Ca–Ge system

50 accepted literature values from 1 paper(s) (experimental 21, model 24, DFT 5); 1 calculated phase diagram(s). 7 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	21
model	24
DFT	5

Accepted values by property group
Property group	Values
invariant reaction	15
phase transition	7
formation	19
activity / EMF / Gibbs energy	9

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
CaGe-10Dja.tdb	Y. Djaballah, A. Pasturel, A. Belgacem-Bouzida, J. Alloys Compd., 497, 74-79(2010). doi:10.1016/j.jallcom.2010.02.189	`cb8f461fa9247dd95d26913b91736503e7ccb96dfcb54222eba9e42e0c08a7c5`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
CaGe-10Dja.tdb	1505.68	CA2GE_C37 (x(Ge) 0.33333) + CA5GE3_D8L (x(Ge) 0.375) + LIQUID (x(Ge) 0.42449)
CaGe-10Dja.tdb	1505.68	CA2GE_C37 (x(Ge) 0.33333) + CA5GE3_D8L (x(Ge) 0.375) + LIQUID (x(Ge) 0.42452)
CaGe-10Dja.tdb	1505.68	CA2GE_C37 (x(Ge) 0.33333) + CA5GE3_D8L (x(Ge) 0.375) + LIQUID (x(Ge) 0.42446)
CaGe-10Dja.tdb	1441.44	CA5GE3_D8L (x(Ge) 0.375) + CA7GE6 (x(Ge) 0.46154) + LIQUID (x(Ge) 0.46824)
CaGe-10Dja.tdb	1441.43	CA5GE3_D8L (x(Ge) 0.375) + CA7GE6 (x(Ge) 0.46154) + LIQUID (x(Ge) 0.46847)
CaGe-10Dja.tdb	1441.43	CA5GE3_D8L (x(Ge) 0.375) + CA7GE6 (x(Ge) 0.46154) + LIQUID (x(Ge) 0.46848)
CaGe-10Dja.tdb	1439.85	CA7GE6 (x(Ge) 0.46154) + LIQUID (x(Ge) 0.47548) + CAGE_B33 (x(Ge) 0.5)
CaGe-10Dja.tdb	1439.85	CA7GE6 (x(Ge) 0.46154) + LIQUID (x(Ge) 0.47571) + CAGE_B33 (x(Ge) 0.5)
CaGe-10Dja.tdb	1114.73	CAGE_B33 (x(Ge) 0.5) + LIQUID (x(Ge) 0.65452) + CAGE2_C12 (x(Ge) 0.66667)
CaGe-10Dja.tdb	1114.73	CAGE_B33 (x(Ge) 0.5) + LIQUID (x(Ge) 0.65441) + CAGE2_C12 (x(Ge) 0.66667)
CaGe-10Dja.tdb	1049.96	BCC_A2 (x(Ge) 0) + LIQUID (x(Ge) 0.02846) + CA2GE_C37 (x(Ge) 0.33333)
CaGe-10Dja.tdb	1045.38	CAGE2_C12 (x(Ge) 0.66667) + LIQUID (x(Ge) 0.77858) + DIAMOND_A4 (x(Ge) 1)
CaGe-10Dja.tdb	1045.38	CAGE2_C12 (x(Ge) 0.66667) + LIQUID (x(Ge) 0.7786) + DIAMOND_A4 (x(Ge) 1)
CaGe-10Dja.tdb	716.03	BCC_A2 (x(Ge) 0) + FCC_A1 (x(Ge) 0) + CA2GE_C37 (x(Ge) 0.33333)

Convex hulls: Materials Project DFT hull · OQMD DFT hull

Invariant reactions (literature)

Invariant reactions reported in the literature for the Ca–Ge system (15)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
1513	Liq + Ca2Ge ↔ Ca5Ge3	Liq: Ge 0.4; Ca2Ge: Ge 0.3333; Ca5Ge3: Ge 0.375	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 7 report
1505.59	Liq + Ca2Ge ↔ Ca5Ge3	Liq: Ge 0.4245; Ca2Ge: Ge 0.3333; Ca5Ge3: Ge 0.375	model	[1] Djaballah 2010	Table 2, p. 4, row 8 report
1443	Liq + Ca5Ge3 ↔ Ca7Ge6	Liq: Ge 0.462; Ca5Ge3: Ge 0.375; Ca7Ge6: Ge 0.46	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 9 report
1440.6	Liq + Ca5Ge3 ↔ Ca7Ge6	Liq: Ge 0.4688; Ca5Ge3: Ge 0.375; Ca7Ge6: Ge 0.46	model	[1] Djaballah 2010	Table 2, p. 4, row 10 report
1439.19	Liq ↔ Ca7Ge6 + CaGe	Liq: Ge 0.4744; Ca7Ge6: Ge 0.46; CaGe: Ge 0.5	model	[1] Djaballah 2010	Table 2, p. 4, row 12 report
1428	Liq ↔ Ca7Ge6 + CaGe	Liq: Ge 0.474; Ca7Ge6: Ge 0.46; CaGe: Ge 0.5	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 11 report
1115.82	Liq ↔ CaGe + CaGe2	Liq: Ge 0.6543; CaGe: Ge 0.5; CaGe2: Ge 0.6666	model	[1] Djaballah 2010	Table 2, p. 4, row 17 report
1113	Liq ↔ CaGe + CaGe2	Liq: Ge 0.654; CaGe: Ge 0.5; CaGe2: Ge 0.6666	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 16 report
1103	Liq ↔ CaGe + CaGe2	Liq: Ge 0.71; CaGe: Ge 0.5; CaGe2: Ge 0.6666	experimental	[1] Djaballah 2010 cites Massalski 1990	Table 2, p. 4, row 15 report
1073	Liq ↔ βCa + Ca2Ge	Liq: Ge 0.026; βCa: Ge 0; Ca2Ge: Ge 0.3333	experimental	[1] Djaballah 2010 cites Massalski 1990	Table 2, p. 4, row 1 report
1053	Liq ↔ βCa + Ca2Ge	Liq: Ge 0.032; βCa: Ge 0; Ca2Ge: Ge 0.3333	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 2 report
1050.13	Liq ↔ βCa + Ca2Ge	Liq: Ge 0.0282; βCa: Ge 0; Ca2Ge: Ge 0.3333	model	[1] Djaballah 2010	Table 2, p. 4, row 3 report
1046.22	Liq ↔ CaGe2 + Ge	Liq: Ge 0.779; CaGe2: Ge 0.6666; Ge: Ge 1	model	[1] Djaballah 2010	Table 2, p. 4, row 22 report
1033	Liq ↔ CaGe2 + Ge	Liq: Ge 0.76; CaGe2: Ge 0.6666; Ge: Ge 1	experimental	[1] Djaballah 2010 cites Massalski 1990	Table 2, p. 4, row 20 report
1018	Liq ↔ CaGe2 + Ge	Liq: Ge 0.759; CaGe2: Ge 0.6666; Ge: Ge 1	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 21 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, Ca–Ge system (19)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location
Ca2Ge		-58.9 kJ/mol-atom	1000	DFT			[1] Djaballah 2010 cites Yang 2010 doi	Table 3, p. 5, row 2 report
Ca2Ge	Ca2Ge	-56.14 kJ/mol-atom	1000	model	-59.236 (mp-aaaaaals)	-60.522 (oqmd-7763)	[1] Djaballah 2010 cites F 1988	Table 3, p. 5, row 3 report
Ca2Ge	Ca2Ge	-55.1 kJ/mol-atom	1000	model	-59.236 (mp-aaaaaals)	-60.522 (oqmd-7763)	[1] Djaballah 2010	Table 3, p. 5, row 4 report
Ca5Ge3	Ca5Ge3	-65.3 kJ/mol-atom ± 5.7	1000	experimental	-60.591 (mp-aaaaacum)	-61.726 (oqmd-7694)	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 5 report
Ca5Ge3	Ca5Ge3	-62.59 kJ/mol-atom	1000	model	-60.591 (mp-aaaaacum)	-61.726 (oqmd-7694)	[1] Djaballah 2010 cites F 1988	Table 3, p. 5, row 7 report
Ca5Ge3		-60.4 kJ/mol-atom	1000	DFT			[1] Djaballah 2010 cites Yang 2010 doi	Table 3, p. 5, row 6 report
Ca5Ge3	Ca5Ge3	-59.8 kJ/mol-atom	1000	model	-60.591 (mp-aaaaacum)	-61.726 (oqmd-7694)	[1] Djaballah 2010	Table 3, p. 5, row 8 report
Ca7Ge6	Ca7Ge6	-73.34 kJ/mol-atom	1000	model	-61.36 (mp-aaaaaynj)	-62.5 (oqmd-83101)	[1] Djaballah 2010 cites F 1988	Table 3, p. 5, row 10 report
Ca7Ge6	Ca7Ge6	-66.9 kJ/mol-atom	1000	model	-61.36 (mp-aaaaaynj)	-62.5 (oqmd-83101)	[1] Djaballah 2010	Table 3, p. 5, row 11 report
Ca7Ge6		-61.4 kJ/mol-atom	1000	DFT			[1] Djaballah 2010 cites Yang 2010 doi	Table 3, p. 5, row 9 report
CaGe	CaGe	-76.3627 kJ/mol-atom	1000	model	-63.815 (mp-aaaaadmu)	-64.906 (oqmd-7940)	[1] Djaballah 2010 cites F 1988	Table 3, p. 5, row 21 report
CaGe	CaGe	-67.8 kJ/mol-atom ± 2.8	1000	experimental	-63.815 (mp-aaaaadmu)	-64.906 (oqmd-7940)	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 12 report
CaGe		-64.3 kJ/mol-atom	1000	DFT			[1] Djaballah 2010 cites Yang 2010 doi	Table 3, p. 5, row 14 report
CaGe	CaGe	-63.9 kJ/mol-atom	1000	model	-63.815 (mp-aaaaadmu)	-64.906 (oqmd-7940)	[1] Djaballah 2010	Table 3, p. 5, row 16 report
CaGe	CaGe	-57.5 kJ/mol-atom ± 10	1000	experimental	-63.815 (mp-aaaaadmu)	-64.906 (oqmd-7940)	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 13 report
CaGe2	CaGe2	-70.11 kJ/mol-atom	1000	model	-46.529 (mp-aaabghlg)	-47.72 (oqmd-13940)	[1] Djaballah 2010 cites F 1988	Table 3, p. 5, row 19 report
CaGe2	CaGe2	-49.7 kJ/mol-atom ± 1.9	1000	experimental	-46.529 (mp-aaabghlg)	-47.72 (oqmd-13940)	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 17 report
CaGe2	CaGe2	-48.5 kJ/mol-atom	1000	model	-46.529 (mp-aaabghlg)	-47.72 (oqmd-13940)	[1] Djaballah 2010	Table 3, p. 5, row 20 report
CaGe2		-46.8 kJ/mol-atom	1000	DFT			[1] Djaballah 2010 cites Yang 2010 doi	Table 3, p. 5, row 18 report

Other properties

Phase transition (7)

Phase transition, Ca–Ge system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Phase transition	1117.35 K	1117.35	Liq ↔ CaGe2 Liq: Ge 0.6666; CaGe2: Ge 0.6666	model	[1] Djaballah 2010	Table 2, p. 4, row 19 report
Phase transition	1118 K	1118	Liq ↔ CaGe2 Liq: Ge 0.6666; CaGe2: Ge 0.6666	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 18 report
Phase transition	1447.7 K	1447.7	Liq ↔ CaGe Liq: Ge 0.5; CaGe: Ge 0.5	model	[1] Djaballah 2010	Table 2, p. 4, row 14 report
Phase transition	1483 K	1483	Liq ↔ CaGe Liq: Ge 0.5; CaGe: Ge 0.5	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 13 report
Phase transition	1579.6 K	1579.6	Liq ↔ Ca2Ge Liq: Ge 0.3333; Ca2Ge: Ge 0.3333	model	[1] Djaballah 2010	Table 2, p. 4, row 6 report
Phase transition	1583 K	1583	Liq ↔ Ca2Ge Liq: Ge 0.3333; Ca2Ge: Ge 0.3333	experimental	[1] Djaballah 2010 cites Palenzona 2002 doi	Table 2, p. 4, row 5 report
Phase transition	1653 K	1653	Liq ↔ Ca2Ge Liq: Ge 0.3333; Ca2Ge: Ge 0.3333	experimental	[1] Djaballah 2010 cites Massalski 1990	Table 2, p. 4, row 4 report

Activity / EMF / Gibbs energy (9)

Activity / EMF / Gibbs energy, Ca–Ge system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Gibbs energy	-60.5 kJ/mol ± 3.6	1000	Ca2Ge alloy: Ge 0.333333	experimental	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 1 report
Gibbs energy	-57.93 kJ/mol	1000	Ca2Ge alloy: Ge 0.333333	model	[1] Djaballah 2010	Table 3, p. 5, row 4 report
Gibbs energy	-62.6 kJ/mol ± 2.7	1000	Ca5Ge3 alloy: Ge 0.375	experimental	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 5 report
Gibbs energy	-59.61 kJ/mol	1000	Ca5Ge3 alloy: Ge 0.375	model	[1] Djaballah 2010	Table 3, p. 5, row 8 report
Gibbs energy	-61.13 kJ/mol	1000	Ca7Ge6 alloy: Ge 0.461538	model	[1] Djaballah 2010	Table 3, p. 5, row 11 report
Gibbs energy	-62.8 kJ/mol ± 1	1000	CaGe alloy: Ge 0.5	experimental	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 12 report
Gibbs energy	-59.83 kJ/mol	1000	CaGe alloy: Ge 0.5	model	[1] Djaballah 2010	Table 3, p. 5, row 16 report
Gibbs energy	-44.02 kJ/mol	1000	CaGe2 alloy: Ge 0.666667	model	[1] Djaballah 2010	Table 3, p. 5, row 20 report
Gibbs energy	-47.2 kJ/mol ± 0.7	1000	CaGe2 alloy: Ge 0.666667	experimental	[1] Djaballah 2010 cites Mejbar 1993	Table 3, p. 5, row 17 report

Sources

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

Y. Djaballah, A. Pasturel, A. Belgacem-Bouzida, Thermodynamic assessment of the calcium–germanium system, Journal of Alloys and Compounds 497, 74-79 (2010). doi:10.1016/j.jallcom.2010.02.189

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}
}