CoZr2: enthalpy of formation

12 accepted literature formation-enthalpy value(s) (experimental 5, model 7); experimental median -29.7 kJ/mol-atom (n = 2); Materials Project -24.825 kJ/mol-atom (mp-aaaaaaye); OQMD -25.161 kJ/mol-atom (oqmd-29534).

Systems: Co–Zr

Literature values

Enthalpy of formation of CoZr2 reported in the literature (12)
Value	Phase as printed	T (K)	Class	System	Source	Location
-33 kJ/mol-atom ± 2	CoZr2	1290	experimental	Co–Zr	[1] Durga 2010 cites Gachon 1983 doi	Table 5, p. 5, row 33 report
-33 per mol-atom ± 2000	CoZr2	1290	experimental	Co–Zr	[2] Zhou 2021 cites Gachon 1983 doi	Table 3, p. 5, row 19 report
-26.4 per mol-atom ± 1000	CoZr2	298.15	experimental	Co–Zr	[2] Zhou 2021 cites Guo 1998 doi	Table 3, p. 5, row 20 report
-26.4 kJ/mol-atom	CoZr2	298.15	experimental	Co–Zr	[3] Bratberg 2006 cites Binary 1986	Table 6, p. 5, row 7 report
-26.3 per mol-atom	CoZr2	298.15	experimental	Co–Zr	[2] Zhou 2021 cites Ohodnicki 2008 doi	Table 3, p. 5, row 21 report
-44 kJ/mol-atom	CoZr2	298.15	model	Co–Zr	[3] Bratberg 2006	Table 6, p. 5, row 9 report
-44 kJ/mol-atom	CoZr2	298.15	model	Co–Zr	[3] Bratberg 2006 cites Miedema 1998	Table 6, p. 5, row 8 report
-32.547 per mol-atom	CoZr2	1290	model	Co–Zr	[2] Zhou 2021	Table 3, p. 5, row 23 report
-31.166 kJ/mol-atom	CoZr2	1290	model	Co–Zr	[1] Durga 2010	Table 5, p. 5, row 34 report
-30.745 per mol-atom	CoZr2	298.15	model	Co–Zr	[2] Zhou 2021 cites Agraval 2020 doi	Table 3, p. 5, row 22 report
-28.946 per mol-atom	CoZr2	298.15	model	Co–Zr	[2] Zhou 2021	Table 3, p. 5, row 24 report
-27.564 kJ/mol-atom	CoZr2	298.15	model	Co–Zr	[1] Durga 2010	Table 5, p. 5, row 59 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 CoZr2
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-33	kJ/mol-atom	2	5.000e-4	3.5 (unknown, calibrated)	3.5
-33	per mol-atom	2000	5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	2000
-26.4	per mol-atom	1000	5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	1000
-26.4	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-26.3	per mol-atom		5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-44	kJ/mol-atom		0.5	3.9 (model_calculated, calibrated)	3.9
-44	kJ/mol-atom		0.5	3.9 (model_calculated, calibrated)	3.9
-32.547	per mol-atom		5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-31.166	kJ/mol-atom		5.000e-4	3.9 (model_calculated, calibrated)	3.9
-30.745	per mol-atom		5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-28.946	per mol-atom		5.000e-4	unit 'per mol-atom' not convertible to kJ/mol-atom	unit 'per mol-atom' not convertible to kJ/mol-atom
-27.564	kJ/mol-atom		5.000e-5	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 CoZr2
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaaaye	-24.825	-0.257295	I4/mcm	0	0	no
OQMD	oqmd-29534	-25.161	-0.260781	I4/mcm	0.375	0.0039	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

A. Durga, K.C. Hari Kumar, Thermodynamic optimization of the Co–Zr system, Calphad 34, 200-205 (2010). doi:10.1016/j.calphad.2010.02.006
Chenyang Zhou, Hang Wang, Thermodynamic Descriptions of the Co–Zr and Co–Fe–Zr Systems, J. Phase Equilib. Diffus. 42, 77-90 (2021). doi:10.1007/s11669-020-00859-5
Johan Bratberg, Bo Jansson, Thermodynamic evaluation of the C−Co−W−Hf−Zr system for cemented carbides applications, JPED 27, 213-219 (2006). doi:10.1361/154770306x109746

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}
}