# Cu–S system

> Cu–S system: 23 accepted literature values (invariant reaction 19, phase transition 4) and 3 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/CU-S.html · Markdown: https://data.orchid-project.org/systems/CU-S.md

23 accepted literature values from 1 paper(s) (experimental 12, model 11); 3 calculated phase diagram(s). 12 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/CU-S.json) · [CSV](https://data.orchid-project.org/systems/CU-S.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#CU-S) · [interactive phase diagram](https://orchid-project.org/phase-diagrams/#CU-S/CuS-07Lee.json) · [phases (14)](https://data.orchid-project.org/phases/pages/CU-S.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/CU-S.html) · [Markdown](https://data.orchid-project.org/systems/CU-S.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 12 |
| model | 11 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 19 |
| phase transition | 4 |

## 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 |
|---|---|---|---|
| CuS-07Lee.tdb | B.-J. Lee, B. Sundman, S.I. Kim, K.-G. Chin, ISIJ Int., 47, 163-71(2007). [doi:10.2355/isijinternational.47.163](https://doi.org/10.2355/isijinternational.47.163) | `d5d1065a84e9aabe84f1a0d2ad1ffe56d89e9dbc799ad90b44c16f840b0275a0` | [viewer](https://orchid-project.org/phase-diagrams/#CU-S/CuS-07Lee.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/CuS-07Lee.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/CuS-07Lee.json) |
| CuS-92Sun-LB.tdb | B. Sundman, unpublished, 1992. | `b8d5ff92c7cc3e8388cd43eed138d371e60c79cb9b044dfda0d7c3328bcb0726` | [viewer](https://orchid-project.org/phase-diagrams/#CU-S/CuS-92Sun-LB.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/CuS-92Sun-LB.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/CuS-92Sun-LB.json) |
| CuS-92Sun-newS.tdb | B. Sundman, unpublished, 1992. | `137242d5bf305aadb1a044623c566cbe19778f1612775076add29b4808d1b3ff` | [viewer](https://orchid-project.org/phase-diagrams/#CU-S/CuS-92Sun-newS.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/CuS-92Sun-newS.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/CuS-92Sun-newS.json) |

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

| TDB file | T (K) | Phases at the invariant |
|---|---:|---|
| CuS-07Lee.tdb | 1409.44 | LIQUID#2 (x(S) 0.022) + LIQUID (x(S) 0.33136) + CU2S_GAMMA (x(S) 0.33301) |
| CuS-07Lee.tdb | 1342.28 | FCC_A1 (x(S) 2.300e-4) + LIQUID (x(S) 0.0141) + CU2S_GAMMA (x(S) 0.33314) |
| CuS-07Lee.tdb | 1236.55 | CU2S_GAMMA (x(S) 0.34888) + LIQUID (x(S) 0.37241) + GAS (x(S) 1) |
| CuS-07Lee.tdb | 766.66 | CU2S_GAMMA (x(S) 0.36861) + CUS_B18 (x(S) 0.5) + GAS (x(S) 1) |
| CuS-07Lee.tdb | 723.86 | CUS_B18 (x(S) 0.5) + LIQUID (x(S) 0.99996) + GAS (x(S) 1) |
| CuS-07Lee.tdb | 707.74 | FCC_A1 (x(S) 0) + CU2S_BETA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.33342) |
| CuS-07Lee.tdb | 384.34 | CUS_B18 (x(S) 0.5) + ORTHORHOMBIC_A16 (x(S) 1) + LIQUID (x(S) 1) |
| CuS-07Lee.tdb | 379.45 | FCC_A1 (x(S) 0) + CU2S_ALPHA (x(S) 0.33333) + CU2S_BETA (x(S) 0.33333) |
| CuS-07Lee.tdb | 379.45 | CU2S_BETA (x(S) 0.33333) + CU2S_ALPHA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.35194) |
| CuS-07Lee.tdb | 367.17 | CU2S_ALPHA (x(S) 0.33333) + CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.35287) |
| CuS-07Lee.tdb | 350.02 | CU2S_GAMMA (x(S) 0.35915) + CU7S4 (x(S) 0.36364) + CUS_B18 (x(S) 0.5) |
| CuS-07Lee.tdb | 343.58 | CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.35609) + CU7S4 (x(S) 0.36364) |
| CuS-92Sun-LB.tdb | 1377.51 | ION#2 (x(S) 0.02066) + ION (x(S) 0.32881) + CU2S_GAMMA (x(S) 0.33312) |
| CuS-92Sun-LB.tdb | 1338.66 | FCC_A1 (x(S) 1.900e-4) + ION (x(S) 0.01729) + CU2S_GAMMA (x(S) 0.33317) |
| CuS-92Sun-LB.tdb | 779.75 | CU2S_GAMMA (x(S) 0.36474) + CUS_B18 (x(S) 0.5) + LIQUID (x(S) 0.99983) |
| CuS-92Sun-LB.tdb | 710.34 | FCC_A1 (x(S) 0) + CU2S_BETA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.33341) |
| CuS-92Sun-LB.tdb | 388.35 | CUS_B18 (x(S) 0.5) + MONOCLINIC_S (x(S) 1) + LIQUID (x(S) 1) |
| CuS-92Sun-LB.tdb | 375.97 | FCC_A1 (x(S) 0) + CU2S_ALPHA (x(S) 0.33333) + CU2S_BETA (x(S) 0.33333) |
| CuS-92Sun-LB.tdb | 375.97 | CU2S_BETA (x(S) 0.33333) + CU2S_ALPHA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.34555) |
| CuS-92Sun-LB.tdb | 371.96 | CU2S_ALPHA (x(S) 0.33333) + CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.34634) |
| CuS-92Sun-LB.tdb | 368.33 | CUS_B18 (x(S) 0.5) + ORTHORHOMBIC_A16 (x(S) 1) + MONOCLINIC_S (x(S) 1) |
| CuS-92Sun-LB.tdb | 325.41 | CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.35752) + CUS_B18 (x(S) 0.5) |
| CuS-92Sun-LB.tdb | 311.97 | CU31S16 (x(S) 0.3413) + CU7S4 (x(S) 0.36364) + CUS_B18 (x(S) 0.5) |
| CuS-92Sun-newS.tdb | 1338.03 | FCC_A1 (x(S) 1.900e-4) + ION#2 (x(S) 0.01791) + ION (x(S) 0.32938) |
| CuS-92Sun-newS.tdb | 1314 | FCC_A1 (x(S) 1.600e-4) + ION (x(S) 0.32982) + CU2S_GAMMA (x(S) 0.33323) |
| CuS-92Sun-newS.tdb | 771.29 | CU2S_GAMMA (x(S) 0.3646) + CUS_B18 (x(S) 0.5) + LIQUID (x(S) 0.99984) |
| CuS-92Sun-newS.tdb | 710.93 | FCC_A1 (x(S) 0) + CU2S_BETA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.33341) |
| CuS-92Sun-newS.tdb | 384.34 | CUS_B18 (x(S) 0.5) + ORTHORHOMBIC_A16 (x(S) 1) + LIQUID (x(S) 1) |
| CuS-92Sun-newS.tdb | 375.97 | FCC_A1 (x(S) 0) + CU2S_ALPHA (x(S) 0.33333) + CU2S_BETA (x(S) 0.33333) |
| CuS-92Sun-newS.tdb | 375.97 | CU2S_BETA (x(S) 0.33333) + CU2S_ALPHA (x(S) 0.33333) + CU2S_GAMMA (x(S) 0.34555) |
| CuS-92Sun-newS.tdb | 371.95 | CU2S_ALPHA (x(S) 0.33333) + CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.34634) |
| CuS-92Sun-newS.tdb | 325.41 | CU31S16 (x(S) 0.3413) + CU2S_GAMMA (x(S) 0.35752) + CUS_B18 (x(S) 0.5) |
| CuS-92Sun-newS.tdb | 311.97 | CU31S16 (x(S) 0.3413) + CU7S4 (x(S) 0.36364) + CUS_B18 (x(S) 0.5) |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/CU/CU-S.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/CU/CU-S.json) · [CALPHAD hull CuS-92Sun-LB](https://data.orchid-project.org/hulls/calphad-sgte/CU/CU-S--CuS-92Sun-LB.json) · [CALPHAD hull CuS-92Sun-newS](https://data.orchid-project.org/hulls/calphad-sgte/CU/CU-S--CuS-92Sun-newS.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the Cu–S system (19)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 1409.15 | L2 = L1 + Dg | L2: S 0.3314; L1: S 0.022; Dg: S 0.333 | model | [1] Lee 2007 | Table 2, p. 4, row 2; `ORC-HHRTLBTKJT` |  |
| 1378.15 | L2 = L1 + Dg |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 24; `ORC-C67KLK2474` |  |
| 1342.15 | L1 = (Cu) + Dg | L1: S 0.0141; (Cu): S 2.000e-4; Dg: S 0.3331 | model | [1] Lee 2007 | Table 2, p. 4, row 4; `ORC-UXM22W6UCI` |  |
| 1340.15 | L1 = (Cu) + Dg |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 25; `ORC-LTHDBEMR4P` |  |
| 1087.15 | L2 = Dg + L3 | L2: S 0.4012; Dg: S 0.3642; L3: S 0.9986 | model | [1] Lee 2007 | Table 2, p. 4, row 17; `ORC-TBMITMWNG4` |  |
| 1086.15 | L2 = Dg + L3 |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 32; `ORC-JZNHRCNIWM` |  |
| 781.15 | Dg + L3 = Cv | Dg: S 0.3689; L3: S 0.9999 | model | [1] Lee 2007 | Table 2, p. 4, row 19; `ORC-L3CDFNG3RE` |  |
| 780.15 | Dg + L3 = Cv |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 33; `ORC-SA2LLP662L` |  |
| 388.15 | L + Cv = (S) |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 34; `ORC-2JY36N7T6U` |  |
| 388.15 | L + Cv = (S) |  | model | [1] Lee 2007 | Table 2, p. 4, row 20; `ORC-VVY3MCVHGH` |  |
| 379.15 | (Cu) + βCh = αCh |  | model | [1] Lee 2007 | Table 2, p. 4, row 8; `ORC-2LE5LDIH3R` |  |
| 377.15 | (Cu) + βCh = αCh |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 27; `ORC-3RJMFXQQDC` |  |
| 367.15 | βCh – Dg Dj | αCh: S 0.3333; Dg: S 0.3529; Dj: S 0.3413 | model | [1] Lee 2007 | Table 2, p. 4, row 10; `ORC-FES57T4DZ5` |  |
| 366.15 | βCh + Dg = Dj |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 28; `ORC-MA6L4K2P45` |  |
| 363.15 | βCh = αCh + Dj |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 29; `ORC-CWNPLURKAH` |  |
| 350.15 | Dg + Cv = An | Dg: S 0.3591 | model | [1] Lee 2007 | Table 2, p. 4, row 23; `ORC-VHD74AWCEW` |  |
| 348.15 | Dg + Cv = An |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 35; `ORC-TU6ZBM7OXW` |  |
| 345.15 | Dg + Dj = An |  | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 30; `ORC-UE2QIJ6NZZ` |  |
| 343.15 | Dg + Dj = An | Dg: S 0.3561; Dj: S 0.3413 | model | [1] Lee 2007 | Table 2, p. 4, row 13; `ORC-MR4537T6FY` |  |

## Other properties

### Phase transition (4)

Table: Phase transition, Cu–S system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 708.15 K | 708.15 | (Cu) + Dg = βCh | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 26; `ORC-7JWHZ322OK` |  |
| Phase transition | 708.15 K | 708.15 | (Cu) + Dg = βCh; _Dg: S 0.3334_ | model | [1] Lee 2007 | Table 2, p. 4, row 5; `ORC-ANFBPR2V5I` |  |
| Phase transition | 1403.15 K | 1403.15 | L = Dg | experimental | [1] Lee 2007; _cites Chakrabarti 1994_ | Table 2, p. 4, row 31; `ORC-IJ5G5R4AVO` |  |
| Phase transition | 1413.15 K | 1413.15 | L = Dg; _L: S 0.3355_ | model | [1] Lee 2007 | Table 2, p. 4, row 15; `ORC-VFHGQMTEFF` |  |

## Sources

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

1. Byeong-Joo Lee, Bo Sundman, Sung Il Kim, Kwang-Geun Chin, Thermodynamic Calculations on the Stability of Cu2S in Low Carbon Steels, ISIJ Int. 47, 163-171 (2007). [doi:10.2355/isijinternational.47.163](https://doi.org/10.2355/isijinternational.47.163)

## 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/).