GaN: enthalpy of formation

8 accepted literature formation-enthalpy value(s) (experimental 1, unspecified 7); experimental median -52.1 kJ/mol-atom (n = 1); Materials Project -63.373 kJ/mol-atom (mp-aaaaabey); OQMD -55.891 kJ/mol-atom (oqmd-6450).

Systems: Ga–N

Literature values

Enthalpy of formation of GaN reported in the literature (8)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-52.1 kJ/mol-atom ± 2	GaN	298.15	experimental	Combustion calorimetry	Ga–N	[1] Unland 2003 cites Hahn 1940 doi	Table 2, p. 3, row 1 report
-157.7 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Madar 1975	Table AI, p. 18, row 25 report
-157.7 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Karpinski 1984	Table AI, p. 18, row 26 report
-156.8 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Ranade 2000	Table AI, p. 18, row 27 report
-140.2 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites MacChesney 1970	Table AI, p. 18, row 30 report
-140 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Unland	Table AI, p. 18, row 17 report
-117.1 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Davydov 1999	Table AI, p. 18, row 18 report
-104.2 kJ/mol (basis unstated)	GaN	298.15	unspecified		Ga–N	[2] Onderka 2002 cites Hahn 1940	Table AI, p. 18, row 24 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 GaN
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-52.1	kJ/mol-atom	2	0.025	1 (combustion_calorimetry, cleaned_below_threshold)	2
-157.7	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-157.7	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-156.8	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-140.2	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-140	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-117.1	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7
-104.2	kJ/mol (basis unstated)		0.05	7 (unknown, calibrated)	7

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 GaN
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaabey	-63.373	-0.656817	P6_3mc	0	0	no
OQMD	oqmd-6450	-55.891	-0.57927	P63mc	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

J. Unland, B. Onderka, A. Davydov, R. Schmid-Fetzer, Thermodynamics and Phase Stability in the Ga–N System, Journal of Crystal Growth 256, 33-51 (2003). doi:10.1016/s0022-0248(03)01352-6
B. Onderka, J. Unland, R. Schmid-Fetzer, Thermodynamics and phase stability in the In–N system, J. Mater. Res. 17, 3065-3083 (2002). doi:10.1557/jmr.2002.0445

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}
}