Nb system

70 accepted literature values from 12 paper(s) (experimental 7, model 9, DFT 47, unspecified 7); 0 calculated phase diagram(s). 5 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

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

Accepted values by evidence class
Evidence class	Values
experimental	7
model	9
DFT	47
unspecified	7

Accepted values by property group
Property group	Values
phase transition	2
formation	20
activity / EMF / Gibbs energy	2
crystal structure	46

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, Nb system (20)
Phase	Value	Class	Source	Location
(Co,Ni)Nb	16.9621 kJ/mol-atom	DFT	[1] Zhou 2020	Table V, p. 12, row 19 report
C14	15.37 kJ/mol (basis unstated)	DFT	[2] Pavlů 2009	Table 3, p. 3, row 3 report
C14	15.4 kJ/mol (basis unstated)	DFT	[2] Pavlů 2009 cites Sluiter 2006 doi	Table 3, p. 3, row 4 report
C15	16.2 kJ/mol (basis unstated)	DFT	[2] Pavlů 2009	Table 3, p. 3, row 9 report
C15	16.2 kJ/mol (basis unstated)	DFT	[2] Pavlů 2009 cites Sluiter 2006 doi	Table 3, p. 3, row 10 report
C15	16.33 kJ/mol (basis unstated)	DFT	[3] Lu 2017	Table 2, p. 3, row 11 report
C36	15.97 kJ/mol (basis unstated)	DFT	[2] Pavlů 2009	Table 3, p. 3, row 14 report
C36	16.11 kJ/mol (basis unstated)	DFT	[3] Lu 2017	Table 2, p. 3, row 36 report
D0_22	0.279 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 14 report
D0_22	20 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 14 report
D0_a	20 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 5 report
D0_a	74.948 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 5 report
D8_5	65 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 1 report
D8_5	209.344 kJ/mol (basis unstated)	unspecified	[4] Mathon 2009	Table 2, p. 10, row 1 report
Nb2:Nb	15.33 kJ/mol-atom	DFT	[5] Schmetterer 2014	Table 6, p. 7, row 16 report
Nb2:Nb	16.2 kJ/mol-atom	DFT	[5] Schmetterer 2014 cites Pavlu 2009 doi	Table 6, p. 7, row 17 report
Nb2:Nb	16.2 kJ/mol-atom	DFT	[5] Schmetterer 2014 cites Sluiter 2006 doi	Table 6, p. 7, row 18 report
τ1	25.46 kJ/mol (basis unstated)	DFT	[3] Lu 2017	Table 2, p. 3, row 56 report
τ2	15.51 kJ/mol (basis unstated)	DFT	[3] Lu 2017	Table 2, p. 3, row 23 report
τ2	16.54 kJ/mol (basis unstated)	DFT	[3] Lu 2017 cites Liu 2012 doi	Table 2, p. 3, row 24 report

Other properties

Phase transition (2)

Phase transition, Nb system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	1973 K	1973	other: Nb-solidus alloy: Nb 1	experimental	[6] Neto 1993 cites ref. 69Rud	Table 1, p. 3, row 8 report
Phase transition	2168 K	2168	other: Nb-solidus alloy: Nb 1	experimental	[6] Neto 1993 cites ref. 56Ely	Table 1, p. 3, row 43 report

Activity / EMF / Gibbs energy (2)

Activity / EMF / Gibbs energy, Nb system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Gibbs energy printed: Gm(ω)-Gm(β)	6878 J/mol	0	UNKNOWN alloy: Nb 1	model	[7] Yan 2016	Table 4, p. 5, row 4 report
Gibbs energy printed: Gm(ω)-Gm(β)	19267 J/mol	0	UNKNOWN alloy: Nb 1	DFT	[7] Yan 2016	Table 4, p. 5, row 3 report

Crystal structure (46)

Crystal structure, Nb system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	3.322 Å		(Nb) alloy: Nb 1	model	[8] Liu 2012 cites Wang 2004 doi	Table 5, p. 9, row 8 report
Lattice a	3.32 Å		(Nb) alloy: Nb 1	model	[8] Liu 2012	Table 5, p. 9, row 7 report
Lattice a	3.2929 Å	0	BCC alloy: Nb 1	DFT	[9] Ghosh 2002	Table 1, p. 6, row 7 report
Lattice a	5.467 Å	0	C14 alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 10 report
Lattice a	5.5 Å	0	C14 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 2 report
Lattice a	7.69 Å	0	C15 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 11 report
Lattice a printed: a	7.67 Å	0	C15 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 11 report
Lattice a	5.48 Å	0	C36 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 20 report
Lattice a printed: a	5.46 Å	0	C36 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 36 report
Lattice a	4.1999 Å	0	FCC alloy: Nb 1	DFT	[9] Ghosh 2002	Table 1, p. 6, row 9 report
Lattice a	2.8453 Å	0	HCP alloy: Nb 1	DFT	[9] Ghosh 2002	Table 1, p. 6, row 10 report
Lattice a	3.317 Å	0	Nb (bcc)	DFT	[10] Liu 2013	Table 1, p. 4, row 4 report
Lattice a	3.3 Å		Nb (bcc)	experimental	[10] Liu 2013 cites Kittel 1995	Table 1, p. 4, row 6 report
Lattice a	3.322 Å	0	Nb (bcc)	DFT	[10] Liu 2013 cites Wang 2004 doi	Table 1, p. 4, row 5 report
Lattice a	3.32 Å		Nonmagnetic BCC Nb alloy: Nb 1	unspecified	[2] Pavlů 2009	Table 1, p. 3, row 3 report
Lattice a printed: a	7.69 Å	0	UNKNOWN alloy: Nb 1	DFT	[5] Schmetterer 2014 cites Pavlu 2009 doi	Table 6, p. 7, row 17 report
Lattice a printed: a	7.74 Å	0	UNKNOWN alloy: Nb 1	DFT	[5] Schmetterer 2014	Table 6, p. 7, row 16 report
Lattice a	5.456 Å	0	μ alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 34 report
Lattice a printed: a	12.21 Å	0	τ1 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 56 report
Lattice a printed: a	5.48 Å	0	τ2 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 23 report
Lattice a printed: a	5.47 Å	0	τ2 alloy: Nb 1	model	[3] Lu 2017 cites Liu 2012 doi	Table 2, p. 3, row 24 report
Lattice a	3.3024 Å	4.2	BCC alloy: Nb 1	experimental	[9] Ghosh 2002	Table 1, p. 6, row 12 report
Lattice a	3.3024 Å	4.2	BCC alloy: Nb 1	experimental	[9] Ghosh 2002 cites ref. 1964Val	Table 1, p. 6, row 8 report
Lattice a	3.3024 Å	298.15	BCC alloy: Nb 1	experimental	[9] Ghosh 2002 cites ref. 1964Val	Table 1, p. 6, row 13 report
Lattice a	3.3 Å	298.15	Nb	model	[11] Li 2013 cites Daams 1991	Table 1, p. 2, row 1 report
Lattice a	3.3067 Å	298.15	Nb alloy: Nb 1	model	[12] Shao 2004 cites Villars 1991	Table 1, p. 2, row 2 report
Lattice a	3.3 Å	298.15	Nonmagnetic BCC Nb alloy: Nb 1	experimental	[2] Pavlů 2009 cites Villars 1991	Table 1, p. 3, row 4 report
Lattice c	8.869 Å	0	C14 alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 10 report
Lattice c	8.68 Å	0	C14 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 2 report
Lattice c	17.52 Å	0	C36 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 20 report
Lattice c printed: c	17.47 Å	0	C36 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 36 report
Lattice c	5.2551 Å	0	HCP alloy: Nb 1	DFT	[9] Ghosh 2002	Table 1, p. 6, row 10 report
Lattice c	28.825 Å	0	μ alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 34 report
Lattice c printed: c	8.66 Å	0	τ2 alloy: Nb 1	DFT	[3] Lu 2017	Table 2, p. 3, row 23 report
Lattice c printed: c	8.87 Å	0	τ2 alloy: Nb 1	model	[3] Lu 2017 cites Liu 2012 doi	Table 2, p. 3, row 24 report
Molar volume printed: V0	18.34 Å3/atom	0	(Co,Ni)Nb alloy: Nb 1	DFT	[1] Zhou 2020	Table V, p. 12, row 19 report
Molar volume printed: V0	18.12 Å3/atom	0	bcc(Nb) alloy: Nb 1	DFT	[1] Zhou 2020	Table V, p. 12, row 2 report
lattice 2v atom	3.796 10^7 pm^3	0	C36 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 20 report
lattice v atom	1.894 10^7 pm^3	0	C14 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 2 report
lattice v atom	1.898 10^7 pm^3	0	C15 alloy: Nb 1	DFT	[2] Pavlů 2009	Table 2, p. 3, row 11 report
lattice v0	36.7 Å3		(Nb) alloy: Nb 1	model	[8] Liu 2012 cites Wang 2004 doi	Table 5, p. 9, row 8 report
lattice v0	36.6 Å3		(Nb) alloy: Nb 1	model	[8] Liu 2012	Table 5, p. 9, row 7 report
lattice v0	229.6 Å3	0	C14 alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 10 report
lattice v0	229.6 Å3 per formula unit	0	C14 alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 10 report
lattice v0	743 Å3 per formula unit	0	μ alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 34 report
lattice v0	743 Å3	0	μ alloy: Nb 1	DFT	[8] Liu 2012	Table 4, p. 8, row 34 report

Sources

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

Chenyang Zhou, Cuiping Guo, Jingbo Li, Changrong Li, Zhenmin Du, Key Experiments and Thermodynamic Description of the Co-Nb-Ni System, Metall Mater Trans A 51, 5892-5911 (2020). doi:10.1007/s11661-020-05963-2
J. Pavlů, J. Vřešt’ál, M. Šob, Re-modeling of Laves phases in the Cr–Nb and Cr–Ta systems using first-principles results, Calphad 33, 179-186 (2009). doi:10.1016/j.calphad.2008.04.006
Hai-Jin Lu, Nan Zou, Xu-Shan Zhao, Jian-Yun Shen, Xiao-Gang Lu, Yan-Lin He, Thermodynamic investigation of the Zr-Fe-Nb system and its applications, Intermetallics 88, 91-100 (2017). doi:10.1016/j.intermet.2017.05.008
Muriel Mathon, Damien Connétable, Bo Sundman, Jacques Lacaze, Calphad-type assessment of the Fe–Nb–Ni ternary system, Calphad 33, 136-161 (2009). doi:10.1016/j.calphad.2008.10.005
Clemens Schmetterer, Alexandra Khvan, Aurélie Jacob, Bengt Hallstedt, Torsten Markus, A New Theoretical Study of the Cr-Nb System, J. Phase Equilib. Diffus. 35, 434-444 (2014). doi:10.1007/s11669-014-0313-y
Joaquim G. Costa Neto, Suzana G. Fries, Hans Leo Lukas, Sérgio Gama, Günter Effenberg, Thermodynamic optimisation of the Nb-Cr system, Calphad 17, 219-228 (1993). doi:10.1016/0364-5916(93)90001-r
Jia-Yi Yan, G.B. Olson, Computational thermodynamics and kinetics of displacive transformations in titanium-based alloys, Journal of Alloys and Compounds 673, 441-454 (2016). doi:10.1016/j.jallcom.2016.02.251
Shuhong Liu, Bengt Hallstedt, Denis Music, Yong Du, Ab initio calculations and thermodynamic modeling for the Fe–Mn–Nb system, Calphad 38, 43-58 (2012). doi:10.1016/j.calphad.2012.03.004
G. Ghosh, A. van de Walle, M. Asta, G.B. Olson, Phase stability of the Hf-Nb system: From first-principles to CALPHAD, Calphad 26, 491-511 (2002). doi:10.1016/s0364-5916(02)80003-7
Xuan L. Liu, Chelsey Z. Hargather, Zi-Kui Liu, First-principles aided thermodynamic modeling of the Nb–Re system, Calphad 41, 119-127 (2013). doi:10.1016/j.calphad.2013.02.006
Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013). doi:10.1016/j.calphad.2013.04.004
G. Shao, Thermodynamic assessment of the Nb–Si–Al system, Intermetallics 12, 655-664 (2004). doi:10.1016/j.intermet.2004.03.011

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 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_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}
}