# C–V system

> C–V system: 40 accepted literature values (invariant reaction 23, phase transition 12, phase equilibrium 4, crystal structure 1) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/C-V.html · Markdown: https://data.orchid-project.org/systems/C-V.md

40 accepted literature values from 2 paper(s) (experimental 22, model 15, unspecified 3); 0 calculated phase diagram(s). 4 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/C-V.json) · [CSV](https://data.orchid-project.org/systems/C-V.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#C-V) · [phases (10)](https://data.orchid-project.org/phases/pages/C-V.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/C-V.html) · [Markdown](https://data.orchid-project.org/systems/C-V.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 22 |
| model | 15 |
| unspecified | 3 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 23 |
| phase transition | 12 |
| phase equilibrium | 4 |
| crystal structure | 1 |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/C/C-V.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/C/C-V.json) · [CALPHAD hull VC-06Hu](https://data.orchid-project.org/hulls/calphad-sgte/C/C-V--VC-06Hu.json) · [CALPHAD hull VC-91Hua-LB](https://data.orchid-project.org/hulls/calphad-sgte/C/C-V--VC-91Hua-LB.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the C–V system (23)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 3073 | congruent melting: VCx \<-> liquid | VCx: C 0.475 | experimental | [1] Hu 2006; _cites Tretyachenko 1966_ | Table 2, p. 3, row 19; `ORC-DSODOQKV6N` |  |
| 2931 | congruent melting: VCx \<-> liquid | VCx: C 0.433 | model | [1] Hu 2006 | Table 2, p. 3, row 20; `ORC-N43KFHLUUG` |  |
| 2923 | Liquid \<-> VCx + graphite | Liquid: C 0.46 | experimental | [1] Hu 2006; _cites Storms 1962_ [doi](https://doi.org/10.1021/j100814a007) | Table 2, p. 3, row 21; `ORC-625YCSY677` |  |
| 2921 | congruent melting: VCx \<-> liquid | VCx: C 0.43 | experimental | [1] Hu 2006; _cites Storms 1962_ [doi](https://doi.org/10.1021/j100814a007) | Table 2, p. 3, row 18; `ORC-JVQBTMHRFK` |  |
| 2898 | Liquid \<-> VCx + graphite | Liquid: C 0.46; VCx: C 0.495 | experimental | [1] Hu 2006; _cites Rudy 1968_ | Table 2, p. 3, row 22; `ORC-WUIHSQXC3C` |  |
| 2879 | Liquid \<-> VCx + graphite | Liquid: C 0.452; VCx: C 0.495 | model | [1] Hu 2006 | Table 2, p. 3, row 23; `ORC-TALU6B3HNX` |  |
| 2466 | Liquid + VCx \<-> V2C | Liquid: C 0.258; VCx: C 0.371; V2C: C 0.325 | model | [1] Hu 2006 | Table 2, p. 3, row 17; `ORC-D22OTMJCVZ` |  |
| 2460 | Liquid + VCx \<-> V2C | Liquid: C 0.28; VCx: C 0.37; V2C: C 0.35 | experimental | [1] Hu 2006; _cites Rudy 1968_ | Table 2, p. 3, row 15; `ORC-KV7623FA3J` |  |
| 2438 | Liquid + VCx \<-> V2C | Liquid: C 0.28; VCx: C 0.37; V2C: C 0.333 | experimental | [1] Hu 2006; _cites Tretyachenko 1966_ | Table 2, p. 3, row 16; `ORC-CSJBGOQULA` |  |
| 2438 | Liquid + VCx \<-> V2C | VCx: C 0.375; V2C: C 0.36 | experimental | [1] Hu 2006; _cites Storms 1962_ [doi](https://doi.org/10.1021/j100814a007) | Table 2, p. 3, row 14; `ORC-OHQLAIFMNX` |  |
| 2150 | V2C + VCx \<-> V4C3-x | V2C: C 0.35; V4C3-x: C 0.379 | experimental | [1] Hu 2006; _cites Wiesenberger 1998_ [doi](https://doi.org/10.1016/s1359-6454%2897%2900204-8) | Table 2, p. 3, row 1; `ORC-KFUK2GXGYI` |  |
| 2149 | V2C + VCx \<-> V4C3-x | V2C: C 0.333333, V 0.666667; V4C3-x: C 0.379 | model | [1] Hu 2006 | Table 2, p. 3, row 2; `ORC-JMJQ5DNNNZ` |  |
| 1923 | Liquid \<-> V2C + bcc-(V) | Liquid: C 0.055; V2C: C 0.27; bcc-(V): C 0.15 | experimental | [1] Hu 2006; _cites Rudy 1968_ | Table 2, p. 3, row 11; `ORC-7R2LV5UTBG` |  |
| 1923 | Liquid \<-> V2C + bcc-(V) | V2C: C 0.3; bcc-(V): C 0.14 | experimental | [1] Hu 2006; _cites Tretyachenko 1966_ | Table 2, p. 3, row 12; `ORC-C37ADWUCXO` |  |
| 1922 | Liquid \<-> V2C + bcc-(V) | Liquid: C 0.0378; V2C: C 0.293; bcc-(V): C 0.133 | model | [1] Hu 2006 | Table 2, p. 3, row 13; `ORC-BLMHZGQX4O` |  |
| 1903 | Liquid \<-> V2C + bcc-(V) | Liquid: C 0.087; V2C: C 0.25 | experimental | [1] Hu 2006; _cites Storms 1962_ [doi](https://doi.org/10.1021/j100814a007) | Table 2, p. 3, row 10; `ORC-J4ZVQ7MCFQ` |  |
| 1540 | V4C3-x \<-> V2C + VCx | V4C3-x: C 0.379; V2C: C 0.35; VCx: C 0.419 | experimental | [1] Hu 2006; _cites Wiesenberger 1998_ [doi](https://doi.org/10.1016/s1359-6454%2897%2900204-8) | Table 2, p. 3, row 3; `ORC-UAVCLGVT44` |  |
| 1535 | V4C3-x \<-> V2C + VCx | V4C3-x: C 0.379; V2C: C 0.333; VCx: C 0.421 | model | [1] Hu 2006 | Table 2, p. 3, row 4; `ORC-RKTZ6Q7DLN` |  |
| 1397 | polymorphic: V8C7 \<-> VCx | V8C7: C 0.467 | experimental | [1] Hu 2006; _cites Shacklette 1973_ [doi](https://doi.org/10.1103/physrevb.7.5041) | Table 2, p. 3, row 6; `ORC-L5XCWV2JTO` |  |
| 1385 | polymorphic: V8C7 \<-> VCx | V8C7: C 0.467 | unspecified | [1] Hu 2006; _cites Emmons 1983_ [doi](https://doi.org/10.1007/bf00547575) | Table 2, p. 3, row 5; `ORC-DBWI6JC7LS` |  |
| 1383 | polymorphic: V8C7 \<-> VCx | V8C7: C 0.467 | model | [1] Hu 2006 | Table 2, p. 3, row 7; `ORC-ZUFOATHZL7` |  |
| 1331 | VCx \<-> V6C5 + V8C7 | VCx: C 0.46; V6C5: C 0.454545, V 0.545455; V8C7: C 0.467 | unspecified | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 2, p. 3, row 8; `ORC-ZSH7WJLDVH` |  |
| 1329 | VCx \<-> V6C5 + V8C7 | VCx: C 0.459; V6C5: C 0.451; V8C7: C 0.467 | model | [1] Hu 2006 | Table 2, p. 3, row 9; `ORC-TPXDACUIAN` |  |

## Other properties

### Phase transition (12)

Table: Phase transition, C–V system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 1329 K | 1329 | eutectic: VCx \<-> V6C5 + V8C7; _alloy: V 0.545455_ | model | [1] Hu 2006 | Table 1, p. 2, row 28; `ORC-LYRKN2DYRR` |  |
| Phase transition | 1331 K | 1331 | eutectic: VCx \<-> V6C5 + V8C7; _alloy: V 0.545455_ | experimental | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 27; `ORC-SQWF3STINR` |  |
| Phase transition | 1366 K | 1366 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | model | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 22; `ORC-MSDXTGWB2T` |  |
| Phase transition | 1380 K | 1380 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | model | [1] Hu 2006 | Table 1, p. 2, row 24; `ORC-BWWQED3C3X` |  |
| Phase transition | 1428 K | 1428 | order-disorder: VCx + V6C5 \<-> V6C5; _alloy: V 0.545455_ | model | [1] Hu 2006 | Table 1, p. 2, row 26; `ORC-57MCQMHTPX` |  |
| Phase transition | 1430 K | 1430 | order-disorder: VCx + V6C5 \<-> V6C5; _alloy: V 0.545455_ | experimental | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 25; `ORC-K6PEENY6EW` |  |
| Phase transition | 1440 K | 1440 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | experimental | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 19; `ORC-WTN7RBVLIC` |  |
| Phase transition | 1448 K | 1448 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | model | [1] Hu 2006 | Table 1, p. 2, row 23; `ORC-KUMD3KPFMS` |  |
| Phase transition | 1450 K | 1450 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | model | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 21; `ORC-N6ZYND34EK` |  |
| Phase transition | 1457 K | 1457 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | experimental | [1] Hu 2006; _cites Emmons 1983_ [doi](https://doi.org/10.1007/bf00547575) | Table 1, p. 2, row 20; `ORC-WIR35Y567N` |  |
| Phase transition | 1473 K | 1473 | order-disorder: VCx \<-> V6C5 + VCx; _alloy: V 0.545455_ | experimental | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 18; `ORC-QRBUAQX6GT` |  |
| Phase transition | 2183 K | 2183 | bcc | experimental | [1] Hu 2006 | p. 4; `ORC-SSUJ3O3L5Z` | “However, in order to avoid a kink in CP due to the change in the description of ◦ Gbcc V at the melting point (2183 K), it is decided to replace ◦ Gbcc V in Eqs. (7) and (8) with a quantity ◦ Ghyp , which is identical to ◦ Gbcc except that the expression for V V φ 790 to 2183 K is used extensively up to 4000 K \[2\].” |

### Phase equilibrium (4)

Table: Phase equilibrium, C–V system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase composition |  | 1358 | congruent melting: V8C7 \<-> VCx; _liquid: V 0.533333; V8C7: V 0.533333_ | experimental | [1] Hu 2006; _cites Lipatnikov 1999_ [doi](https://doi.org/10.1088/0953-8984/11/1/014) | Table 1, p. 2, row 29; `ORC-QH4PO4BLNZ` |  |
| Phase composition |  | 1383 | congruent melting: V8C7 \<-> VCx; _liquid: V 0.533333; V8C7: V 0.533333_ | model | [1] Hu 2006 | Table 1, p. 2, row 32; `ORC-WFAISWLNA7` |  |
| Phase composition |  | 1385 | congruent melting: V8C7 \<-> VCx; _liquid: V 0.533333; V8C7: V 0.533333_ | experimental | [1] Hu 2006; _cites Emmons 1983_ [doi](https://doi.org/10.1007/bf00547575) | Table 1, p. 2, row 30; `ORC-U2VQYLVLNE` |  |
| Phase composition |  | 1397 | congruent melting: V8C7 \<-> VCx; _liquid: V 0.533333; V8C7: V 0.533333_ | experimental | [1] Hu 2006; _cites Shacklette 1973_ [doi](https://doi.org/10.1103/physrevb.7.5041) | Table 1, p. 2, row 31; `ORC-NI52U2AIXX` |  |

### Crystal structure (1)

Table: Crystal structure, C–V system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| volume; _printed: Ω_ | 9.058 unknown |  | η-VC; _alloy: V 0.5_ | unspecified | [2] Bratberg 2002 | Table 3, p. 7, row 2; `ORC-4JHEU2Z4BR.eaaafd` |  |

## Sources

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

1. Jincheng Hu, Changrong Li, Fuming Wang, Weijing Zhang, Thermodynamic re-assessment of the V–C system, Journal of Alloys and Compounds 421, 120-127 (2006). [doi:10.1016/j.jallcom.2005.11.033](https://doi.org/10.1016/j.jallcom.2005.11.033)
2. Johan Bratberg, Karin Frisk, A thermodynamic analysis of the Mo-V and Mo-V-C system, Calphad 26, 459-476 (2002). [doi:10.1016/s0364-5916(02)00057-3](https://doi.org/10.1016/s0364-5916%2802%2900057-3)

## 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-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); 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.

```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_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/).