Nb3Sn: enthalpy of formation

21 accepted literature formation-enthalpy value(s) (experimental 10, model 11); Materials Project -15.81 kJ/mol-atom (mp-aaaaabza); OQMD -18.84 kJ/mol-atom (oqmd-17754).

Systems: Nb–Sn

Literature values

Enthalpy of formation of Nb3Sn reported in the literature (21)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location	Quote
-32.06 kJ/mol (basis unstated) ± 1.97	Nb3Sn	860	experimental	Electromotive force	Nb–Sn	[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 1 report
-32.06 kJ/mol (basis unstated) ± 1.97	Nb3Sn	860	experimental	Electromotive Force	Nb–Sn	[2] Toffolon 1998 cites ref. 75Mal	Table 1, p. 1, row 1 report
-32.06 kJ/mol (basis unstated) ± 1.97	Nb3Sn	860	experimental	Electromotive force	Nb–Sn	[1] Toffolon 2002 cites Malets 1975	Table 1, p. 1, row 2 report
-16.7 unspecified ± 1.8	Nb3Sn	1623.15	experimental		Nb–Sn	[1] Toffolon 2002	p. 3 report	Five experiments were carried out, and the average value of the enthalpy of formation of Nb3Sn at 1350 °C was equal to -16.7 ± 1.8 kJ/mol.
-16.7 kJ/mol (basis unstated) ± 1.8	Nb3Sn	1623	experimental	Drop calorimetry	Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 6 report
-16.57 kJ/mol (basis unstated)	Nb3Sn	298.15	experimental	Vapor pressure (second law)	Nb–Sn	[1] Toffolon 2002 cites Schiffman 1982	Table 1, p. 1, row 3 report
-16.57 kJ/mol (basis unstated)	Nb3Sn	298.15	experimental	Vapor pressure (second law)	Nb–Sn	[2] Toffolon 1998 cites ref. 82Sch	Table 1, p. 1, row 2 report
-16.19 kJ/mol (basis unstated)	Nb3Sn	298.15	experimental	Vapor pressure (third law)	Nb–Sn	[1] Toffolon 2002 cites Schiffman 1982	Table 1, p. 1, row 4 report
-16.19 kJ/mol (basis unstated)	Nb3Sn	298.15	experimental	Vapor pressure (third law)	Nb–Sn	[2] Toffolon 1998 cites ref. 82Sch	Table 1, p. 1, row 3 report
-15.2 kJ/mol (basis unstated) ± 2.3	Nb3Sn	1473	experimental	Drop calorimetry	Nb–Sn	[1] Toffolon 2002 cites Meschel 1998 doi	Table 1, p. 1, row 5 report
-18.307 kJ/mol-atom	Nb3Sn	860	model		Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 11 report
-18.241 kJ/mol-atom	Nb3Sn	1273	model		Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 12 report
-17.876 kJ/mol-atom	Nb3Sn	1473	model		Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 13 report
-17.095 kJ/mol-atom	Nb3Sn	1623	model		Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 14 report
-16.564 kJ/mol-atom	Nb3Sn	298.15	model		Nb–Sn	[1] Toffolon 2002	Table 1, p. 1, row 10 report
-16.4 kJ/mol-atom	Nb3Sn	298.15	model		Nb–Sn	[1] Toffolon 2002 cites Miedema 1980 doi	Table 1, p. 1, row 7 report
-16.4 kJ/mol (basis unstated)	Nb3Sn	298.15	model	Calculation	Nb–Sn	[2] Toffolon 1998 cites ref. 80Mie	Table 1, p. 1, row 4 report
-16 kJ/mol (basis unstated)	Nb3Sn	298.15	model	Calculation	Nb–Sn	[2] Toffolon 1998 cites ref. 88Deb	Table 1, p. 1, row 5 report
-16 kJ/mol-atom	Nb3Sn	298.15	model		Nb–Sn	[1] Toffolon 2002 cites ref. 1988Deb	Table 1, p. 1, row 8 report
2.768 kJ/mol (basis unstated)	Nb3Sn	1273	model	Optimization	Nb–Sn	[2] Toffolon 1998	Table 1, p. 1, row 6 report
2.768 kJ/mol-atom	Nb3Sn	1273	model		Nb–Sn	[1] Toffolon 2002 cites Toffolon 2002	Table 1, p. 1, row 9 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 Nb3Sn
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-32.06	kJ/mol (basis unstated)	1.97	0.005	18.4 (emf, cleaned_below_threshold)	18.4
-32.06	kJ/mol (basis unstated)	1.97	5.000e-4	18.4 (emf, cleaned_below_threshold)	18.4
-32.06	kJ/mol (basis unstated)	1.97	0.005	18.4 (emf, cleaned_below_threshold)	18.4
-16.7	unspecified	1.8	0.05	unit 'unspecified' not convertible to kJ/mol-atom	1.8
-16.7	kJ/mol (basis unstated)	1.8	0.05	12.8 (solution_reaction_calorimetry, calibrated)	12.8
-16.57	kJ/mol (basis unstated)		0.005	12 (kems_vapour_second_law, prior)	12
-16.57	kJ/mol (basis unstated)		5.000e-4	12 (kems_vapour_second_law, prior)	12
-16.19	kJ/mol (basis unstated)		0.005	8 (kems_vapour_third_law, prior)	8
-16.19	kJ/mol (basis unstated)		5.000e-4	8 (kems_vapour_third_law, prior)	8
-15.2	kJ/mol (basis unstated)	2.3	0.05	12.8 (solution_reaction_calorimetry, calibrated)	12.8
-18.307	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-18.241	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-17.876	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-17.095	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-16.564	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-16.4	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
-16.4	kJ/mol (basis unstated)		5.000e-4	15.6 (model_calculated, calibrated)	15.6
-16	kJ/mol (basis unstated)		5.000e-4	15.6 (model_calculated, calibrated)	15.6
-16	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
2.768	kJ/mol (basis unstated)		5.000e-4	15.6 (model_calculated, calibrated)	15.6
2.768	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 Nb3Sn
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaabza	-15.81	-0.163862	Pm-3n	0	0	no
OQMD	oqmd-17754	-18.84	-0.195267	Pm-3n	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

C. Toffolon, C. Servant, J. C. Gachon, B. Sundman, Reassessment of the Nb-Sn system, JPE 23, 134-139 (2002). doi:10.1361/1054971023604071
C. Toffolon, C. Servant, B. Sundman, Thermodynamic assessment of the Nb-Sn system, JPE 19, 479-485 (1998). doi:10.1361/105497198770341978

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}
}