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].

Hydrogen difluoride cation

Formula: [FHF]+ (g, triplet ?)

CAS RN: 126950-54-7

ATcT ID: 126950-54-7*1

SMILES: F[H][F+]

InChI: InChI=1S/F2H/c1-3-2/q+1

InChIKey: PHSIALIAIMOJSS-UHFFFAOYSA-N

Hills Formula: F2H1+

2D Image:

Aliases: Hydrogen difluoride cation; Hydrogen difluoride ion (1+); Difluorohydrogen cation; Difluorohydrogen ion (1+); [FHF]+; FHF+

Relative Molecular Mass: 39.004198 ± 0.000070

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
1241.	1238.	± 17.	kJ/mol

3D Image of [FHF]+ (g, triplet ?)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [FHF]+ (g, triplet ?)

The 2 contributors listed below account for 99.9% of the provenance of Δ_fH° of [FHF]+ (g, triplet ?).

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
69.2	613.2	[FHF]+ (g, triplet ?) → [HF]+ (g) + F (g)	Δ_rH°(0 K) = 1.21 ± 0.2 eV	Ruscic MP2, est unc
30.6	614.1	[FFH]+ (g) → [FHF]+ (g, triplet ?)	Δ_rH°(0 K) = 0.82 ± 0.3 eV	Li 2000, est unc

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [FHF]+ (g, triplet ?)

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	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
2.8	Hydrogen difluoride cation	[FFH]+ (g)		1174.3	1171.3	± 1.5	kJ/mol	39.004198 ± 0.000070	126950-54-70
2.8	Hydrogen difluoride cation	[FFH]+ (g, singlet)		1174.3	1171.3	± 1.5	kJ/mol	39.004198 ± 0.000070	126950-54-72

Most Influential reactions involving [FHF]+ (g, triplet ?)

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
0.692	613.2	[FHF]+ (g, triplet ?) → [HF]+ (g) + F (g)	Δ_rH°(0 K) = 1.21 ± 0.2 eV	Ruscic MP2, est unc
0.309	614.1	[FFH]+ (g) → [FHF]+ (g, triplet ?)	Δ_rH°(0 K) = 0.82 ± 0.3 eV	Li 2000, 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 21^st 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.