B–Mg system

93 accepted literature values from 2 paper(s) (experimental 56, model 37); 0 calculated phase diagram(s). 3 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · phases (10) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	56
model	37

Accepted values by property group
Property group	Values
invariant reaction	6
phase transition	17
formation	70

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull MgB-01Liu-LB

Invariant reactions (literature)

Invariant reactions reported in the literature for the B–Mg system (6)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
2423.15	Gas+Liquid=MgB7	MgB7: B 0.875, Mg 0.125; gas: B 1.000e-5; liq: B 0.991	model	[1] Liu 2001	Table 4, p. 4, row 1 report
2344.15	Liquid=MgB7+β-rho	MgB7: B 0.875, Mg 0.125; β-rho: B 1; liq: B 0.996	model	[1] Liu 2001	Table 4, p. 4, row 2 report
2008.15	Gas+MgB7=MgB4	MgB7: B 0.875, Mg 0.125; MgB4: B 0.8, Mg 0.2; gas: B 0	model	[1] Liu 2001	Table 4, p. 4, row 3 report
1818.15	Gas+MgB4=MgB2	MgB4: B 0.8, Mg 0.2; MgB2: B 0.666667, Mg 0.333333; gas: B 0	model	[1] Liu 2001	Table 4, p. 4, row 4 report
1367.15	Gas+MgB2=Liquid	MgB2: B 0.666667, Mg 0.333333; gas: B 0; liq: B 0.01	model	[1] Liu 2001	Table 4, p. 4, row 5 report
923.15	Liquid=hcp+MgB2	hcp: B 0; MgB2: B 0.666667, Mg 0.333333; liq: B 2.000e-4	model	[1] Liu 2001	Table 4, p. 4, row 6 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–Mg system (53)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
Mg2B	Mg2B	-14.23 kJ/mol-atom ± 0.84	298.15	experimental		24.127 (oqmd-751629)	[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 11 report
Mg4B		-19.53 kJ/mol-atom ± 1.39	298.15	experimental			[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 12 report
MgB12		-15.8 per mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 20 report
MgB12		-10.1 per mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 21 report
MgB12	MgB12	-10.07 kJ/mol-atom ± 0.9	298.15	experimental		-0.392 (oqmd-1454219)	[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 10 report
MgB2		-41.1 per mol-atom ± 2.2	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 1 report
MgB2	MgB2	-41.1 kJ/mol-atom ± 2.2	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 1 report
MgB2	MgB2	-35.9 kJ/mol-atom	298.15	model	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 2 report
MgB2		-35.9 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 2 report
MgB2	MgB2	-26.66 kJ/mol-atom ± 10	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[1] Liu 2001 cites Jansson 1984	Table 2, p. 2, row 1 report
MgB2		-26.6 per mol-atom ± 10	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 4 report
MgB2	MgB2	-26.6 kJ/mol-atom ± 10	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 4 report
MgB2	MgB2	-24 kJ/mol-atom	298.15	model	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 3 report
MgB2		-24 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 3 report
MgB2	MgB2	-18.6 kJ/mol-atom	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 6 report
MgB2		-18.6 per mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 6 report
MgB2	MgB2	-18.55 kJ/mol-atom ± 1.12	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 7 report
MgB2	MgB2	-17.2 kJ/mol-atom ± 1.4	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[2] Balducci 2005	Table 2, p. 4, row 5 report
MgB2		-17.2 per mol-atom ± 1.4	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 5 report
MgB2	MgB2	-17.17 kJ/mol-atom ± 1.39	298.15	experimental	-12.577 (mp-aaaaabdj)	-13.509 (oqmd-98302)	[1] Liu 2001 cites Jansson 1984	Table 2, p. 2, row 4 report
MgB20		-15.8 kJ/mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 20 report
MgB20		-10.1 kJ/mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 21 report
MgB20		-8.5 kJ/mol-atom ± 0.6	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 18 report
MgB20		-8.5 per mol-atom ± 0.6	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 18 report
MgB20		-7.8 kJ/mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 19 report
MgB20		-7.8 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 19 report
MgB4		-29.9 per mol-atom ± 2	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 7 report
MgB4	MgB4	-29.9 kJ/mol-atom ± 2	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 7 report
MgB4	MgB4	-25.5 kJ/mol-atom	298.15	model	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 8 report
MgB4		-25.5 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 8 report
MgB4		-18.4 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 9 report
MgB4	MgB4	-18.4 kJ/mol-atom	298.15	model	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 9 report
MgB4		-17.6 per mol-atom ± 3.8	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 10 report
MgB4	MgB4	-17.6 kJ/mol-atom ± 3.8	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 10 report
MgB4	MgB4	-17.57 kJ/mol-atom ± 3.85	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[1] Liu 2001 cites Jansson 1984	Table 2, p. 2, row 2 report
MgB4	MgB4	-14.73 kJ/mol-atom ± 0.5	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 8 report
MgB4		-14.7 per mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 12 report
MgB4	MgB4	-14.7 kJ/mol-atom	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 12 report
MgB4		-14.4 per mol-atom ± 0.8	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 11 report
MgB4	MgB4	-14.4 kJ/mol-atom ± 0.8	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[2] Balducci 2005	Table 2, p. 4, row 11 report
MgB4	MgB4	-14.39 kJ/mol-atom ± 0.75	298.15	experimental	-13.395 (mp-aaaaaaob)	-13.876 (oqmd-4315)	[1] Liu 2001 cites Jansson 1984	Table 2, p. 2, row 5 report
MgB6		-15.5 per mol-atom ± 2.1	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 15 report
MgB6		-13.4 per mol-atom	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 17 report
MgB6		-13.4 per mol-atom ± 0.6	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 16 report
MgB6	MgB6	-13.39 kJ/mol-atom ± 0.6	298.15	experimental		0.227 (oqmd-1454656)	[1] Liu 2001 cites Jansson 1984	Table 2, p. 2, row 6 report
MgB6	MgB6	-13.39 kJ/mol-atom ± 0.3	298.15	experimental		0.227 (oqmd-1454656)	[1] Liu 2001 cites Sundman 1985 doi	Table 2, p. 2, row 9 report
MgB7		-20.3 per mol-atom ± 1.5	298.15	experimental			[2] Balducci 2005	Table 2, p. 4, row 13 report
MgB7	MgB7	-20.3 kJ/mol-atom ± 1.5	298.15	experimental	-12.598 (mp-aaacdrdz)	-13.076 (oqmd-23820)	[2] Balducci 2005	Table 2, p. 4, row 13 report
MgB7		-18.9 per mol-atom	298.15	model			[2] Balducci 2005	Table 2, p. 4, row 14 report
MgB7	MgB7	-18.9 kJ/mol-atom	298.15	model	-12.598 (mp-aaacdrdz)	-13.076 (oqmd-23820)	[2] Balducci 2005	Table 2, p. 4, row 14 report
MgB7	MgB7	-15.5 kJ/mol-atom ± 2.1	298.15	experimental	-12.598 (mp-aaacdrdz)	-13.076 (oqmd-23820)	[2] Balducci 2005	Table 2, p. 4, row 15 report
MgB7	MgB7	-13.4 kJ/mol-atom	298.15	experimental	-12.598 (mp-aaacdrdz)	-13.076 (oqmd-23820)	[2] Balducci 2005	Table 2, p. 4, row 17 report
MgB7	MgB7	-13.4 kJ/mol-atom ± 0.6	298.15	experimental	-12.598 (mp-aaacdrdz)	-13.076 (oqmd-23820)	[2] Balducci 2005	Table 2, p. 4, row 16 report

Other properties

Phase transition (17)

Phase transition, B–Mg system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	1818 K	1818	other: MgB2 alloy: Mg 0.333333	model	[2] Balducci 2005	Table 4, p. 5, row 17 report
Phase transition	1818.15 K	1818.15	other	model	[1] Liu 2001	p. 2 report	Based on the limited experimental data in the literature[9, 10, 13], the suggestion by Spear[6], and the thermodynamic data of MgB2 and MgB4 in the JANAF table and by SGTE[18], the decomposition temperatures of the three intermediate compounds are estimated to be 1545, 1735, and 2150 °C for MgB2, MgB4, and MgB7, respectively.
Phase transition	1823 K	1823	other: MgB2 alloy: Mg 0.333333	model	[2] Balducci 2005	Table 4, p. 5, row 18 report
Phase transition	1888 K	1888	other: MgB2 alloy: Mg 0.333333	experimental	[2] Balducci 2005	Table 4, p. 5, row 15 report
Phase transition	1941 K	1941	other: MgB4 alloy: Mg 0.2	experimental	[2] Balducci 2005	Table 4, p. 5, row 19 report
Phase transition	1980 K	1980	other: MgB2 alloy: Mg 0.333333	model	[2] Balducci 2005	Table 4, p. 5, row 16 report
Phase transition	2008 K	2008	other: MgB4 alloy: Mg 0.2	model	[2] Balducci 2005	Table 4, p. 5, row 21 report
Phase transition	2008.15 K	2008.15	other	model	[1] Liu 2001	p. 2 report	Based on the limited experimental data in the literature[9, 10, 13], the suggestion by Spear[6], and the thermodynamic data of MgB2 and MgB4 in the JANAF table and by SGTE[18], the decomposition temperatures of the three intermediate compounds are estimated to be 1545, 1735, and 2150 °C for MgB2, MgB4, and MgB7, respectively.
Phase transition	2073 K	2073	other: MgB4 alloy: Mg 0.2	model	[2] Balducci 2005	Table 4, p. 5, row 22 report
Phase transition	2282 K	2282	other: MgB4 alloy: Mg 0.2	model	[2] Balducci 2005	Table 4, p. 5, row 20 report
Phase transition	2318 K	2318	other: MgB7 alloy: Mg 0.125	experimental	[2] Balducci 2005	Table 4, p. 5, row 23 report
Phase transition	2415 K	2415	other: MgB7 alloy: Mg 0.125	model	[2] Balducci 2005	Table 4, p. 5, row 24 report
Phase transition	2423 K	2423	other: MgB7 alloy: Mg 0.125	model	[2] Balducci 2005	Table 4, p. 5, row 25 report
Phase transition	2423.15 K	2423.15	other	model	[1] Liu 2001	p. 2 report	Based on the limited experimental data in the literature[9, 10, 13], the suggestion by Spear[6], and the thermodynamic data of MgB2 and MgB4 in the JANAF table and by SGTE[18], the decomposition temperatures of the three intermediate compounds are estimated to be 1545, 1735, and 2150 °C for MgB2, MgB4, and MgB7, respectively.
Phase transition	2464 K	2464	other: MgB20 alloy: Mg 0.047619	model	[2] Balducci 2005	Table 4, p. 5, row 27 report
Phase transition	2700 K	2700	other: MgB20 alloy: Mg 0.047619	experimental	[2] Balducci 2005	Table 4, p. 5, row 28 report
Phase transition	2759 K	2759	other: MgB20 alloy: Mg 0.047619	experimental	[2] Balducci 2005	Table 4, p. 5, row 26 report

Formation (17)

Formation, B–Mg system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy of formation printed: ΔfS0298	-2.8 per mol-atom ± 0.1	298.15	MgB2 alloy: Mg 0.333333	experimental	[2] Balducci 2005	Table 3, p. 4, row 4 report
Entropy of formation printed: ΔfS0298	-2.86 J/mol-atom/K	298.15	MgB2 alloy: Mg 0.333333	model	[2] Balducci 2005	Table 3, p. 4, row 2 report
Entropy of formation printed: ΔfS0298	-4.25 per mol-atom ± 0.5	298.15	MgB2 alloy: Mg 0.333333	experimental	[2] Balducci 2005	Table 3, p. 4, row 1 report
Entropy of formation printed: ΔfS0298	0.343 J/mol-atom/K	298.15	MgB2 alloy: Mg 0.333333	model	[2] Balducci 2005	Table 3, p. 4, row 3 report
Entropy of formation printed: ΔfS0298	-2.82 J/mol-atom/K	298.15	MgB2 alloy: Mg 0.333333	experimental	[2] Balducci 2005	Table 3, p. 4, row 5 report
Entropy of formation printed: ΔfS0298	0.03 per mol-atom ± 0.01	298.15	MgB20 alloy: Mg 0.047619	experimental	[2] Balducci 2005	Table 3, p. 4, row 15 report
Entropy of formation printed: ΔfS0298	0.04 J/mol-atom/K	298.15	MgB20 alloy: Mg 0.047619	model	[2] Balducci 2005	Table 3, p. 4, row 16 report
Entropy of formation printed: ΔfS0298	-0.47 per mol-atom ± 0.1	298.15	MgB20 alloy: Mg 0.047619	experimental	[2] Balducci 2005	Table 3, p. 4, row 17 report
Entropy of formation printed: ΔfS0298	0.655 J/mol-atom/K	298.15	MgB4 alloy: Mg 0.2	model	[2] Balducci 2005	Table 3, p. 4, row 8 report
Entropy of formation printed: ΔfS0298	-1.18 J/mol-atom/K	298.15	MgB4 alloy: Mg 0.2	model	[2] Balducci 2005	Table 3, p. 4, row 7 report
Entropy of formation printed: ΔfS0298	-1.32 J/mol-atom/K	298.15	MgB4 alloy: Mg 0.2	experimental	[2] Balducci 2005 cites Pan 1989 doi	Table 3, p. 4, row 10 report
Entropy of formation printed: ΔfS0298	-3.04 per mol-atom ± 0.5	298.15	MgB4 alloy: Mg 0.2	experimental	[2] Balducci 2005	Table 3, p. 4, row 6 report
Entropy of formation printed: ΔfS0298	-0.84 per mol-atom ± 0.1	298.15	MgB4 alloy: Mg 0.2	experimental	[2] Balducci 2005	Table 3, p. 4, row 9 report
Entropy of formation printed: ΔfS0298	-0.1 J/mol-atom/K	298.15	MgB7 alloy: Mg 0.125	model	[2] Balducci 2005	Table 3, p. 4, row 13 report
Entropy of formation printed: ΔfS0298	0.02 J/mol-atom/K	298.15	MgB7 alloy: Mg 0.125	experimental	[2] Balducci 2005 cites Pan 1989 doi	Table 3, p. 4, row 14 report
Entropy of formation printed: ΔfS0298	0.94 per mol-atom ± 0.5	298.15	MgB7 alloy: Mg 0.125	experimental	[2] Balducci 2005	Table 3, p. 4, row 11 report
Entropy of formation printed: ΔfS0298	-1.21 J/mol-atom/K	298.15	MgB7 alloy: Mg 0.125	model	[2] Balducci 2005	Table 3, p. 4, row 12 report

Sources

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

Zi-Kui Liu, Yu Zhong, D.G. Schlom, X.X. Xi, Qi Li, Computational thermodynamic modeling of the Mg-B system, Calphad 25, 299-303 (2001). doi:10.1016/s0364-5916(01)00050-5
G. Balducci, S. Brutti, A. Ciccioli, G. Gigli, P. Manfrinetti, A. Palenzona et al., Thermodynamics of the intermediate phases in the Mg–B system, Journal of Physics and Chemistry of Solids 66, 292-297 (2005). doi:10.1016/j.jpcs.2004.06.063

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}
}