Ho2Ni17: enthalpy of formation

5 accepted literature formation-enthalpy value(s) (experimental 1, model 4); experimental median -23.1 kJ/mol-atom (n = 1); Materials Project -19.799 kJ/mol-atom (mp-aaacqkjz); OQMD -20.143 kJ/mol-atom (oqmd-30551).

Systems: Ho–Ni

Literature values

Enthalpy of formation of Ho2Ni17 reported in the literature (5)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-23.1 kJ/mol-atom ± 0.3	Ho2Ni17	650	experimental	EMF	Ho–Ni	[1] Kardellass 2015 cites Gozzi 2005 doi	Table 3, p. 4, row 32 report
-21.33 kJ/mol-atom	Ho2Ni17	298.15	model	Optimization	Ho–Ni	[1] Kardellass 2015	Table 3, p. 4, row 33 report
-21.33 kJ/mol-atom	Ni17Ho2	298.15	model	Optimization	Ho–Ni	[2] Kardellass 2016 cites Kardellass 2015 doi	Table 4, p. 7, row 2 report
-16 kJ/mol-atom	Ho2Ni17	298.15	model	Calculation	Ho–Ni	[1] Kardellass 2015 cites Kayzel 1995	Table 3, p. 4, row 34 report
-16 kJ/mol-atom	Ho2Ni17	298.15	model	Prediction	Ho–Ni	[1] Kardellass 2015 cites de Boer FR 1989	Table 3, p. 4, row 31 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 Ho2Ni17
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-23.1	kJ/mol-atom	0.3	0.05	4.6 (emf, cleaned_below_threshold)	4.6
-21.33	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-21.33	kJ/mol-atom		0.005	3.9 (model_calculated, calibrated)	3.9
-16	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
-16	kJ/mol-atom		0.05	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 Ho2Ni17
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaacqkjz	-19.799	-0.205208	P6_3/mmc	0.498	0.0052	no
OQMD	oqmd-30551	-20.143	-0.208772	P63/mmc	0.527	0.0055	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

S. Kardellass, C. Servant, N. Selhaoui, Thermodynamic description of the holmium–nickel system, J Therm Anal Calorim 119, 1225-1234 (2015). doi:10.1007/s10973-014-4189-1
Saïd Kardellass, Colette Servant, Najim Selhaoui, Thermodynamic description of the Ni–Yb and Ni–Eu binary systems, J Therm Anal Calorim 125, 255-269 (2016). doi:10.1007/s10973-016-5380-3

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}
}