Nb–O system

1 accepted literature values from 1 paper(s) (experimental 1); 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 (10) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	1

Accepted values by property group
Property group	Values
phase transition	1

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
NbO-07Jer.tdb	R. Jerlerud Perez, A.R. Massih, J. Nucl. Mater., 360, 242-54(2007). doi:10.1016/j.jnucmat.2006.10.008	`30d68ef18e1752dc4e245c00c4c55e1b7259640026ca3cc52bc24267ef0f725a`	viewer · TDB · JSON
NbO-97Dup-LB.tdb	N. Dupin, I. Ansara, unpublished, 1997.	`7461691cb95cdbdf478fa72adf405f77eab04a5b884cf22d8abdf81fffd0e723`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
NbO-07Jer.tdb	2191.87	BCC_A2 (x(O) 0.09041) + ION (x(O) 0.39373) + NBO (x(O) 0.5)
NbO-07Jer.tdb	2099.18	NBO (x(O) 0.5) + ION (x(O) 0.61587) + NBO2 (x(O) 0.66667)
NbO-07Jer.tdb	1966.19	ION (x(O) 0.71423) + NB2O5 (x(O) 0.71429) + GAS (x(O) 1)
NbO-07Jer.tdb	1782.33	NBO2 (x(O) 0.66667) + ION (x(O) 0.70907) + NB2O5 (x(O) 0.71429)
NbO-97Dup-LB.tdb	2194.85	BCC_A2 (x(O) 0.06331) + ION (x(O) 0.40427) + NBO (x(O) 0.5)
NbO-97Dup-LB.tdb	2099.18	NBO (x(O) 0.5) + ION (x(O) 0.61587) + NBO2 (x(O) 0.66667)
NbO-97Dup-LB.tdb	1966.19	ION (x(O) 0.71423) + NB2O5 (x(O) 0.71429) + GAS (x(O) 1)
NbO-97Dup-LB.tdb	1782.33	NBO2 (x(O) 0.66667) + ION (x(O) 0.70907) + NB2O5 (x(O) 0.71429)

Convex hulls: Materials Project DFT hull · OQMD DFT hull

Other properties

Phase transition (1)

Phase transition, Nb–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	1070 K	1070	NbO2	experimental	[1] Pérez 2007 cites Pynn 1976 doi	p. 4 report	NbO2 undergoes a phase transition at about 1070 K from a high temperature tetragonal phase to a low temperature distorted tetragonal structure [31].

Sources

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

R. Jerlerud Pérez, A.R. Massih, Thermodynamic evaluation of the Nb–O–Zr system, Journal of Nuclear Materials 360, 242-254 (2007). doi:10.1016/j.jnucmat.2006.10.008

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}
}