Eu–O system

31 accepted literature values from 1 paper(s) (experimental 6, model 21, unspecified 4); 1 calculated phase diagram(s).

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (8) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	6
model	21
unspecified	4

Accepted values by property group
Property group	Values
phase transition	12
formation	2
heat capacity / entropy / enthalpy	9
crystal structure	3
other property	5

Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
EuO-07Zin.tdb	M. Zinkevich, Prog. Mater. Sci., 52, 597-647(2007). doi:10.1016/j.pmatsci.2006.09.002	`98ca41c17d4bfe5ac494d3e2ec47ec95388bac43545fda0770d0b3b856a10649`	viewer · TDB · JSON

Convex hulls: Materials Project DFT hull · OQMD DFT hull

Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from dft_parity.json.

Enthalpies of formation, Eu–O system (2)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location	Quote
B-Eu2O3	Eu2O3	-330.08 kJ/mol-atom	298.15	model	-307.248 (mp-aaacphfp)	-276.415 (oqmd-1820519)	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 4 report
C-Eu2O3	Eu2O3	-331.316 kJ/mol-atom	298.15	model	-307.248 (mp-aaacphfp)	-276.415 (oqmd-1820519)	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 3 report

Other properties

Phase transition (12)

Phase transition, Eu–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Phase transition	298.15 K	298.15	polymorphic: B ⇒ A alloy: Eu 0.4, O 0.6	unspecified	[1] ZINKEVICH 2007 cites Chen 1994	Table 2.3, p. 10, row 11 report
Phase transition	298.15 K	298.15	polymorphic: C ⇒ B alloy: Eu 0.4, O 0.6	unspecified	[1] ZINKEVICH 2007 cites Chen 1992	Table 2.3, p. 10, row 10 report
Phase transition	894 K	894	polymorphic: C <=> B alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 2 report
Phase transition	2323 K	2323	polymorphic: B <=> A alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 8 report
Phase transition	2323 K	2323	polymorphic: B ⟺ A alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 56 report
Phase transition	2323 K	2323	polymorphic: B ⟺ A alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Andrievskaya 1997	Table 2.1, p. 6, row 59 report
Phase transition	2413 K	2413	polymorphic: A <=> H alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 15 report
Phase transition	2413 K	2413	polymorphic: A ⟺ H alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Andrievskaya 1997	Table 2.1, p. 6, row 60 report
Phase transition	2413 K	2413	polymorphic: A ⟺ H alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 57 report
Phase transition	2543 K	2543	polymorphic: H <=> X alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 29 report
Phase transition	2543 K	2543	polymorphic: H ⟺ X alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Andrievskaya 1997	Table 2.1, p. 6, row 61 report
Phase transition	2543 K	2543	polymorphic: H ⟺ X alloy: Eu 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 58 report

Heat capacity / entropy / enthalpy (9)

Heat capacity / entropy / enthalpy, Eu–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: ΔS	1.504 J mol−1 K−1		Eu2O3 alloy: Eu 0.4, O 0.6	unspecified	[1] ZINKEVICH 2007 cites Chen 1994	Table 5.1, p. 18, row 11 report
Entropy printed: ΔS	1.504 J mol^-1 K^-1		UNKNOWN alloy: Eu 0.4, O 0.6	unspecified	[1] ZINKEVICH 2007 cites Chen 1994	Table 5.1, p. 18, row 11 report
Entropy printed: °S	142.74 unknown	298.15	B-Eu₂O₃ alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 4 report
Entropy printed: °S	134.61 unknown	298.15	C-Eu2O3 alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 3 report
Entropy printed: Δtrs°S	4.914 unknown	894.5	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 5 report
Entropy printed: Δtrs°S	1.504 unknown	2323	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 6 report
Entropy printed: Δtrs°S	13.986 unknown	2413	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 7 report
Entropy printed: Δtrs°S	4.569 unknown	2543	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 8 report
Entropy printed: Δtrs°S	41.663 unknown	2623	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 9 report

Crystal structure (3)

Crystal structure, Eu–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
lattice molar volume	43.538 cm3 mol-1	298.15	Eu2O3 (A-type) alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 9 report
lattice molar volume	44.246 cm3 mol-1	298.15	Eu2O3 (B-type) alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 9 report
lattice molar volume	48.328 cm3 mol-1	298.15	Eu2O3 (C-type) alloy: Eu 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 9 report

Other property (5)

Other property, Eu–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Transition enthalpy printed: Δtrs°H	4395 unknown	894.5	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 5 report
Transition enthalpy printed: Δtrs°H	3494 unknown	2323	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 6 report
Transition enthalpy printed: Δtrs°H	33748 unknown	2413	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 7 report
Transition enthalpy printed: Δtrs°H	11619 unknown	2543	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 8 report
Transition enthalpy printed: Δtrs°H	109282 unknown	2623	B-Eu₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 9 report

Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007). doi:10.1016/j.pmatsci.2006.09.002

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-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735859
R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735891
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); 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; 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). 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_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@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}
}