B–Nb system

68 accepted literature values from 3 paper(s) (experimental 21, model 22, DFT 6, unspecified 19); 0 calculated phase diagram(s). 2 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · phases (11) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	21
model	22
DFT	6
unspecified	19

Accepted values by property group
Property group	Values
invariant reaction	32
formation	8
heat capacity / entropy / enthalpy	9
crystal structure	19

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull NbB-07Pec · CALPHAD hull NbB-08Wit · CALPHAD hull NbB-08Yos · CALPHAD hull NbB-09Nak

Invariant reactions (literature)

Invariant reactions reported in the literature for the B–Nb system (32)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
3313	congruent melting: L <-> NbB2	L: B 0.66; NbB2: B 0.66	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 26 report
3308	congruent melting: L <-> NbB2	L: B 0.667; NbB2: B 0.667	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 27 report
3303	congruent melting: L <-> NbB2	L: B 0.659; NbB2: B 0.659	model	[1] Witusiewicz 2008	Table 5, p. 5, row 28 report
3273	congruent melting: L <-> NbB2	L: B 0.666; NbB2: B 0.666	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 25 report
3212	peritectic: L + NbB2 <-> Nb3B4	L: B 0.573; NbB2: B 0.61; Nb3B4: B 0.58	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 20 report
3194	congruent melting: L <-> NbB	L: B 0.5; NbB: B 0.5	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 12 report
3186	peritectic: L + NbB2 <-> Nb3B4	L: B 0.527; NbB2: B 0.61; Nb3B4: B 0.571	model	[1] Witusiewicz 2008	Table 5, p. 5, row 22 report
3176	congruent melting: L <-> NbB	L: B 0.499; NbB: B 0.499	model	[1] Witusiewicz 2008	Table 5, p. 5, row 13 report
3174.2	peritectic: L + Nb3B4 <-> Nb5B6	L: B 0.514; Nb3B4: B 0.571; Nb5B6: B 0.545	model	[1] Witusiewicz 2008	Table 5, p. 5, row 18 report
3174.1	eutectic: L <-> NbB + Nb5B6	L: B 0.514; NbB: B 0.499; Nb5B6: B 0.545	model	[1] Witusiewicz 2008	Table 5, p. 5, row 17 report
3169	peritectic: L + NbB2 <-> Nb3B4	L: B 0.582; NbB2: B 0.7; Nb3B4: B 0.571	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 21 report
3137	eutectic: L <-> NbB + Nb3B4	L: B 0.54; NbB: B 0.51; Nb3B4: B 0.575	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 15 report
3044	eutectic: L <-> NbB + Nb3B4	L: B 0.582; NbB: B 0.5; Nb3B4: B 0.571	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 16 report
3023	eutectic: L <-> NbB + Nb3B4	L: B 0.53; NbB: B 0.5; Nb3B4: B 0.57	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 14 report
2993	peritectic: L + NbB2 <-> Nb3B4	L: B 0.555; NbB2: B 0.64; Nb3B4: B 0.57	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 19 report
2650	peritectoid: Nb3B4 + NbB2 <-> Nb2B3	Nb3B4: B 0.571; NbB2: B 0.659; Nb2B3: B 0.6	model	[1] Witusiewicz 2008	Table 5, p. 5, row 24 report
2563	congruent melting: L <-> NbB	L: B 0.5; NbB: B 0.5	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 11 report
2463	eutectic: L <-> bcc + NbB	L: B 0.15; NbB: B 0.5, Nb 0.5	experimental	[1] Witusiewicz 2008	Table 5, p. 5, row 4 report
2453	eutectic: L <-> bcc + NbB	L: B 0.151; bcc: B 0.02; NbB: B 0.488	model	[1] Witusiewicz 2008	Table 5, p. 5, row 6 report
2443	eutectic: L <-> bcc + NbB	L: B 0.12; NbB: B 0.5, Nb 0.5	experimental	[1] Witusiewicz 2008 cites Pshokin 1971	Table 5, p. 5, row 3 report
2441	eutectic: L <-> bcc + NbB	L: B 0.19; bcc: B 0.02; NbB: B 0.49	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 2 report
2439	eutectic: L <-> bcc + NbB	L: B 0.151; bcc: B 0.005; NbB: B 0.5	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 5 report
2353	peritectoid: bcc + NbB <-> Nb3B2	bcc: B 0.009; NbB: B 0.5; Nb3B2: B 0.4	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 8 report
2350	peritectoid: bcc + NbB <-> Nb3B2	bcc: B 0.019; NbB: B 0.49; Nb3B2: B 0.4	model	[1] Witusiewicz 2008	Table 5, p. 5, row 10 report
2310	eutectic: L <-> NbB2 + (βB)	L: B 0.98; NbB2: B 0.7; (βB): B 0.995	experimental	[1] Witusiewicz 2008 cites Rudy 1969	Table 5, p. 5, row 30 report
2285	eutectic: L <-> NbB2 + (βB)	L: B 0.954; NbB2: B 0.703; (βB): B 0.995	model	[1] Witusiewicz 2008	Table 5, p. 5, row 32 report
2234	eutectic: L <-> NbB2 + (βB)	L: B 0.958; NbB2: B 0.7; (βB): B 1	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 31 report
2213	eutectic: L <-> NbB2 + (βB)	L: B 0.91; NbB2: B 0.74; (βB): B 0.975	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 29 report
2209	peritectoid: bcc + NbB <-> Nb3B2	bcc: B 0.003; NbB: B 0.5; Nb3B2: B 0.4	model	[1] Witusiewicz 2008 cites Kaufman 1984 doi	Table 5, p. 5, row 9 report
2113	peritectic: L + NbB <-> Nb3B2	L: B 0.385; NbB: B 0.5; Nb3B2: B 0.4	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 7 report
1973	other: ? <-> Nb2B3	?: B 0.6, Nb 0.4; Nb2B3: B 0.6, Nb 0.4	experimental	[1] Witusiewicz 2008 cites Okada 1991	Table 5, p. 5, row 23 report
1873	eutectic: L <-> bcc + Nb3B2	L: B 0.2; bcc: B 0.03; Nb3B2: B 0.4	experimental	[1] Witusiewicz 2008 cites Nowotny 1959	Table 5, p. 5, row 1 report

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, B–Nb system (8)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
NbB		-82.6 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 18 report
NbB		-82.4 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 17 report
NbB		-82.2 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 16 report
NbB		-79.4 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 15 report
NbB		-79.2 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 14 report
NbB		-78.7 kJ/mol-atom	0	DFT			[2] Nakama 2009	Table 4, p. 7, row 12 report
NbB	NbB	-78.7 kJ/mol-atom		model	-74.259 (mp-aaaaadvg)	-74.633 (oqmd-7942)	[2] Nakama 2009 cites Witusiewicz 2008 doi	Table 4, p. 7, row 13 report
NbB	NbB	-67.9 kJ/mol-atom		model	-74.259 (mp-aaaaadvg)	-74.633 (oqmd-7942)	[2] Nakama 2009 cites Witusiewicz 2008 doi	Table 4, p. 7, row 20 report

Other properties

Heat capacity / entropy / enthalpy (9)

Heat capacity / entropy / enthalpy, B–Nb system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: Entropy at 298.15 K	20.4 J/mol-atom/K	298.15	Nb3B2 alloy: Nb 0.6	experimental	[3] Peçanha 2007 cites Blinder 1991 doi	Table 4, p. 6, row 4 report
Entropy printed: Entropy at 298.15 K	19.88 J/mol-atom/K	298.15	Nb3B2 alloy: Nb 0.6	model	[3] Peçanha 2007	Table 4, p. 6, row 3 report
Entropy printed: Entropy at 298.15 K	17.3857 J/mol-atom/K	298.15	Nb3B4 alloy: Nb 0.428571	model	[3] Peçanha 2007	Table 4, p. 6, row 8 report
Entropy printed: Entropy at 298.15 K	17.3 J/mol-atom/K	298.15	Nb3B4 alloy: Nb 0.428571	experimental	[3] Peçanha 2007 cites Blinder 1991 doi	Table 4, p. 6, row 9 report
Entropy printed: Entropy at 298.15 K	17.8636 J/mol-atom/K	298.15	Nb5B6 alloy: Nb 0.454545	model	[3] Peçanha 2007	Table 4, p. 6, row 7 report
Entropy printed: Entropy at 298.15 K	19.05 J/mol-atom/K	298.15	NbB alloy: Nb 0.5	model	[3] Peçanha 2007	Table 4, p. 6, row 5 report
Entropy printed: Entropy at 298.15 K	19 J/mol-atom/K	298.15	NbB alloy: Nb 0.5	experimental	[3] Peçanha 2007 cites Blinder 1991 doi	Table 4, p. 6, row 6 report
Entropy printed: Entropy at 298.15 K	12.7 J/mol-atom/K	298.15	NbB2 alloy: Nb 0.333333	experimental	[3] Peçanha 2007 cites Westrum 1963 doi	Table 4, p. 6, row 2 report
Entropy printed: Entropy at 298.15 K	12.9 J/mol-atom/K	298.15	NbB2 alloy: Nb 0.333333	model	[3] Peçanha 2007	Table 4, p. 6, row 1 report

Crystal structure (19)

Crystal structure, B–Nb system
Property	T (K)	Phases / composition	Class	Source	Location
site fractional coordinates	298.15	BCC	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 1 report
site fractional coordinates	298.15	BCC	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 1 report
site fractional coordinates	298.15	Nb3B2 alloy: Nb 0.6	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 2 report
site fractional coordinates	298.15	Nb3B2 alloy: Nb 0.6	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 2 report
site fractional coordinates	298.15	Nb3B2 alloy: Nb 0.6	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 2 report
site fractional coordinates	298.15	Nb3B4 alloy: Nb 0.428571	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 5 report
site fractional coordinates	298.15	Nb3B4 alloy: Nb 0.428571	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 5 report
site fractional coordinates	298.15	Nb3B4 alloy: Nb 0.428571	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 5 report
site fractional coordinates	298.15	Nb3B4 alloy: Nb 0.428571	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 5 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	Nb5B6 alloy: Nb 0.454545	unspecified	[3] Peçanha 2007 cites Bolmgren 1990 doi	Table 1, p. 3, row 4 report
site fractional coordinates	298.15	NbB alloy: Nb 0.5	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 3 report
site fractional coordinates	298.15	NbB alloy: Nb 0.5	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 3 report
site fractional coordinates	298.15	NbB2 alloy: Nb 0.333333	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 6 report
site fractional coordinates	298.15	NbB2 alloy: Nb 0.333333	unspecified	[3] Peçanha 2007 cites Villars 1991	Table 1, p. 3, row 6 report

Sources

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

V.T. Witusiewicz, A.A. Bondar, U. Hecht, S. Rex, T.Ya. Velikanova, The Al–B–Nb–Ti system, Journal of Alloys and Compounds 448, 185-194 (2008). doi:10.1016/j.jallcom.2006.10.034
Yu Nakama, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of the Nb&ndash;Ti&ndash;B Ternary Phase Diagram, Mater. Trans. 50, 984-993 (2009). doi:10.2320/matertrans.mc200820
Rockfeller Maciel Peçanha, Flávio Ferreira, Gilberto Carvalho Coelho, Carlos Angelo Nunes, Bo Sundman, Thermodynamic modeling of the Nb–B system, Intermetallics 15, 999-1005 (2007). doi:10.1016/j.intermet.2006.10.054

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}
}