MgO: enthalpy of formation

5 accepted literature formation-enthalpy value(s) (experimental 1, model 1, DFT 3); Materials Project -294.608 kJ/mol-atom (mp-aaaaabwr); OQMD -284.268 kJ/mol-atom (oqmd-1443261).

Systems: Mg–O

Literature values

Enthalpy of formation of MgO reported in the literature (5)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location	Quote
-602 kJ/(mol 0)	MgO	298.15	experimental		Mg–O	[1] Hallstedt 1993 cites Fikner	p. 5 report	However, Fikner [5J and Otsuka and Kozuka [6J have found correlations between the enthalpy and entropy of dissolution of 0 into liquid metals and the enthalpy of formation of the oxide at 298 K. Using the expressions provided by Fitzner I5J with the enthalpy of formation of MgO (A?&s = -602 kJ/(mol 0)) gives A"G = -500000 + 90T J/mol for dissolution of 0 in liquid Mg (1 mol-W standard state).
-300.62 kJ/mol-atom	MgO		model		Mg–O	[2] Li 2023	Table 5, p. 6, row 1 report
-282.82 kJ/mol-atom	MgO		DFT	first-principle method	Mg–O	[2] Li 2023	Table 3, p. 5, row 2 report
-281.86 kJ/mol-atom	MgO	0	DFT	first-principle method	Mg–O	[2] Li 2023	Table 3, p. 5, row 1 report
-263.71 kJ/mol-atom	MgO		DFT	first-principle method	Mg–O	[2] Li 2023	Table 3, p. 5, row 3 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 MgO
Value	Unit	Reading	Method (class, basis)	Effective
-602	kJ/(mol 0)	0.05	7 (unknown, calibrated)	7
-300.62	kJ/mol-atom	0.005	3.9 (model_calculated, calibrated)	3.9
-282.82	kJ/mol-atom	0.005	9.966 (dft, calibrated)	9.966
-281.86	kJ/mol-atom	0.005	9.966 (dft, calibrated)	9.966
-263.71	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 MgO
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaabwr	-294.608	-3.0534	Fm-3m	0	0	no
OQMD	oqmd-1443261	-284.268	-2.94624	P21/c	0	0	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

Bengt Hallstedt, The Magnesium — Oxygen system, Calphad 17, 281-286 (1993). doi:10.1016/0364-5916(93)90006-w
X.-J. Li, S.-H. Liu, Thermodynamic description of the Mg-O and Al-O systems, J min metall B Metall 59, 395-405 (2023). doi:10.2298/jmmb230621034l

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}
}