Fe2Gd: enthalpy of formation

14 accepted literature formation-enthalpy value(s) (experimental 6, model 8); experimental median -7.55 kJ/mol-atom (n = 4); Materials Project 1.566 kJ/mol-atom (mp-aaaabdsr); OQMD -3.181 kJ/mol-atom (oqmd-18836).

Systems: Fe–Gd

Literature values

Enthalpy of formation of Fe2Gd reported in the literature (14)
Value	Phase as printed	T (K)	Class	System	Source	Location
-11.6 kJ/mol-atom ± 2	Fe2Gd	298.15	experimental	Fe–Gd	[1] Zinkevich 2002 cites Colinet 1987	Table 12, p. 13, row 9 report
-11.6 per mol-atom ± 2	Fe2Gd	298.15	experimental	Fe–Gd	[1] Zinkevich 2002 cites Colinet 1987	Table 12, p. 13, row 9 report
-11.6 kJ/mol-atom ± 2	Fe2Gd	298.15	experimental	Fe–Gd	[2] Zinkevich 2000 cites Colinet 1987 doi	Table 2, p. 3, row 2 report
-3.5 kJ/mol-atom ± 1.5	Fe2Gd	1078	experimental	Fe–Gd	[1] Zinkevich 2002 cites Deodhar 1975	Table 12, p. 13, row 12 report
-3.5 per mol-atom ± 1.5	Fe2Gd	1078	experimental	Fe–Gd	[1] Zinkevich 2002 cites Deodhar 1975	Table 12, p. 13, row 12 report
-3.5 kJ/mol-atom ± 1.5	Fe2Gd	1078	experimental	Fe–Gd	[2] Zinkevich 2000 cites Deodhar 1975	Table 2, p. 3, row 1 report
-6.81 kJ/mol-atom	Fe2Gd	1078	model	Fe–Gd	[1] Zinkevich 2002	Table 12, p. 13, row 14 report
-6.81 per mol-atom	Fe2Gd	1078	model	Fe–Gd	[1] Zinkevich 2002	Table 12, p. 13, row 14 report
-5.94 per mol-atom	Fe2Gd	298.15	model	Fe–Gd	[1] Zinkevich 2002	Table 12, p. 13, row 11 report
-5.94 kJ/mol-atom	Fe2Gd	298.15	model	Fe–Gd	[1] Zinkevich 2002	Table 12, p. 13, row 11 report
-4.59 kJ/mol-atom	Fe2Gd	298.15	model	Fe–Gd	[1] Zinkevich 2002 cites Zinkevich 2000	Table 12, p. 13, row 10 report
-4.59 per mol-atom	Fe2Gd	298.15	model	Fe–Gd	[1] Zinkevich 2002 cites Zinkevich 2000	Table 12, p. 13, row 10 report
-4.38 kJ/mol-atom	Fe2Gd	1078	model	Fe–Gd	[1] Zinkevich 2002 cites Zinkevich 2000	Table 12, p. 13, row 13 report
-4.38 per mol-atom	Fe2Gd	1078	model	Fe–Gd	[1] Zinkevich 2002 cites Zinkevich 2000	Table 12, p. 13, row 13 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 Fe2Gd
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-11.6	kJ/mol-atom	2	0.05	3.5 (unknown, calibrated)	3.5
-11.6	per mol-atom	2	0.05	unit 'per mol-atom' not convertible to kJ/mol-atom	2
-11.6	kJ/mol-atom	2	5.000e-4	3.5 (unknown, calibrated)	3.5
-3.5	kJ/mol-atom	1.5	0.05	3.5 (unknown, calibrated)	3.5
-3.5	per mol-atom	1.5	0.05	unit 'per mol-atom' not convertible to kJ/mol-atom	1.5
-3.5	kJ/mol-atom	1.5	5.000e-4	3.5 (unknown, calibrated)	3.5
-6.81	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-6.81	per mol-atom		0.005	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-5.94	per mol-atom		0.005	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-5.94	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-4.59	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-4.59	per mol-atom		0.005	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-4.38	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-4.38	per mol-atom		0.005	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom

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 Fe2Gd
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaabdsr	1.566	0.016234	Fd-3m	1.9773	0.0205	no
OQMD	oqmd-18836	-3.181	-0.032969	Fd-3m	0.0306	3.000e-4	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

Matvei Zinkevich, Norbert Mattern, Hans‐Jürgen Seifert, Eberhard Gmelin, A thermodynamic assessment of the Fe‐Gd‐Mo system, Scand Jof Metallurgy 31, 34-51 (2002). doi:10.1034/j.1600-0692.2002.311310106.x
M. Zinkevich, N. Mattern, H. J. Seifert, Reassessment of the Fe-Gd (Iron-Gadolinum) system, JPE 21, 385-394 (2000). doi:10.1361/105497100770339923

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}
}