Nb7Ni6: enthalpy of formation

10 accepted literature formation-enthalpy value(s) (experimental 4, model 1, DFT 5); experimental median -22.735 kJ/mol-atom (n = 4); Materials Project -19.894 kJ/mol-atom (mp-aaackvmr); OQMD -19.955 kJ/mol-atom (oqmd-30782).

Systems: Nb–Ni

Literature values

Enthalpy of formation of Nb7Ni6 reported in the literature (10)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-23 kJ/mol-atom	Nb7Ni6	298.15	experimental	Experimental	Nb–Ni	[1] Santhy 2015 cites Hultgren 1973	Table 6, p. 4, row 3 report
-23 kJ/mol-atom ± 3	Nb7Ni6	600.15	experimental	Experimental	Nb–Ni	[1] Santhy 2015 cites Kubaschewski 2015	Table 6, p. 4, row 2 report
-22.47 kJ/mol-atom ± 2.2	Nb7Ni6	298.15	experimental	Experimental	Nb–Ni	[1] Santhy 2015 cites Argent 1959	Table 6, p. 4, row 1 report
-22.45 kJ/mol-atom	μ-Nb7Ni6 + µ-Nb7Ni6	298.15	experimental		Nb–Ni	[2] Sun 2023 cites Argent 1959	Table 6, p. 33, row 5 report
-20.76 kJ/mol-atom	Nb7Ni6	298.15	model	Miedema	Nb–Ni	[1] Santhy 2015 cites Niessen 1988 doi	Table 6, p. 4, row 4 report
-22.5 kJ/mol-atom	Nb7Ni6	0	DFT	First-principle	Nb–Ni	[1] Santhy 2015	Table 6, p. 4, row 5 report
-20.63 kJ/mol-atom	μ-Nb7Ni6 + µ-Nb7Ni6	0	DFT	DFT and phonon calculations	Nb–Ni	[2] Sun 2023	Table 6, p. 33, row 3 report
-20.5 kJ/mol-atom	μ-Nb7Ni6 + µ-Nb7Ni6	0	DFT	DFT and phonon calculations	Nb–Ni	[2] Sun 2023	Table 6, p. 33, row 4 report
-20.43 kJ/mol-atom	μ-Nb7Ni6 + µ-Nb7Ni6	298.15	DFT	DFT and phonon calculations	Nb–Ni	[2] Sun 2023	Table 6, p. 33, row 4 report
-20.38 kJ/mol-atom	μ-Nb7Ni6 + µ-Nb7Ni6	298.15	DFT	DFT and phonon calculations	Nb–Ni	[2] Sun 2023	Table 6, p. 33, 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 Nb7Ni6
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-23	kJ/mol-atom		0.5	4.1 (experimental_unspecified, cleaned_below_threshold)	4.1
-23	kJ/mol-atom	3	0.5	4.1 (experimental_unspecified, cleaned_below_threshold)	4.1
-22.47	kJ/mol-atom	2.2	0.005	4.1 (experimental_unspecified, cleaned_below_threshold)	4.1
-22.45	kJ/mol-atom		0.005	3.5 (unknown, calibrated)	3.5
-20.76	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-22.5	kJ/mol-atom		0.05	3.929 (dft, calibrated)	3.929
-20.63	kJ/mol-atom		0.005	3.929 (dft, calibrated)	3.929
-20.5	kJ/mol-atom		0.05	3.929 (dft, calibrated)	3.929
-20.43	kJ/mol-atom		0.005	3.929 (dft, calibrated)	3.929
-20.38	kJ/mol-atom		0.005	3.929 (dft, calibrated)	3.929

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 Nb7Ni6
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaackvmr	-19.894	-0.206183	R-3m	0	0	no
OQMD	oqmd-30782	-19.955	-0.206825	R-3m	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

K. Santhy, K.C. Hari Kumar, Thermodynamic reassessment of Nb-Ni-Ti system with order–disorder model, Journal of Alloys and Compounds 619, 733-747 (2015). doi:10.1016/j.jallcom.2014.08.200
Hui Sun, Shun-Li Shang, Rushi Gong, Brandon J. Bocklund, Allison M. Beese, Zi-Kui Liu, Thermodynamic modeling of the Nb-Ni system with uncertainty quantification using PyCalphad and ESPEI, Calphad 82, 102563 (2023). doi:10.1016/j.calphad.2023.102563

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}
}