Selected ATcT [1, 2] enthalpy of formation based on version 1.156 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.148 to include species relevant to a recent study of the oxidation of ethylene [4] as well as new measurements that led to refining the thermochemistry of CF and SiF and their cations [5].

Formaldehyde

Formula: CH2O (aq, unhydrol)
CAS RN: 50-00-0
ATcT ID: 50-00-0*1000
SMILES: C=O
InChI: InChI=1S/CH2O/c1-2/h1H2
InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-N
Hills Formula: C1H2O1

2D Image:

C=O
Aliases: Formaldehyde; Methanal; Formaldehyde monomer; Methyl aldehyde; Oxymethylene; Oxymethylene monomer; Methylene oxide; H2CO; CH2O; H2CO g; CH2O g; H2C=O
Relative Molecular Mass: 30.02598 ± 0.00087

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
-165.65± 0.22kJ/mol

Top contributors to the provenance of ΔfH° of CH2O (aq, unhydrol)

The 16 contributors listed below account for 90.1% of the provenance of ΔfH° of CH2O (aq, unhydrol).

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
69.13022.3 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(298.15 K) = -19.98 ± 0.21 kJ/molWarneck 2012, Betterton 1988, Zhou 1990, 3rd Law
9.03022.5 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(293 K) = -20.79 ± 0.58 kJ/molAllou 2011, 3rd Law
3.83081.11 [HCO]+ (g) → H+ (g) CO (g) ΔrH°(0 K) = 586.51 ± 0.2 kJ/molCzako 2008
1.93009.3 CO (g) H2 (g) → CH2O (g) ΔrH°(0 K) = 8.39 ± 0.28 kJ/molCzako 2009
1.13022.4 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(298.15 K) = -56.4 ± 1.6 kJ/molWarneck 2012, Betterton 1988, Zhou 1990, 2nd Law
0.73022.7 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(293 K) = -20.6 ± 2 kJ/molStaudinger 1996, 3rd Law, est unc, Allou 2011
0.53083.9 CO (g) [NH4]+ (g) → [HCO]+ (g) NH3 (g) ΔrH°(0 K) = 259.89 ± 0.3 kJ/molCzako 2008
0.53008.8 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.44 ± 0.25 kcal/molKarton 2006
0.53008.7 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.44 ± 0.25 kcal/molKarton 2006
0.42989.1 [CH2OH]+ (g) → CH2O (g) H+ (g) ΔrH°(0 K) = 704.98 ± 0.39 kJ/molCzako 2009
0.43074.9 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1132.68 ± 0.56 kJ/molHarding 2008
0.33008.6 CH2O (g) → CH4 (g) CO2 (g) ΔrH°(0 K) = -59.52 ± 0.30 kcal/molKarton 2006
0.33011.1 CH2O (g) O2 (g) → CO2 (g) H2O (cr,l) ΔrH°(299.65 K) = -570.69 ± 0.40 (×1.795) kJ/molFletcher 1970, note std dev
0.21652.8 [NH4]+ (g) → NH3 (g) H+ (g) ΔrH°(0 K) = 846.40 ± 0.3 kJ/molCzako 2008
0.23074.7 HCO (g) → H (g) O (g) C (g) ΔrH°(0 K) = 1133.05 ± 0.70 kJ/molHarding 2008
0.22270.9 C (graphite) CO2 (g) → 2 CO (g) ΔrG°(1165 K) = -33.545 ± 0.058 kJ/molSmith 1946, note COf, 3rd Law

Top 10 species with enthalpies of formation correlated to the ΔfH° of CH2O (aq, unhydrol)

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
43.6 FormaldehydeCH2O (g)C=O-105.381-109.221± 0.095kJ/mol30.02598 ±
0.00087
50-00-0*0
43.6 FormaldehydeCH2O (g, singlet)C=O-105.381-109.221± 0.095kJ/mol30.02598 ±
0.00087
50-00-0*2
43.6 FormaldehydeCH2O (g, para singlet)C=O-105.381-109.221± 0.095kJ/mol30.02598 ±
0.00087
50-00-0*21
43.6 FormaldehydeCH2O (g, ortho singlet)C=O-105.255-109.221± 0.095kJ/mol30.02598 ±
0.00087
50-00-0*22
43.6 FormaldehydeCH2O (g, triplet)C=O196.010192.707± 0.095kJ/mol30.02598 ±
0.00087
50-00-0*1
43.4 FormylHCO (g)[CH]=O41.38941.763± 0.095kJ/mol29.01804 ±
0.00086
2597-44-6*0
43.3 Oxomethylium[HCO]+ (g)[CH+]=O827.765827.181± 0.095kJ/mol29.01749 ±
0.00086
17030-74-9*0
43.0 Formaldehyde cation[CH2O]+ (g)C=[O+]944.861941.240± 0.096kJ/mol30.02543 ±
0.00087
54288-05-0*0
10.0 HydroxymethyleneHCOH (g, trans)[CH]O112.71108.94± 0.27kJ/mol30.02598 ±
0.00087
19710-56-6*1
10.0 HydroxymethyleneHCOH (g)[CH]O112.71108.95± 0.27kJ/mol30.02598 ±
0.00087
19710-56-6*0

Most Influential reactions involving CH2O (aq, unhydrol)

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
0.8543022.3 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(298.15 K) = -19.98 ± 0.21 kJ/molWarneck 2012, Betterton 1988, Zhou 1990, 3rd Law
0.5023023.1 CH2O (cr, paraformaldehyde) → CH2O (aq, unhydrol) ΔrH°(298.15 K) = 2.4 ± 0.5 kcal/molDelepine 1942, note CH2O, est unc
0.1123022.5 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(293 K) = -20.79 ± 0.58 kJ/molAllou 2011, 3rd Law
0.0143022.4 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(298.15 K) = -56.4 ± 1.6 kJ/molWarneck 2012, Betterton 1988, Zhou 1990, 2nd Law
0.0093022.7 CH2O (g) → CH2O (aq, unhydrol) ΔrG°(293 K) = -20.6 ± 2 kJ/molStaudinger 1996, 3rd Law, est unc, Allou 2011
0.0013022.6 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(293 K) = -53.4 ± 4.5 kJ/molAllou 2011, 2nd Law
0.0013022.2 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(298.15 K) = -14.8 ± 0.2 (×6.583) kcal/molWalker 1933, est unc
0.0013022.1 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(298.15 K) = -14.9 ± 0.2 (×7.179) kcal/molDelepine 1942, note CH2O, est unc
0.0003022.8 CH2O (g) → CH2O (aq, unhydrol) ΔrH°(293 K) = -56.5 ± 10 kJ/molStaudinger 1996, 2nd Law, est unc, Allou 2011


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. 1.156 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   N. A. Seifert, B. Ruscic, R. Sivaramakrishnan, and K. Prozument,
The C2H4O Isomers in the Oxidation of Ethylene
J. Mol. Spectrosc. 398, 111847/1-8 (2023) [DOI: 10.1016/j.jms.2023.111847]
5   U. Jacovella, B. Ruscic, N. L. Chen, H.-L. Le, S. Boyé-Péronne, S. Hartweg, M. Roy-Chowdhury, G. A. Garcia, J.-C. Loison, and B. Gans,
Refining Thermochemical Properties of CF, SiF, and Their Cations by Combining Photoelectron Spectroscopy, Quantum Chemical Calculations, and the Active Thermochemical Tables Approach
Phys. Chem. Chem. Phys. 25, 30838-30847 (2023) [DOI: 10.1039/D3CP04244H]
6   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]
7   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 [6] and Ruscic and Bross[7]).
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.