# Gd–Ge system

> Gd–Ge system: 27 accepted literature values (invariant reaction 26, formation 1) and 1 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/GD-GE.html · Markdown: https://data.orchid-project.org/systems/GD-GE.md

27 accepted literature values from 1 paper(s) (experimental 13, model 13, unspecified 1); 1 calculated phase diagram(s). 14 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: [JSON](https://data.orchid-project.org/literature/systems/GD-GE.json) · [CSV](https://data.orchid-project.org/systems/GD-GE.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#GD-GE) · [interactive phase diagram](https://orchid-project.org/phase-diagrams/#GD-GE/GdGe-08Che.json) · [phases (14)](https://data.orchid-project.org/phases/pages/GD-GE.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/GD-GE.html) · [Markdown](https://data.orchid-project.org/systems/GD-GE.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 13 |
| model | 13 |
| unspecified | 1 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 26 |
| formation | 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.

Table: Assessments with a calculated phase diagram

| TDB file | Assessment | SHA-256 | Links |
|---|---|---|---|
| GdGe-08Che.tdb | H.-L. Chen, Y. Du, C.-Y. He, J. Alloys Compd., 462, 181-86(2008). [doi:10.1016/j.jallcom.2007.07.105](https://doi.org/10.1016/j.jallcom.2007.07.105) | `fc48e8e82696745edb2accb0d4c00d8c2ee9fa258e0b2a99316cf03fb94233ff` | [viewer](https://orchid-project.org/phase-diagrams/#GD-GE/GdGe-08Che.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/GdGe-08Che.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/GdGe-08Che.json) |

Table: Calculated three-phase invariants (model, mole fraction of the second component)

| TDB file | T (K) | Phases at the invariant |
|---|---:|---|
| GdGe-08Che.tdb | 1962.66 | GD5GE3_D88 (x(Ge) 0.375) + GD5GE4 (x(Ge) 0.44444) + LIQUID (x(Ge) 0.46006) |
| GdGe-08Che.tdb | 1962.66 | GD5GE3_D88 (x(Ge) 0.375) + GD5GE4 (x(Ge) 0.44444) + LIQUID (x(Ge) 0.45995) |
| GdGe-08Che.tdb | 1962.66 | GD5GE3_D88 (x(Ge) 0.375) + GD5GE4 (x(Ge) 0.44444) + LIQUID (x(Ge) 0.4602) |
| GdGe-08Che.tdb | 1843.96 | GD5GE4 (x(Ge) 0.44444) + GDGE_B33 (x(Ge) 0.5) + LIQUID (x(Ge) 0.5392) |
| GdGe-08Che.tdb | 1843.96 | GD5GE4 (x(Ge) 0.44444) + GDGE_B33 (x(Ge) 0.5) + LIQUID (x(Ge) 0.53928) |
| GdGe-08Che.tdb | 1843.96 | GD5GE4 (x(Ge) 0.44444) + GDGE_B33 (x(Ge) 0.5) + LIQUID (x(Ge) 0.53889) |
| GdGe-08Che.tdb | 1687.12 | GDGE_B33 (x(Ge) 0.5) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.62176) |
| GdGe-08Che.tdb | 1687.12 | GDGE_B33 (x(Ge) 0.5) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.62167) |
| GdGe-08Che.tdb | 1687.12 | GDGE_B33 (x(Ge) 0.5) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.62162) |
| GdGe-08Che.tdb | 1508.16 | HCP_A3 (x(Ge) 0) + BCC_A2 (x(Ge) 0) + LIQUID (x(Ge) 0.03879) |
| GdGe-08Che.tdb | 1483.24 | GDGE_B33 (x(Ge) 0.5) + GD2GE3_BETA (x(Ge) 0.59) + GD2GE3_GAMMA (x(Ge) 0.6) |
| GdGe-08Che.tdb | 1386.04 | HCP_A3 (x(Ge) 0) + LIQUID (x(Ge) 0.09693) + GD5GE3_D88 (x(Ge) 0.375) |
| GdGe-08Che.tdb | 1342.95 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.77293) |
| GdGe-08Che.tdb | 1342.95 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.77293) |
| GdGe-08Che.tdb | 1342.95 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE3_GAMMA (x(Ge) 0.6) + LIQUID (x(Ge) 0.77287) |
| GdGe-08Che.tdb | 1163.07 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE5 (x(Ge) 0.71989) + LIQUID (x(Ge) 0.83496) |
| GdGe-08Che.tdb | 1163.07 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE5 (x(Ge) 0.71989) + LIQUID (x(Ge) 0.83484) |
| GdGe-08Che.tdb | 1132.59 | GD2GE5 (x(Ge) 0.71989) + LIQUID (x(Ge) 0.84862) + DIAMOND_A4 (x(Ge) 1) |
| GdGe-08Che.tdb | 1132.59 | GD2GE5 (x(Ge) 0.71989) + LIQUID (x(Ge) 0.84855) + DIAMOND_A4 (x(Ge) 1) |
| GdGe-08Che.tdb | 1122.89 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE5 (x(Ge) 0.71989) + DIAMOND_A4 (x(Ge) 1) |
| GdGe-08Che.tdb | 1106.03 | GDGE_B33 (x(Ge) 0.5) + GD2GE3_C32 (x(Ge) 0.59) + GD2GE3_BETA (x(Ge) 0.59) |
| GdGe-08Che.tdb | 1106.03 | GD2GE3_BETA (x(Ge) 0.59) + GD2GE3_C32 (x(Ge) 0.59) + DIAMOND_A4 (x(Ge) 1) |
| GdGe-08Che.tdb | 1080.44 | GD2GE3_C32 (x(Ge) 0.59) + GD3GE5_BETA (x(Ge) 0.625) + DIAMOND_A4 (x(Ge) 1) |
| GdGe-08Che.tdb | 872 | GD2GE3_C32 (x(Ge) 0.59) + GD3GE5_CC (x(Ge) 0.625) + GD3GE5_BETA (x(Ge) 0.625) |
| GdGe-08Che.tdb | 872 | GD3GE5_BETA (x(Ge) 0.625) + GD3GE5_CC (x(Ge) 0.625) + DIAMOND_A4 (x(Ge) 1) |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/GD/GD-GE.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/GD/GD-GE.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the Gd–Ge system (26)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 2063 | congruent melting: L -> Gd5Ge3 | L: Gd 0.625, Ge 0.375; Gd5Ge3: Gd 0.625, Ge 0.375 | model | [1] Chen 2008 | Table 2, p. 5, row 4; `ORC-3YM6JHJZX3` |  |
| 2063 | congruent melting: L -> Gd5Ge3 | L: Gd 0.625, Ge 0.375; Gd5Ge3: Gd 0.625, Ge 0.375 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 3; `ORC-YAITKNUDNH` |  |
| 1963 | L + Gd5Ge3 -> Gd5Ge4 | Gd5Ge3: Gd 0.625, Ge 0.375; Gd5Ge4: Gd 0.555556, Ge 0.444444 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 5; `ORC-75T43SHD35` |  |
| 1963 | L + Gd5Ge3 -> Gd5Ge4 | Gd5Ge3: Gd 0.625, Ge 0.375; Gd5Ge4: Gd 0.555556, Ge 0.444444 | model | [1] Chen 2008 | Table 2, p. 5, row 6; `ORC-JIAOPIKJXW` |  |
| 1844 | L + Gd5Ge4 -> GdGe | Gd5Ge4: Gd 0.555556, Ge 0.444444; GdGe: Gd 0.5, Ge 0.5 | model | [1] Chen 2008 | Table 2, p. 5, row 8; `ORC-OPBIMMPT7Q` |  |
| 1843 | L + Gd5Ge4 -> GdGe | Gd5Ge4: Gd 0.555556, Ge 0.444444; GdGe: Gd 0.5, Ge 0.5 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 7; `ORC-DLPOYBO2CE` |  |
| 1688 | L + GdGe -> γ-Gd2Ge3 | GdGe: Gd 0.5, Ge 0.5; γ-Gd2Ge3: Gd 0.4, Ge 0.6 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 9; `ORC-X53IUZ5RF2` |  |
| 1687 | L + GdGe -> γ-Gd2Ge3 | GdGe: Gd 0.5, Ge 0.5; γ-Gd2Ge3: Gd 0.4, Ge 0.6 | model | [1] Chen 2008 | Table 2, p. 5, row 10; `ORC-ATKJ3ZPVUA` |  |
| 1483 | γ-Gd2Ge3 + GdGe -> β-Gd2Ge3 | γ-Gd2Ge3: Gd 0.4, Ge 0.6; GdGe: Gd 0.5, Ge 0.5; β-Gd2Ge3: Gd 0.41, Ge 0.59 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 11; `ORC-62DIQ2FIR7` |  |
| 1483 | γ-Gd2Ge3 + GdGe -> β-Gd2Ge3 | γ-Gd2Ge3: Gd 0.4, Ge 0.6; GdGe: Gd 0.5, Ge 0.5; β-Gd2Ge3: Gd 0.41, Ge 0.59 | model | [1] Chen 2008 | Table 2, p. 5, row 12; `ORC-GK4L4UUNW2` |  |
| 1386 | eutectic: L -> α-Gd + Gd5Ge3 | Gd5Ge3: Gd 0.625, Ge 0.375 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 1; `ORC-76NURQZJ4J` |  |
| 1386 | eutectic: L -> α-Gd + Gd5Ge3 | Gd5Ge3: Gd 0.625, Ge 0.375 | model | [1] Chen 2008 | Table 2, p. 5, row 2; `ORC-IYD53TG4H5` |  |
| 1343 | γ-Gd2Ge3 -> β-Gd2Ge3 + L | γ-Gd2Ge3: Gd 0.4, Ge 0.6; β-Gd2Ge3: Gd 0.41, Ge 0.59 | model | [1] Chen 2008 | Table 2, p. 5, row 14; `ORC-BIJIMPOLAF` |  |
| 1343 | γ-Gd2Ge3 -> β-Gd2Ge3 + L | γ-Gd2Ge3: Gd 0.4, Ge 0.6; β-Gd2Ge3: Gd 0.41, Ge 0.59 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 13; `ORC-EVK34Z2MRN` |  |
| 1163 | β-Gd2Ge3 + L -> GdGe2.57 | β-Gd2Ge3: Gd 0.41, Ge 0.59; GdGe2.57: Gd 0.280112, Ge 0.719888 | model | [1] Chen 2008 | Table 2, p. 5, row 16; `ORC-FDIWPISMRG` |  |
| 1163 | β-Gd2Ge3 + L -> GdGe2.57 | β-Gd2Ge3: Gd 0.41, Ge 0.59; GdGe2.57: Gd 0.280112, Ge 0.719888 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 15; `ORC-W2QZISNQG3` |  |
| 1133 | eutectic: L -> GdGe2.57 + Ge | GdGe2.57: Gd 0.280112, Ge 0.719888 | model | [1] Chen 2008 | Table 2, p. 5, row 18; `ORC-UWZKWTY56W` |  |
| 1133 | eutectic: L -> GdGe2.57 + Ge | GdGe2.57: Gd 0.280112, Ge 0.719888 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 17; `ORC-WGQSX2UIEW` |  |
| 1123 | GdGe2.57 -> β-Gd2Ge3 + Ge | GdGe2.57: Gd 0.280112, Ge 0.719888; β-Gd2Ge3: Gd 0.41, Ge 0.59 | model | [1] Chen 2008 | Table 2, p. 5, row 20; `ORC-2STZRRR6ZH` |  |
| 1123 | GdGe2.57 -> β-Gd2Ge3 + Ge | GdGe2.57: Gd 0.280112, Ge 0.719888; β-Gd2Ge3: Gd 0.41, Ge 0.59 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 19; `ORC-GSX656ENZ6` |  |
| 1106 | polymorphic: β-Gd2Ge3 -> α-Gd2Ge3 | β-Gd2Ge3: Gd 0.41, Ge 0.59; α-Gd2Ge3: Gd 0.41, Ge 0.59 | model | [1] Chen 2008 | Table 2, p. 5, row 22; `ORC-L6TI43CQTO` |  |
| 1106 | polymorphic: β-Gd2Ge3 -> α-Gd2Ge3 | β-Gd2Ge3: Gd 0.41, Ge 0.59; α-Gd2Ge3: Gd 0.41, Ge 0.59 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 21; `ORC-RIGDWXY3H7` |  |
| 1081 | α-Gd2Ge3 + Ge -> β-Gd5Ge3 | α-Gd2Ge3: Gd 0.41, Ge 0.59; β-Gd5Ge3: Gd 0.625, Ge 0.375 | experimental | [1] Chen 2008; _cites Eremenko 1980_ [doi](https://doi.org/10.1007/bf00792035) | Table 2, p. 5, row 23; `ORC-QWSFLZPNRH` |  |
| 1080 | α-Gd2Ge3 + Ge -> β-Gd5Ge3 | α-Gd2Ge3: Gd 0.41, Ge 0.59; β-Gd5Ge3: Gd 0.625, Ge 0.375 | model | [1] Chen 2008 | Table 2, p. 5, row 24; `ORC-QMBS23NHXF` |  |
| 873 | polymorphic: β-Gd5Ge3 -> α-Gd5Ge3 | β-Gd5Ge3: Gd 0.625, Ge 0.375 | unspecified | [1] Chen 2008; _cites Gokhale 1989_ [doi](https://doi.org/10.1007/bf02881428) | Table 2, p. 5, row 25; `ORC-BUNWMBTOOS` |  |
| 872 | polymorphic: β-Gd5Ge3 -> α-Gd5Ge3 | β-Gd5Ge3: Gd 0.625, Ge 0.375 | model | [1] Chen 2008 | Table 2, p. 5, row 26; `ORC-6TIA3UKIGM` |  |

## 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](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, Gd–Ge system (1)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| Gd5Ge3 |  | -82 unspecified ± 2.6 | 298.15 | experimental |  |  | [1] Chen 2008; _cites Meschel 1995_ [doi](https://doi.org/10.1016/0925-8388%2894%2901342-x) | p. 2; `ORC-PQJ3TWE7LT` | “Using direct-synthesis calorimetry, Meschel and Kleppa \[27\] determined the standard enthalpy of formation of Gd5 Ge3 to be -82.0 ± 2.6 kJ/mol-atoms at 1473 ± 2 K.” |

## Sources

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

1. Hai-Lin Chen, Yong Du, Cui-Yun He, Thermodynamic modeling of the gadolinium–germanium system, Journal of Alloys and Compounds 462, 181-186 (2008). [doi:10.1016/j.jallcom.2007.07.105](https://doi.org/10.1016/j.jallcom.2007.07.105)

## 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). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). https://doi.org/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). https://doi.org/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). https://doi.org/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.

```bibtex
@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}
}
```

---

Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\<id>, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).