HfC: enthalpy of formation

6 accepted literature formation-enthalpy value(s) (experimental 5, model 1).

Systems: C–Hf

Literature values

Enthalpy of formation of HfC reported in the literature (6)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location	Quote
-262.7 kJ/mol (basis unstated)	HfC	298.15	experimental	Langmuir method	C–Hf	[1] Bittermann 1997 cites Coffman 1963	Table 3, p. 3, row 1 report
-231.1 kJ/mol (basis unstated) ± 2.1	HfC1.00	298.15	experimental	Combustion calorimetry	C–Hf	[1] Bittermann 1997 cites Zehlankin 1964	Table 3, p. 3, row 4 report
-210.5 kJ/mol (basis unstated) ± 20.9	HfC	298.15	experimental	Langmuir method	C–Hf	[1] Bittermann 1997 cites Fesenko 1966	Table 3, p. 3, row 5 report
-209.4 kJ/mol (basis unstated)	HfC1.0	298.15	experimental	Combustion calorimetry of Hf oxycarbides	C–Hf	[1] Bittermann 1997 cites ref. 77Kor	Table 3, p. 3, row 6 report
-209.4 kJ/mol (basis unstated)	HfC	298.15	experimental		C–Hf	[1] Bittermann 1997 cites ref. 77Kor	p. 7 report	Thus, the value Ae/-/(HfC, 298 K) = -209.4 kJ/mol from [77Kor] was selected in the present assessment, which was also confirmed by the calculation of the phase relations in the ternary Hf-B-C system [97Bit].
-209.4 kJ/mol (basis unstated)	HfC	298.15	model		C–Hf	[1] Bittermann 1997	Table 3, p. 3, 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 HfC
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-262.7	kJ/mol (basis unstated)		0.05	8.4 (kems_vapour, calibrated)	8.4
-231.1	kJ/mol (basis unstated)	2.1	0.05	2 (combustion_calorimetry, cleaned_below_threshold)	2.1
-210.5	kJ/mol (basis unstated)	20.9	0.05	8.4 (kems_vapour, calibrated)	20.9
-209.4	kJ/mol (basis unstated)		0.05	2 (combustion_calorimetry, cleaned_below_threshold)	2
-209.4	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-209.4	kJ/mol (basis unstated)		0.05	7.8 (model_calculated, calibrated)	7.8

Sources

H. Bittermann, P. Rogl, Critical assessment and thermodynamic calculation of the binary system hafnium-carbon (Hf-C), JPE 18, 344-356 (1997). doi:10.1007/s11669-997-0061-3

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}
}