YC2: enthalpy of formation

13 accepted literature formation-enthalpy value(s) (experimental 8, model 4, DFT 1); experimental median -36.35 kJ/mol-atom (n = 4); Materials Project -18.127 kJ/mol-atom (mp-aaaaaamb); OQMD -24.068 kJ/mol-atom (oqmd-2037974).

Systems: C–Y

Literature values

Enthalpy of formation of YC2 reported in the literature (13)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-38.8 kJ/mol (basis unstated)	YC2	298.15	experimental		C–Y	[1] Gröbner 1995 cites Storms 1971	Table 3, p. 3, row 9 report
-38.8 kJ/mol-atom	YC2	298.15	experimental		C–Y	[2] Xu 2019 cites Storms 1971	Table 2, p. 3, row 25 report
-37.7 kJ/mol-atom ± 8.4	YC2	298.15	experimental		C–Y	[2] Xu 2019 cites De 1965 doi	Table 2, p. 3, row 23 report
-37.7 kJ/mol (basis unstated) ± 8.4	YC2	298.15	experimental		C–Y	[1] Gröbner 1995 cites De 1965 doi	Table 3, p. 3, row 7 report
-35 kJ/mol (basis unstated) ± 3.5	YC2	298.15	experimental		C–Y	[1] Gröbner 1995 cites Anderson 1972	Table 3, p. 3, row 10 report
-35 kJ/mol-atom ± 3.5	YC2	298.15	experimental		C–Y	[2] Xu 2019 cites Anderson 1972	Table 2, p. 3, row 26 report
-30.3 kJ/mol (basis unstated) ± 5.7	YC2	298.15	experimental		C–Y	[1] Gröbner 1995 cites Kohl 1970 doi	Table 3, p. 3, row 8 report
-30.3 kJ/mol-atom ± 5.7	YC2	298.15	experimental		C–Y	[2] Xu 2019 cites Kohl 1970 doi	Table 2, p. 3, row 24 report
-64 kJ/mol-atom	YC2		model		C–Y	[2] Xu 2019 cites Niessen 1981 doi	Table 2, p. 3, row 28 report
-36.5 kJ/mol (basis unstated)	YC2		model		C–Y	[1] Gröbner 1995	Table 3, p. 3, row 12 report
-36.5 kJ/mol-atom	YC2		model		C–Y	[2] Xu 2019 cites Grobner 1995 doi	Table 2, p. 3, row 27 report
-34.17 kJ/mol-atom	YC2		model	CALPHAD	C–Y	[2] Xu 2019	Table 3, p. 3, row 16 report
-29.16 kJ/mol-atom	YC2	0	DFT	First principles	C–Y	[2] Xu 2019	Table 3, p. 3, row 15 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 YC2
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-38.8	kJ/mol (basis unstated)		0.05	10.5 (unknown, calibrated)	10.5
-38.8	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-37.7	kJ/mol-atom	8.4	0.05	3.5 (unknown, calibrated)	8.4
-37.7	kJ/mol (basis unstated)	8.4	0.05	10.5 (unknown, calibrated)	10.5
-35	kJ/mol (basis unstated)	3.5	0.05	10.5 (unknown, calibrated)	10.5
-35	kJ/mol-atom	3.5	0.5	3.5 (unknown, calibrated)	3.5
-30.3	kJ/mol (basis unstated)	5.7	0.05	10.5 (unknown, calibrated)	10.5
-30.3	kJ/mol-atom	5.7	0.05	3.5 (unknown, calibrated)	5.7
-64	kJ/mol-atom		0.5	3.9 (model_calculated, calibrated)	3.9
-36.5	kJ/mol (basis unstated)		0.05	11.7 (model_calculated, calibrated)	11.7
-36.5	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
-34.17	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-29.16	kJ/mol-atom		0.005	9.966 (dft, calibrated)	9.966

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 YC2
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaaamb	-18.127	-0.187877	I4/mmm	6.6114	0.0685	no
OQMD	oqmd-2037974	-24.068	-0.249444	C2/m	1.2734	0.0132	yes

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

J. Gröbner, H.-L. Lukas, F. Aldinger, Thermodynamic calculations in the YAlC system, Journal of Alloys and Compounds 220, 8-14 (1995). doi:10.1016/0925-8388(94)06028-2
Kai Xu, Houke Zou, Keke Chang, Zixuan Deng, Xiaobing Zhou, Yeyan Huang et al., Thermodynamic description of the sintering aid system in silicon carbide ceramics with the addition of yttrium, Journal of the European Ceramic Society 39, 4510-4519 (2019). doi:10.1016/j.jeurceramsoc.2019.07.012

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}
}