# Nb–O–Ta–V system > Nb–O–Ta–V system: 6 accepted literature values (mixing / partial 3, heat capacity / entropy / enthalpy 3) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote. HTML: https://data.orchid-project.org/systems/NB-O-TA-V.html · Markdown: https://data.orchid-project.org/systems/NB-O-TA-V.md 6 accepted literature values from 1 paper(s) (unspecified 6); 0 calculated phase diagram(s). Data: [JSON](https://data.orchid-project.org/literature/systems/NB-O-TA-V.json) · [CSV](https://data.orchid-project.org/systems/NB-O-TA-V.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#NB-O-TA-V) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/NB-O-TA-V.html) · [Markdown](https://data.orchid-project.org/systems/NB-O-TA-V.md) Table: Accepted values by evidence class | Evidence class | Values | |---|---:| | unspecified | 6 | Table: Accepted values by property group | Property group | Values | |---|---:| | mixing / partial | 3 | | heat capacity / entropy / enthalpy | 3 | ## Other properties ### Mixing / partial (3) Table: Mixing / partial, Nb–O–Ta–V system | Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote | |---|---:|---:|---|---|---|---|---| | Partial enthalpy; _printed: ΔH° \[½O2(g) → MOx\]_ | -439 kJ/mol (basis unstated) | 1500 | UNKNOWN | unspecified | [1] Meisner 2022 | Table 3, p. 30, row 3; `ORC-KYUL565HQF.bebbd2` | | | Partial enthalpy; _printed: ΔH° \[½O2(g) → MOx\]_ | -714 kJ/mol (basis unstated) | 1500 | UNKNOWN | unspecified | [1] Meisner 2022; _cites ref. 62_ | Table 3, p. 30, row 1; `ORC-L2SQJEPOMV.ce17f0` | | | Partial enthalpy; _printed: ΔH° \[½O2(g) → MOx\]_ | -316 kJ/mol (basis unstated) | 1500 | UNKNOWN | unspecified | [1] Meisner 2022; _cites ref. 63_ | Table 3, p. 30, row 2; `ORC-OJ7QXVJ7HJ.01b4c0` | | ### Heat capacity / entropy / enthalpy (3) Table: Heat capacity / entropy / enthalpy, Nb–O–Ta–V system | Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote | |---|---:|---:|---|---|---|---|---| | Entropy; _printed: ΔS° \[½O2(g) → MOx\]_ | -73.5 J/mol | 1500 | UNKNOWN | unspecified | [1] Meisner 2022 | Table 3, p. 30, row 3; `ORC-KYUL565HQF.6f1d22` | | | Entropy; _printed: ΔS° \[½O2(g) → MOx\]_ | -75.2 J/mol | 1500 | UNKNOWN | unspecified | [1] Meisner 2022; _cites ref. 62_ | Table 3, p. 30, row 1; `ORC-L2SQJEPOMV.e4a43a` | | | Entropy; _printed: ΔS° \[½O2(g) → MOx\]_ | -76.4 J/mol | 1500 | UNKNOWN | unspecified | [1] Meisner 2022; _cites ref. 63_ | Table 3, p. 30, row 2; `ORC-OJ7QXVJ7HJ.aab692` | | ## Sources Reporting papers the values were read from (a value cited from another work names that work in its row). 1. 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](https://doi.org/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). https://doi.org/10.5281/zenodo.23735569 - R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/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. ```bibtex @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_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} } ``` --- Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).