CeC2: enthalpy of formation

8 accepted literature formation-enthalpy value(s) (experimental 8); experimental median -30.4 kJ/mol-atom (n = 8); Materials Project -15.378 kJ/mol-atom (mp-aaaaaeff); OQMD -8.01 kJ/mol-atom (oqmd-13373).

Systems: C–Ce

Literature values

Enthalpy of formation of CeC2 reported in the literature (8)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-40.03 kJ/mol-atom ± 3.7	CeC2	298.15	experimental	Dynamic effusion MS	C–Ce	[1] Peng 2011 cites Vidhya 2003 doi	Table 2, p. 2, row 16 report
-34.9 kJ/mol-atom	CeC2	298.15	experimental	Knudsen effusion	C–Ce	[1] Peng 2011 cites Faircloth 1968 doi	Table 2, p. 2, row 15 report
-32.4 kJ/mol-atom ± 1.8	CeC2	298.15	experimental	Bomb calorimetry	C–Ce	[1] Peng 2011 cites Baker 1971 doi	Table 2, p. 2, row 14 report
-31.3 kJ/mol-atom	CeC2	298.15	experimental	Controlled CO pressure	C–Ce	[1] Peng 2011 cites Pialoux 1988 doi	Table 2, p. 2, row 13 report
-29.5 kJ/mol-atom ± 3.5	CeC2	298.15	experimental	emf	C–Ce	[1] Peng 2011 cites Anderson 2011	Table 2, p. 2, row 12 report
-27.2 kJ/mol-atom	CeC2	298.15	experimental	Knudsen cell MS	C–Ce	[1] Peng 2011 cites Winchell 1967 doi	Table 2, p. 2, row 10 report
-25.4 kJ/mol-atom ± 1.4	CeC2	298.15	experimental	Synthesis calorimetry	C–Ce	[1] Peng 2011 cites Meschel 1995 doi	Table 2, p. 2, row 11 report
-20.9 kJ/mol-atom ± 7	CeC2	298.15	experimental	Knudsen cell MS	C–Ce	[1] Peng 2011 cites Balducci 1969	Table 2, p. 2, row 9 report

Uncertainty budget

Components kept separate, in the value's unit (literature SCHEMA.md, UNCERTAINTY_CALIBRATION.md): effective = max(sqrt(max(printed, reading, method)^2 + composition^2 + conversion^2), scatter). The method floor is the robust between-study scatter of the method class in ORCHID (calibrated) or a documented prior; printed values and printed uncertainties are unchanged.

Uncertainty budget of the literature values of CeC2
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-40.03	kJ/mol-atom	3.7	0.005	4.2 (kems_vapour, calibrated)	4.2
-34.9	kJ/mol-atom		0.05	4.2 (kems_vapour, calibrated)	4.2
-32.4	kJ/mol-atom	1.8	0.05	1 (combustion_calorimetry, cleaned_below_threshold)	1.8
-31.3	kJ/mol-atom		0.05	4.1 (experimental_unspecified, cleaned_below_threshold)	4.1
-29.5	kJ/mol-atom	3.5	0.05	4.6 (emf, cleaned_below_threshold)	4.6
-27.2	kJ/mol-atom		0.05	4.2 (kems_vapour, calibrated)	4.2
-25.4	kJ/mol-atom	1.4	0.05	3.2 (solution_reaction_calorimetry, calibrated)	3.2
-20.9	kJ/mol-atom	7	0.05	4.2 (kems_vapour, calibrated)	7

DFT formation energies

Lowest-energy entries at this composition. Materials Project and OQMD use different energy references and are never averaged. 1 eV/atom = 96.485 kJ/mol-atom.

DFT formation energy of CeC2
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaaeff	-15.378	-0.159383	I4/mmm	5.1766	0.0537	no
OQMD	oqmd-13373	-8.01	-0.08302	I4/mmm	1.2254	0.0127	no

DFT sources: A. Jain et al., Commentary: The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002. doi:10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501-1509; S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010. doi:10.1007/s11837-013-0755-4 (CC BY 4.0);

Sources

Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). doi:10.1016/j.calphad.2011.09.002

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735943
R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736065

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); G. Kim, S. V. Meschel, P. Nash, W. Chen, Experimental formation enthalpies for intermetallic phases and other inorganic compounds, Scientific Data 4 (2017) 170162, https://doi.org/10.1038/sdata.2017.162; B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file. Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_dft_benchmark_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735943},
  url       = {https://doi.org/10.5281/zenodo.23735943},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}