Ga2Gd: enthalpy of formation

8 accepted literature formation-enthalpy value(s) (experimental 4, model 4); experimental median -72.8 kJ/mol-atom (n = 4); Materials Project -63.164 kJ/mol-atom (mp-aaaabdgn); OQMD -64.461 kJ/mol-atom (oqmd-91491).

Systems: Ga–Gd

Literature values

Enthalpy of formation of Ga2Gd reported in the literature (8)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location	Quote
-83.5 kJ/mol-atom	Ga2Gd	298.15	experimental		Ga–Gd	[1] Boukideur 2020 cites Bayanov 1975	Table 4, p. 4, row 5 report
-72.8 kJ/mol-atom ± 2.8	Ga2Gd	1373	experimental	Calorimetry	Ga–Gd	[2] Tamim 2023 cites Meschel 2001 doi	Table 2, p. 8, row 20 report
-72.8 kJ/mol-atom	Ga2Gd	298.15	experimental		Ga–Gd	[1] Boukideur 2020 cites Meschel 2001 doi	Table 4, p. 4, row 4 report
-65.03 kJ/mol-atom ± 1	Ga2Gd	298.15	experimental	EMF	Ga–Gd	[2] Tamim 2023 cites Bayanov 1975	Table 2, p. 8, row 21 report
-261.5 unspecified ± 5.9	Ga2Gd	823.15	model		Ga–Gd	[3] Liu 2019 cites Kober 1983	p. 4 report	The enthalpy, entropy, and Gibbs energy of formation of Ga2Gd from liquid Ga and solid Gd at 550 °C were as: - 261.5 ± 5.9 kJ/mol, - 88.3 ± 7.1 J/mol, and - 189.0 ± 0.4 kJ/mol [42], respectively, which was cited from Ref. [17].
-72.8 kJ/mol-atom	Ga2Gd		model		Ga–Gd	[1] Boukideur 2020	Table 4, p. 4, row 6 report
-65.03 kJ/mol-atom	Ga2Gd		model	Emf (723–923 K) optimization	Ga–Gd	[1] Boukideur 2020 cites De 2014	Table 4, p. 4, row 3 report
-63.156 kJ/mol-atom	Ga2Gd	298.15	model		Ga–Gd	[2] Tamim 2023	Table 2, p. 8, row 22 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 Ga2Gd
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-83.5	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-72.8	kJ/mol-atom	2.8	0.05	3.2 (solution_reaction_calorimetry, calibrated)	3.2
-72.8	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-65.03	kJ/mol-atom	1	0.005	4.6 (emf, cleaned_below_threshold)	4.6
-261.5	unspecified	5.9	0.05	unit 'unspecified' not convertible to kJ/mol-atom	5.9
-72.8	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
-65.03	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-63.156	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9

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 Ga2Gd
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaabdgn	-63.164	-0.654654	P6/mmm	0	0	no
OQMD	oqmd-91491	-64.461	-0.668099	P6/mmm	0	0	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

M. AiT Boukideur, N. Selhaoui, F.Z. chrifi Alaoui, A. Iddaoudi, K. Achgar, Thermodynamic modeling of the Ga-Gd binary system, Materials Today: Proceedings 24, 71-75 (2020). doi:10.1016/j.matpr.2019.07.598
Rkia Tamim, Olivier Rapaud, Rémy Boulesteix, Alexandre Maître, Thermodynamic assessment of the Ga–Gd, Ga–Nb and Gd–Nb binary phase diagrams towards the Ga–Gd–Nb system, Calphad 82, 102596 (2023). doi:10.1016/j.calphad.2023.102596
Jinming Liu, Fei Li, Jinping Liu, Xu Zhang, Tahir Ahmad, Tongxiang Liang, Thermodynamic description of the Ce–Ga and Ga–Gd systems, Monatsh Chem 150, 1225-1233 (2019). doi:10.1007/s00706-019-02420-8

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}
}