Mg3Sb2: enthalpy of formation

16 accepted literature formation-enthalpy value(s) (experimental 4, model 12); experimental median -47 kJ/mol-atom (n = 1); Materials Project -43.056 kJ/mol-atom (mp-aaacqblj); OQMD -36.528 kJ/mol-atom (oqmd-116230).

Systems: Mg–Sb

Literature values

Enthalpy of formation of Mg3Sb2 reported in the literature (16)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-299 kJ/mol (basis unstated) ± 3	α-Mg3Sb2	900	experimental	emf measurements	Mg–Sb	[1] Balakumar 2005 cites Rao 1971	Table 8, p. 9, row 1 report
-285 kJ/mol (basis unstated)	α-Mg3Sb2	923	experimental	high temperature calorimetric measurements	Mg–Sb	[1] Balakumar 2005 cites Kubaschewski 1939	Table 8, p. 9, row 3 report
-235 kJ/mol (basis unstated) ± 6	α-Mg3Sb2	773	experimental	emf measurements	Mg–Sb	[1] Balakumar 2005 cites Eremenko 1964	Table 8, p. 9, row 2 report
-47 kJ/mol-atom ± 1.2	Mg3Sb2	773	experimental		Mg–Sb	[2] Jönsson 1987 cites Eremenko 1964	Table 1I, p. 4, row 6 report
-490 kJ/mol (basis unstated)	α-Mg3Sb2	298.15	model		Mg–Sb	[1] Balakumar 2005	Table 8, p. 9, row 6 report
-320 kJ/mol (basis unstated) ± 40	α-Mg3Sb2	800	model		Mg–Sb	[1] Balakumar 2005 cites Hultgren 1973	Table 8, p. 9, row 4 report
-300 kJ/mol (basis unstated)	α-Mg3Sb2	298.15	model		Mg–Sb	[1] Balakumar 2005 cites Barin 1977	Table 8, p. 9, row 5 report
-64 kJ/mol-atom ± 8	Mg3Sb2	800	model		Mg–Sb	[2] Jönsson 1987 cites Hultgren 1973	Table 1I, p. 4, row 8 report
-60 kJ/mol-atom	Mg3Sb2	298.15	model		Mg–Sb	[2] Jönsson 1987 cites Barin 1977 doi	Table 1I, p. 4, row 2 report
-59.8 kJ/mol-atom ± 0.6	Mg3Sb2	900	model		Mg–Sb	[2] Jönsson 1987 cites Rao 1971	Table 1I, p. 4, row 10 report
-57 kJ/mol-atom	Mg3Sb2	923	model		Mg–Sb	[2] Jönsson 1987 cites Kubaschewski 1939	Table 1I, p. 4, row 12 report
-55.2 kJ/mol-atom	Mg3Sb2	298.15	model		Mg–Sb	[2] Jönsson 1987	Table 1I, p. 4, row 1 report
-53.2 kJ/mol-atom	Mg3Sb2	773	model		Mg–Sb	[2] Jönsson 1987	Table 1I, p. 4, row 5 report
-53.2 kJ/mol-atom	Mg3Sb2	800	model		Mg–Sb	[2] Jönsson 1987	Table 1I, p. 4, row 7 report
-52.6 kJ/mol-atom	Mg3Sb2	900	model		Mg–Sb	[2] Jönsson 1987	Table 1I, p. 4, row 9 report
-52.4 kJ/mol-atom	Mg3Sb2	923	model		Mg–Sb	[2] Jönsson 1987	Table 1I, p. 4, row 11 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 Mg3Sb2
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-299	kJ/mol (basis unstated)	3	0.5	23 (emf, cleaned_below_threshold)	23
-285	kJ/mol (basis unstated)		0.5	16 (solution_reaction_calorimetry, calibrated)	16
-235	kJ/mol (basis unstated)	6	0.5	23 (emf, cleaned_below_threshold)	23
-47	kJ/mol-atom	1.2	0.01	3.5 (unknown, calibrated)	3.5
-490	kJ/mol (basis unstated)		0.5	19.5 (model_calculated, calibrated)	19.5
-320	kJ/mol (basis unstated)	40	0.5	19.5 (model_calculated, calibrated)	40
-300	kJ/mol (basis unstated)		0.5	19.5 (model_calculated, calibrated)	19.5
-64	kJ/mol-atom	8	0.1	3.9 (model_calculated, calibrated)	8
-60	kJ/mol-atom		0.01	3.9 (model_calculated, calibrated)	3.9
-59.8	kJ/mol-atom	0.6	0.1	3.9 (model_calculated, calibrated)	3.9
-57	kJ/mol-atom		0.01	3.9 (model_calculated, calibrated)	3.9
-55.2	kJ/mol-atom		0.01	3.9 (model_calculated, calibrated)	3.9
-53.2	kJ/mol-atom		0.1	3.9 (model_calculated, calibrated)	3.9
-53.2	kJ/mol-atom		0.1	3.9 (model_calculated, calibrated)	3.9
-52.6	kJ/mol-atom		0.01	3.9 (model_calculated, calibrated)	3.9
-52.4	kJ/mol-atom		0.01	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 Mg3Sb2
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaacqblj	-43.056	-0.446245	Ia-3	0	0	yes
OQMD	oqmd-116230	-36.528	-0.378584	Ia-3	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

T. Balakumar, M. Medraj, Thermodynamic modeling of the Mg–Al–Sb system, Calphad 29, 24-36 (2005). doi:10.1016/j.calphad.2005.03.001
Björn Jönsson, John Ågren, A theoretical evaluation of chemical ordering and glass transition in liquid Mg-Sb alloys, Metall Trans A 18, 1395-1401 (1987). doi:10.1007/bf02646653

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}
}