O–Ta system

41 accepted literature values from 2 paper(s) (experimental 23, model 6, DFT 12); 0 calculated phase diagram(s). 10 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

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

Accepted values by evidence class
Evidence class	Values
experimental	23
model	6
DFT	12

Accepted values by property group
Property group	Values
invariant reaction	8
phase transition	3
crystal structure	30

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull TaO-22Mei-ass · CALPHAD hull TaO-22Mei-ion

Invariant reactions (literature)

Invariant reactions reported in the literature for the O–Ta system (8)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
2193.15	monotectic: liquid1 <-> bcc + liquid2	liquid1: Ta 0.724; bcc: Ta 0.949; liquid2: Ta 0.419	model	[1] Gebauer 2022 cites Meisner 2022 doi	Table 2, p. 6, row 4 report
2153.15	monotectic: liquid1 <-> bcc + liquid2	liquid1: Ta 0.658; bcc: Ta 0.951; liquid2: Ta 0.351	model	[1] Gebauer 2022	Table 2, p. 6, row 1 report
2153.15	monotectic: liquid1 <-> bcc + liquid2	liquid1: Ta 0.57; bcc: Ta 0.943; liquid2: Ta 0.35	experimental	[1] Gebauer 2022 cites Garg 1996 doi	Table 2, p. 6, row 2 report
2011.15	monotectic: liquid1 <-> bcc + liquid2	liquid1: Ta 0.707; bcc: Ta 0.949; liquid2: Ta 0.414	model	[1] Gebauer 2022 cites Meisner 2022 doi	Table 2, p. 6, row 3 report
1914.15	eutectic: liquid2 <-> bcc + αTa2O5	liquid2: Ta 0.397; bcc: Ta 0.945; αTa2O5: Ta 0.286	model	[1] Gebauer 2022 cites Meisner 2022 doi	Table 2, p. 6, row 8 report
1823.15	eutectic: liquid2 <-> bcc + αTa2O5	liquid2: Ta 0.29; bcc: Ta 0.95; αTa2O5: Ta 0.286	experimental	[1] Gebauer 2022 cites Garg 1996 doi	Table 2, p. 6, row 6 report
1823.15	eutectic: liquid2 <-> bcc + αTa2O5	liquid2: Ta 0.32; bcc: Ta 0.95; αTa2O5: Ta 0.286	model	[1] Gebauer 2022	Table 2, p. 6, row 5 report
1787.15	eutectic: liquid2 <-> bcc + αTa2O5	liquid2: Ta 0.387; bcc: Ta 0.952; αTa2O5: Ta 0.286	model	[1] Gebauer 2022 cites Meisner 2022 doi	Table 2, p. 6, row 7 report

Other properties

Phase transition (3)

Phase transition, O–Ta system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	2058 K	2058	liquid	experimental	[2] Meisner 2022 cites ref. 18	p. 4 report	The melting temperatures of the α and β phases are 2145 K and 2058 K, respectively [18].
Phase transition	2145 K	2145	α-Ta2O5 + liquid	experimental	[2] Meisner 2022 cites ref. 18	p. 4 report	The melting temperatures of the α and β phases are 2145 K and 2058 K, respectively [18].
Phase transition	3290 K	3290	liquid	experimental	[2] Meisner 2022 cites ref. 45	p. 8 report	The liquid is the least understood aspect of the Ta-O system as quantitative measurements are difficult to obtain at ultra-high temperatures (Tm,Ta2O5 = 2145 K [18] and Tm,Ta = 3290 K [45], where Tm is the melting temperature).

Crystal structure (30)

Crystal structure, O–Ta system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	6.2 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 16	Table 1, p. 27, row 4 report
Lattice a	6.22 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 21	Table 1, p. 27, row 2 report
Lattice a	3.81 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 27	Table 1, p. 27, row 10 report
Lattice a	7.13 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 25	Table 1, p. 27, row 8 report
Lattice a	6.25 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 26	Table 1, p. 27, row 9 report
Lattice a	3.87 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 24	Table 1, p. 27, row 7 report
Lattice a	14.65 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 22	Table 1, p. 27, row 3 report
Lattice a	6.2 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 23	Table 1, p. 27, row 5 report
Lattice a	6.19 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites Cardonne	Table 1, p. 27, row 6 report
Lattice a	44 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 20	Table 1, p. 27, row 1 report
Lattice b	3.66 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 16	Table 1, p. 27, row 4 report
Lattice b	3.68 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 21	Table 1, p. 27, row 2 report
Lattice b	12.79 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 27	Table 1, p. 27, row 10 report
Lattice b	6.03 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 25	Table 1, p. 27, row 8 report
Lattice b	7.4 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 26	Table 1, p. 27, row 9 report
Lattice b	3.9 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 24	Table 1, p. 27, row 7 report
Lattice b	9.4 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 22	Table 1, p. 27, row 3 report
Lattice b	40.29 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 23	Table 1, p. 27, row 5 report
Lattice b	69.55 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites Cardonne	Table 1, p. 27, row 6 report
Lattice b	3.89 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 20	Table 1, p. 27, row 1 report
Lattice c	3.89 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 16	Table 1, p. 27, row 4 report
Lattice c	7.79 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 21	Table 1, p. 27, row 2 report
Lattice c	3.79 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 27	Table 1, p. 27, row 10 report
Lattice c	3.82 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 25	Table 1, p. 27, row 8 report
Lattice c	3.83 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 26	Table 1, p. 27, row 9 report
Lattice c	13.13 not_printed		β-Ta2O5	DFT	[2] Meisner 2022 cites ref. 24	Table 1, p. 27, row 7 report
Lattice c	31.19 not_printed		β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 22	Table 1, p. 27, row 3 report
Lattice c	3.89 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 23	Table 1, p. 27, row 5 report
Lattice c	3.89 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites Cardonne	Table 1, p. 27, row 6 report
Lattice c	6.21 not_printed	298.15	β-Ta2O5	experimental	[2] Meisner 2022 cites ref. 20	Table 1, p. 27, row 1 report

Sources

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

Julian Gebauer, Peter Franke, Hans Jürgen Seifert, Thermodynamic Evaluation of the system Ta–O and Preliminary Assessment of the Systems Al–Nb–O and Al–Ta–O, Adv Eng Mater 24 (2022). doi:10.1002/adem.202200162
Kevin J. Meisner, Rahim Zaman, Bi-Cheng Zhou, Thermodynamic modeling of the Ta-O system, Calphad 76, 102391 (2022). doi:10.1016/j.calphad.2022.102391

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-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); 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); 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_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}
}