Molecular Mass: 253.808940 ± 0.000060

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
65.49762.417± 0.0041kJ/mol

3D Image of I2 (g)

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Top contributors to the provenance of ΔfH° of I2 (g)

The 5 contributors listed below account for 93.3% of the provenance of ΔfH° of I2 (g).

Please note: The list is limited to 20 most important contributors or, if less, a number sufficient to account for 90% of the provenance. The Reference acts as a further link to the relevant references and notes for the measurement. The Measured Quantity is normaly given in the original units; in cases where we have reinterpreted the original measurement, the listed value may differ from that given by the authors. The quoted uncertainty is the a priori uncertainty used as input when constructing the initial Thermochemical Network, and corresponds either to the value proposed by the original authors or to our estimate; if an additional multiplier is given in parentheses immediately after the prior uncertainty, it corresponds to the factor by which the prior uncertainty needed to be multiplied during the ATcT analysis in order to make that particular measurement consistent with the prevailing knowledge contained in the Thermochemical Network.

Contribution
(%)
TN
ID
Reaction Measured Quantity Reference
21.81271.2 I2 (cr,l) → I2 (g) ΔrG°(298.15 K) = 4.616 ± 0.002 kcal/molGiauque 1931, Baxter 1915, Baxter 1907, 3rd Law, est unc
21.81271.4 I2 (cr,l) → I2 (g) ΔrG°(298.15 K) = 4.618 ± 0.002 kcal/molGerry 1932, Giauque 1931, 3rd Law, est unc
21.81276.6 I2 (cr,l) → I2 (g) ΔrH°(298.15 K) = 14.919 ± 0.002 kcal/molShirley 1959, Baxter 1907, Baxter 1915, 2nd Law
21.81276.8 I2 (cr,l) → I2 (g) ΔrH°(325.8 K) = 14.799 ± 0.002 kcal/molShirley 1959, Baxter 1907, Baxter 1915, 2nd Law
5.91270.8 I2 (cr,l) → I2 (g) ΔrG°(298.15 K) = 4.614 ± 0.002 (×1.915) kcal/molBaxter 1915, Baxter 1907, 3rd Law

Top 10 species with enthalpies of formation correlated to the ΔfH° of I2 (g)

Please note: The correlation coefficients are obtained by renormalizing the off-diagonal elements of the covariance matrix by the corresponding variances.
The correlation coefficient is a number from -1 to 1, with 1 representing perfectly correlated species, -1 representing perfectly anti-correlated species, and 0 representing perfectly uncorrelated species.


Correlation
Coefficent
(%)
Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
99.9 IodineI (g, 2P3/2)[I]107.157106.757± 0.0021kJ/mol126.904470 ±
0.000030
14362-44-8*1
99.9 IodineI (g, 2P1/2)[I]198.109197.709± 0.0021kJ/mol126.904470 ±
0.000030
14362-44-8*2
99.9 IodineI (g)[I]107.157106.757± 0.0021kJ/mol126.904470 ±
0.000030
14362-44-8*0
98.5 IodideI- (g)[I-]-187.996-188.396± 0.0021kJ/mol126.905019 ±
0.000030
20461-54-5*0
31.1 Iodine cationI+ (g)[I+]1115.5491115.149± 0.0062kJ/mol126.903921 ±
0.000030
22541-93-1*0
22.5 Diiodine cation[I2]+ (g)I[I+]963.523960.408± 0.018kJ/mol253.808391 ±
0.000060
28712-14-3*0
16.1 Iodine monochlorideICl (g)ICl19.02417.391± 0.013kJ/mol162.35717 ±
0.00090
7790-99-0*0
5.5 Hydrogen iodideHI (g)I28.64526.470± 0.036kJ/mol127.912410 ±
0.000076
10034-85-2*0
4.7 DiiodineI2 (aq, undissoc)II23.243± 0.082kJ/mol253.808940 ±
0.000060
7553-56-2*1000
3.1 Iodine monochlorideICl (cr)ICl-36.511-35.537± 0.063kJ/mol162.35717 ±
0.00090
7790-99-0*510

Most Influential reactions involving I2 (g)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Influence
Coefficient
TN
ID
Reaction Measured Quantity Reference
0.9581280.1 [I2]- (g) → I2 (g) ΔrH°(0 K) = 2.524 ± 0.005 eVZanni 1997
0.9246313.1 CF3Br (g) I2 (g) → CF3I (g) IBr (g) ΔrH°(298.15 K) = 9.55 ± 0.06 kcal/molLord 1967, as quoted by Cox 1970
0.7801297.1 HI (g) → H2 (g) I2 (g) ΔrG°(721.5 K) = 23.625 ± 0.080 kJ/molTaylor 1941, 3rd Law
0.6711277.1 I2 (g) → I2 (aq, undissoc) ΔrG°(298.15 K) = -2.727 ± 0.10 kJ/molSanemasa 1984
0.5987564.1 CHICHI (g, cis) → HCCH (g) I2 (g) ΔrG°(600 K) = 0.60 ± 0.10 kcal/molFuruyama 1968
0.5987565.1 CHICHI (g, trans) → HCCH (g) I2 (g) ΔrG°(600 K) = 1.26 ± 0.10 kcal/molFuruyama 1968
0.4981279.2 I2 (g) → [I2]+ (g) ΔrH°(0 K) = 75069 ± 2 cm-1Cockett 1996
0.4981279.1 I2 (g) → [I2]+ (g) ΔrH°(0 K) = 75069 ± 2 cm-1Cockett 1995
0.4461290.9 I2 (g) → I (g, 2P3/2) I (g, 2P1/2) ΔrH°(0 K) = 20043.176 ± 0.016 cm-1Gerstenkorn 1983
0.3171352.1 [I3]- (g) → I2 (g) I- (g) ΔrH°(0 K) = 126 ± 6 kJ/molDo 1997
0.3161290.11 I2 (g) → I (g, 2P3/2) I (g, 2P1/2) ΔrH°(0 K) = 20043.159 ± 0.019 cm-1Tromp 1983
0.2391351.1 [I3]+ (g) → I2 (g) I+ (g) ΔrH°(298.15 K) = 56.8 ± 2 kcal/molThanthiriwatte 2014, est unc
0.2181271.4 I2 (cr,l) → I2 (g) ΔrG°(298.15 K) = 4.618 ± 0.002 kcal/molGerry 1932, Giauque 1931, 3rd Law, est unc
0.2181271.2 I2 (cr,l) → I2 (g) ΔrG°(298.15 K) = 4.616 ± 0.002 kcal/molGiauque 1931, Baxter 1915, Baxter 1907, 3rd Law, est unc
0.2181276.8 I2 (cr,l) → I2 (g) ΔrH°(325.8 K) = 14.799 ± 0.002 kcal/molShirley 1959, Baxter 1907, Baxter 1915, 2nd Law
0.2181276.6 I2 (cr,l) → I2 (g) ΔrH°(298.15 K) = 14.919 ± 0.002 kcal/molShirley 1959, Baxter 1907, Baxter 1915, 2nd Law
0.1631352.2 [I3]- (g) → I2 (g) I- (g) ΔrH°(298.15 K) = 32.0 ± 2 kcal/molThanthiriwatte 2014, est unc
0.1306311.1 CHF3 (g) I2 (g) → CF3I (g) HI (g) ΔrH°(298.15 K) = 17.10 ± 0.34 kcal/molGoy 1967, as quoted by Cox 1970
0.1131298.1 HI (g) → 1/2 H2 (g) + 1/2 I2 (g) ΔrG°(704 K) = 11.571 ± 0.028 (×3.748) kJ/molRittenberg 1934, note HI, 3rd Law
0.1071277.5 I2 (g) → I2 (aq, undissoc) ΔrG°(298.15 K) = -2.699 ± 0.25 kJ/molPalmer 1985, Sander 2023, NIST WebBook, est unc


References
1   B. Ruscic, R. E. Pinzon, M. L. Morton, G. von Laszewski, S. Bittner, S. G. Nijsure, K. A. Amin, M. Minkoff, and A. F. Wagner,
Introduction to Active Thermochemical Tables: Several "Key" Enthalpies of Formation Revisited.
J. Phys. Chem. A 108, 9979-9997 (2004) [DOI: 10.1021/jp047912y]
2   B. Ruscic, R. E. Pinzon, G. von Laszewski, D. Kodeboyina, A. Burcat, D. Leahy, D. Montoya, and A. F. Wagner,
Active Thermochemical Tables: Thermochemistry for the 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005) [DOI: 10.1088/1742-6596/16/1/078]
3   B. Ruscic and D. H. Bross,
Active Thermochemical Tables (ATcT) values based on ver. 1.172 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   K. L. Caster, N. A. Seifert, B. Ruscic, A. W. Jasper, and K. Prozument,
Dynamics of HCN, NHC, and HNCO Formation in the 193 nm Photodissociation of Formamide
J. Phys. Chem. A (in press) (2024) [DOI: 10.1021/acs.jpca.4c02232]
5   B. Ruscic,
Uncertainty Quantification in Thermochemistry, Benchmarking Electronic Structure Computations, and Active Thermochemical Tables.
Int. J. Quantum Chem. 114, 1097-1101 (2014) [DOI: 10.1002/qua.24605]
6   B. Ruscic and D. H. Bross,
Thermochemistry
Computer Aided Chem. Eng. 45, 3-114 (2019) [DOI: 10.1016/B978-0-444-64087-1.00001-2]

Formula
The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.

Uncertainties
The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [5] and Ruscic and Bross[6]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.

Website Functionality Credits
The reorganization of the website was developed and implemented by David H. Bross (ANL).
The find function is based on the complete Species Dictionary entries for the appropriate version of the ATcT TN.
The molecule images are rendered by Indigo-depict.
The XYZ renderings are based on Jmol: an open-source Java viewer for chemical structures in 3D. http://www.jmol.org/.

Acknowledgement
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Contract No. DE-AC02-06CH11357.