Gd–O system

43 accepted literature values from 2 paper(s) (experimental 19, model 21, DFT 3); 2 calculated phase diagram(s). 1 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 (11) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	19
model	21
DFT	3

Accepted values by property group
Property group	Values
phase transition	18
formation	2
heat capacity / entropy / enthalpy	11
crystal structure	7
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
GdO-14McM.tdb	J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, J. Nucl. Mater., 452, 397-406(2014). doi:10.1016/j.jnucmat.2014.04.047	`b72717c7ab25c852bf747a3bcf950bf18ed32b6675524a2ab2f10c4f06c13684`	viewer · TDB · JSON
GdO-23Nak.tdb	R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023). doi:10.1016/j.calphad.2023.102636	`bd0ea93f229ea2a27c585edd666b6b889b92c86a63daaa54de3332fbbd322ced`	viewer · TDB · JSON

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull GdO-14McM

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, Gd–O system (2)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location	Quote
B-Gd2O3	Gd2O3	-363.94 kJ/mol-atom	298.15	model	-375.849 (mp-aaabcsws)	-365.932 (oqmd-7281)	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 11 report
C-Gd₂O₃	Gd2O3	-365.506 kJ/mol-atom	298.15	model	-375.849 (mp-aaabcsws)	-365.932 (oqmd-7281)	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 10 report

Other properties

Phase transition (18)

Phase transition, Gd–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Phase transition	1425 K	1425	polymorphic: C <=> B alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 3 report
Phase transition	2353 K	2353	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Coutures 1976	Table 2.1, p. 6, row 65 report
Phase transition	2443 K	2443	polymorphic: B <=> A alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 9 report
Phase transition	2443 K	2443	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Rykova 1976	Table 2.1, p. 6, row 73 report
Phase transition	2443 K	2443	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 62 report
Phase transition	2443 K	2443	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Tresvyatkii 1971	Table 2.1, p. 6, row 67 report
Phase transition	2443 K	2443	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 2.1, p. 6, row 74 report
Phase transition	2443 K	2443	polymorphic: B ⟺ A alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Shevtchenko 1985	Table 2.1, p. 6, row 70 report
Phase transition	2473 K	2473	polymorphic: A ⟺ H alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 63 report
Phase transition	2473 K	2473	polymorphic: A ⟺ H alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Tresvyatkii 1971	Table 2.1, p. 6, row 68 report
Phase transition	2473 K	2473	polymorphic: A ⟺ H alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Shevtchenko 1985	Table 2.1, p. 6, row 71 report
Phase transition	2481 K	2481	polymorphic: A <=> H alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 16 report
Phase transition	2481 K	2481	polymorphic: A ⟺ H alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 2.1, p. 6, row 75 report
Phase transition	2633 K	2633	polymorphic: H <=> X alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 2.2, p. 8, row 30 report
Phase transition	2633 K	2633	polymorphic: H ⟺ X alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Coutures 1976	Table 2.1, p. 6, row 66 report
Phase transition	2633 K	2633	polymorphic: H ⟺ X alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Tresvyatkii 1971	Table 2.1, p. 6, row 69 report
Phase transition	2633 K	2633	polymorphic: H ⟺ X alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Foex 1966	Table 2.1, p. 6, row 64 report
Phase transition	2643 K	2643	polymorphic: H ⟺ X alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Shevtchenko 1985	Table 2.1, p. 6, row 72 report

Heat capacity / entropy / enthalpy (11)

Heat capacity / entropy / enthalpy, Gd–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: °S	157.37 unknown	298.15	B-Gd₂O₃ alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 11 report
Entropy printed: °S	150.61 unknown	298.15	C-Gd2O3 alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 10 report
Entropy printed: Δtrs°S	3.737 unknown	1425	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 12 report
Entropy printed: Δtrs°S	2.579 unknown	2443	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 13 report
Entropy printed: ΔS	2.579 J mol−1 K−1	2443	Gd2O3 alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 5.1, p. 18, row 13 report
Entropy printed: ΔS	2.579 J mol^-1 K^-1	2443	UNKNOWN alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 5.1, p. 18, row 13 report
Entropy printed: Δtrs°S	13.986 unknown	2481	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 14 report
Entropy printed: ΔS	13.986 J mol−1 K−1	2481	Gd2O3 alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 5.1, p. 18, row 14 report
Entropy printed: ΔS	13.986 J mol^-1 K^-1	2481	UNKNOWN alloy: Gd 0.4, O 0.6	experimental	[1] ZINKEVICH 2007 cites Barkhatov 1981	Table 5.1, p. 18, row 14 report
Entropy printed: Δtrs°S	4.569 unknown	2633	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 15 report
Entropy printed: Δtrs°S	26.625 unknown	2693	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 16 report

Crystal structure (7)

Crystal structure, Gd–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	10.283 Å		Gd2O3 alloy: O 0.6	experimental	[2] McMurray 2014 cites Heiba 2002 doi	Table 1, p. 4, row 2 report
Lattice a	10.805 Å	0	Gd2O3 alloy: O 0.6	DFT	[2] McMurray 2014	Table 1, p. 4, row 1 report
Lattice a	5.496 Å	0	GdO2 alloy: O 0.666667	DFT	[2] McMurray 2014	Table 1, p. 4, row 3 report
Lattice a	5.497 Å	0	GdO2 alloy: O 0.666667	DFT	[2] McMurray 2014	Table 1, p. 4, row 4 report
lattice molar volume	43.265 cm3 mol-1	298.15	Gd2O3 (A-type) alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 10 report
lattice molar volume	43.403 cm3 mol-1	298.15	Gd2O3 (B-type) alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 10 report
lattice molar volume	47.574 cm3 mol-1	298.15	Gd2O3 (C-type) alloy: Gd 0.4, O 0.6	model	[1] ZINKEVICH 2007	Table 3.1, p. 12, row 10 report

Other property (5)

Other property, Gd–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Transition enthalpy printed: Δtrs°H	5325 unknown	1425	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 12 report
Transition enthalpy printed: Δtrs°H	6300 unknown	2443	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 13 report
Transition enthalpy printed: Δtrs°H	34700 unknown	2481	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 14 report
Transition enthalpy printed: Δtrs°H	12031 unknown	2633	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 15 report
Transition enthalpy printed: Δtrs°H	71702 unknown	2693	B-Gd₂O₃	model	[1] ZINKEVICH 2007	Table 6.1, p. 25, row 16 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
J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014). doi:10.1016/j.jnucmat.2014.04.047

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}
}