La–O system

47 accepted literature values from 2 paper(s) (experimental 31, model 14, unspecified 2); 2 calculated phase diagram(s). 6 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (15) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	31
model	14
unspecified	2

Accepted values by property group
Property group	Values
phase transition	19
formation	17
heat capacity / entropy / enthalpy	8
crystal structure	3

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
LaO-01Gru.tdb	A.N. Grundy, B. Hallstedt, L.J. Gauckler, J. Phase Equilib., 22, 105-13(2001). doi:10.1361/105497101770338950	`dd70787d0d64865c3636a46845bb2dbeccb575b1c515332d2b933a3966b68600`	viewer · TDB · JSON
LaO-07Zin.tdb	M. Zinkevich, Prog. Mater. Sci., 52, 597-647(2007). doi:10.1016/j.pmatsci.2006.09.002	`c8176e51a3d7e85115b4fd78fdd64e381a6d1011fab606a5a355fc028a9bf5f9`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
LaO-01Gru.tdb	2382.84	ION (x(O) 0.516) + X_LA2O3 (x(O) 0.58852) + H_LA2O3 (x(O) 0.58852)
LaO-01Gru.tdb	2382.84	H_LA2O3 (x(O) 0.59997) + X_LA2O3 (x(O) 0.59997) + GAS (x(O) 1)
LaO-01Gru.tdb	2312.72	ION (x(O) 0.49292) + H_LA2O3 (x(O) 0.58814) + A_LA2O3_D52 (x(O) 0.58814)
LaO-01Gru.tdb	2312.72	A_LA2O3_D52 (x(O) 0.59998) + H_LA2O3 (x(O) 0.59998) + GAS (x(O) 1)
LaO-01Gru.tdb	1169.18	BCC_A2 (x(O) 0.0673) + ION (x(O) 0.07877) + A_LA2O3_D52 (x(O) 0.59417)
LaO-01Gru.tdb	1137.66	BCC_A2 (x(O) 0.06302) + FCC_A1 (x(O) 0.06323) + A_LA2O3_D52 (x(O) 0.5945)
LaO-01Gru.tdb	552.91	FCC_A1 (x(O) 0.00403) + DHCP (x(O) 0.00443) + A_LA2O3_D52 (x(O) 0.59953)

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull LaO-01Gru · CALPHAD hull LaO-05Che

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, La–O system (17)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
A-La2O3	La2O3	-358.32 kJ/mol-atom	298.15	model	-373.797 (mp-aaaaadke)	-358.204 (oqmd-30652)	[1] ZINKEVICH 2007	Table 6.1, p. 24, row 13 report
La2O3		-2255.2 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Roth 1940	Table 3, p. 3, row 11 report
La2O3		-2255.2 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Roth 1940	Table 3, p. 3, row 3 report
La2O3		-1907.4 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Moose 1932	Table 3, p. 3, row 10 report
La2O3		-1907.4 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Moose 1932	Table 3, p. 3, row 2 report
La2O3		-1866.1 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Von 1959	Table 3, p. 3, row 5 report
La2O3		-1866.1 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Von 1959	Table 3, p. 3, row 13 report
La2O3		-1862.1 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Muthmann 1904 doi	Table 3, p. 3, row 1 report
La2O3		-1862.1 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Muthmann 1904 doi	Table 3, p. 3, row 9 report
La2O3		-1797.9 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Gvelesiani 1967	Table 3, p. 3, row 15 report
La2O3		-1797.9 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Gvelesiani 1967	Table 3, p. 3, row 7 report
La2O3		-1795.5 kJ/mol (basis unstated)	298.15	model			[2] Grundy 2001	Table 3, p. 3, row 8 report
La2O3		-1795.5 kJ/mol (basis unstated)	298.15	model			[2] Grundy 2001	Table 3, p. 3, row 16 report
La2O3		-1794.5 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Fitzgibbon 1965 doi	Table 3, p. 3, row 14 report
La2O3		-1794.5 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Fitzgibbon 1965 doi	Table 3, p. 3, row 6 report
La2O3		-1793.3 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Huber 1953 doi	Table 3, p. 3, row 12 report
La2O3		-1793.3 kJ/mol (basis unstated)	298.15	experimental			[2] Grundy 2001 cites Huber 1953 doi	Table 3, p. 3, row 4 report

Other properties

Phase transition (19)

Phase transition, La–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Phase transition	2113 K	2113	other: [1913Ruf]	experimental	[2] Grundy 2001 cites Ruff 1913 doi	Table 1, p. 2, row 1 report
Phase transition	2303 K	2303	polymorphic: A ⟺ H alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Shevtchenko 1985	Table 2.1, p. 6, row 17 report
Phase transition	2313 K	2313	polymorphic: A <=> H alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 10 report
Phase transition	2313 K	2313	polymorphic: A ⟺ H alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Coutures 1976	Table 2.1, p. 6, row 13 report
Phase transition	2313 K	2313	polymorphic: A ⟺ H alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Molodkin 1982	Table 2.1, p. 6, row 19 report
Phase transition	2313 K	2313	polymorphic: A ⟺ H alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 11 report
Phase transition	2323 K	2323	polymorphic: A ⟺ H alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Tresvyatkii 1971	Table 2.1, p. 6, row 15 report
Phase transition	2363 K	2363	polymorphic: H ⟺ X alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Molodkin 1982	Table 2.1, p. 6, row 20 report
Phase transition	2373 K	2373	polymorphic: H <=> X alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 24 report
Phase transition	2373 K	2373	polymorphic: H ⟺ X alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Coutures 1976	Table 2.1, p. 6, row 14 report
Phase transition	2373 K	2373	polymorphic: H ⟺ X alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Shevtchenko 1985	Table 2.1, p. 6, row 18 report
Phase transition	2383 K	2383	polymorphic: H ⟺ X alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 12 report
Phase transition	2413 K	2413	polymorphic: H ⟺ X alloy: La 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Tresvyatkii 1971	Table 2.1, p. 6, row 16 report
Phase transition	2490 K	2490	other: [1967Mor]	experimental	[2] Grundy 2001 cites Mordovin 1967	Table 1, p. 2, row 4 report
Phase transition	2529 K	2529	other: [1967Nog]	experimental	[2] Grundy 2001 cites Noguchi 1968	Table 1, p. 2, row 5 report
Phase transition	2577 K	2577	other: [1966Sat]	experimental	[2] Grundy 2001 cites Sata 1966	Table 1, p. 2, row 3 report
Phase transition	2586 K	2586	other: [1997SGT], this study	unspecified	[2] Grundy 2001	Table 1, p. 2, row 7 report
Phase transition	2588 K	2588	other: [1932War]	unspecified	[2] Grundy 2001 cites ref. 1932War	Table 1, p. 2, row 2 report
Phase transition	2593 K	2593	other: [1975Cou]	experimental	[2] Grundy 2001 cites Coutures 1975	Table 1, p. 2, row 6 report

Heat capacity / entropy / enthalpy (8)

Heat capacity / entropy / enthalpy, La–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: °S	127.38 unknown	298.15	A-La2O3 alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 6.1, p. 24, row 13 report
Entropy printed: -ΔS298.15	-292.88 J/mol·K	298.15	La2O3 alloy: O 0.6	experimental	[2] Grundy 2001 cites Justice 1963 doi	Table 4, p. 4, row 2 report
Entropy printed: S298.15	25.464 J/mol-atom/K	298.15	La2O3 alloy: O 0.6	model	[2] Grundy 2001 cites Justice 1963 doi	Table 2, p. 3, row 1 report
Entropy printed: S298.15	25.468 J/mol-atom/K	298.15	La2O3 alloy: O 0.6	model	[2] Grundy 2001	Table 2, p. 3, row 4 report
Entropy printed: S298.15	25.59 J/mol-atom/K	298.15	La2O3 alloy: O 0.6	model	[2] Grundy 2001 cites Goldstein 1959 doi	Table 2, p. 3, row 2 report
Entropy printed: -ΔS298.15	-294.02 J/mol·K	298.15	La2O3 alloy: O 0.6	model	[2] Grundy 2001	Table 4, p. 4, row 3 report
Entropy printed: S298.15	25.714 J/mol-atom/K	298.15	La2O3 alloy: O 0.6	model	[2] Grundy 2001 cites King 1961	Table 2, p. 3, row 3 report
Entropy printed: -ΔS298.15	-294.56 J/mol·K	298.15	La2O3 alloy: O 0.6	experimental	[2] Grundy 2001 cites King 1961	Table 4, p. 4, row 1 report

Crystal structure (3)

Crystal structure, La–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
lattice molar volume	49.627 cm3 mol-1	298.15	La2O3 (A-type) alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 3 report
lattice molar volume	50.748 cm3 mol-1	298.15	La2O3 (B-type) alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 3 report
lattice molar volume	55.442 cm3 mol-1	298.15	La2O3 (C-type) alloy: La 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 3 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
A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001). doi:10.1361/105497101770338950

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}
}