# Cr–Nb–Ta system

> Cr–Nb–Ta system: 73 accepted literature values (crystal structure 52, formation 21) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/CR-NB-TA.html · Markdown: https://data.orchid-project.org/systems/CR-NB-TA.md

73 accepted literature values from 1 paper(s) (experimental 11, model 8, DFT 53, unspecified 1); 0 calculated phase diagram(s).

Data: [JSON](https://data.orchid-project.org/literature/systems/CR-NB-TA.json) · [CSV](https://data.orchid-project.org/systems/CR-NB-TA.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#CR-NB-TA) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/CR-NB-TA.html) · [Markdown](https://data.orchid-project.org/systems/CR-NB-TA.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 11 |
| model | 8 |
| DFT | 53 |
| unspecified | 1 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| formation | 21 |
| crystal structure | 52 |

## 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, Cr–Nb–Ta system (21)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| C14 |  | -32.453 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 4; `ORC-5OECTYJJRX` |  |
| C14 |  | -31.113 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 3; `ORC-X6OU7EMCTI` |  |
| C14 |  | -26.02 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 2; `ORC-KQ6TIKCKX2` |  |
| C14 |  | -24.86 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 1; `ORC-NVKSWQXP5S` |  |
| C14 |  | -10.25 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 8; `ORC-H6LURFPPQT` |  |
| C14 |  | -8.928 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 7; `ORC-JAOCIVIOXU` |  |
| C14 |  | -1.81 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 6; `ORC-2AMHRLAK4H` |  |
| C14 |  | -0.65 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 5; `ORC-DYNOR5SMUM` |  |
| C14 |  | 27.8 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009; _cites Sluiter 2006_ [doi](https://doi.org/10.1016/j.calphad.2006.09.002) | Table 3, p. 3, row 2; `ORC-XPFVHPS323` |  |
| C14 |  | 28.63 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 3, p. 3, row 1; `ORC-ES7WBWG5LT` |  |
| C15 |  | -33.13 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 12; `ORC-IMF2VHCCK4` |  |
| C15 |  | -31.646 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 11; `ORC-J5KII3K3PC` |  |
| C15 |  | -26.903 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 10; `ORC-4BULNUDTKK` |  |
| C15 |  | -25.649 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 9; `ORC-5DJS2FBL5I` |  |
| C15 |  | -11.29 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 16; `ORC-NJLLH663ZH` |  |
| C15 |  | -9.824 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 15; `ORC-LYVRUB3WRI` |  |
| C15 |  | -3.31 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 14; `ORC-QVZWW3JK5Y` |  |
| C15 |  | -2.055 kJ/mol (basis unstated) | 2000 | model |  |  | [1] Pavlů 2009 | Table 9, p. 6, row 13; `ORC-EXPKZ2NPD5` |  |
| C15 |  | 26.4 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009; _cites Sluiter 2006_ [doi](https://doi.org/10.1016/j.calphad.2006.09.002) | Table 3, p. 3, row 8; `ORC-SYCF5BGIYI` |  |
| C15 |  | 27.29 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 3, p. 3, row 7; `ORC-H5NIFIADAU` |  |
| C36 |  | 27.75 kJ/mol (basis unstated) | 0 | DFT |  |  | [1] Pavlů 2009 | Table 3, p. 3, row 13; `ORC-JKJTHW7WHH` |  |

## Other properties

### Crystal structure (52)

Table: Crystal structure, Cr–Nb–Ta system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Lattice a | 2.85 Å |  | Antiferromagnetic BCC Cr; _alloy: Nb 0, Ta 0_ | unspecified | [1] Pavlů 2009 | Table 1, p. 3, row 1; `ORC-UTWTP4KQL6` |  |
| Lattice a | 4.64 Å | 0 | C14; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 1; `ORC-2RPRH3B3OI.9c8cbc` |  |
| Lattice a | 5.32 Å | 0 | C14; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 9; `ORC-ASILF2UOA3.2bcd00` |  |
| Lattice a | 4.88 Å | 0 | C14; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 4; `ORC-MR3KF2X62T.0da16e` |  |
| Lattice a | 5.38 Å | 0 | C14; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 6; `ORC-OCXTRNCN52.c9ef42` |  |
| Lattice a | 4.87 Å | 0 | C14; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 7; `ORC-WV4SIYDMTL.979d8f` |  |
| Lattice a | 6.93 Å | 0 | C15; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 13; `ORC-3OMG2JHHN5.95b8f0` |  |
| Lattice a | 7.5 Å | 0 | C15; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 15; `ORC-G74V4GZDHX.df71a2` |  |
| Lattice a | 7.48 Å | 0 | C15; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 18; `ORC-GRY62GNPXS.46e110` |  |
| Lattice a | 6.58 Å | 0 | C15; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 10; `ORC-VG3QF5YZSI.4e15f2` |  |
| Lattice a | 6.91 Å | 0 | C15; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 16; `ORC-WFZDXPQBJG.295969` |  |
| Lattice a | 4.9 Å | 0 | C36; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 22; `ORC-332G7ECRUJ.13282c` |  |
| Lattice a | 5.3 Å | 0 | C36; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 25; `ORC-5UBTNPDB2B.d96bfe` |  |
| Lattice a | 4.88 Å | 0 | C36; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 24; `ORC-L6CIZ6TI63.55a437` |  |
| Lattice a | 4.65 Å | 0 | C36; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 19; `ORC-XAC3DESWQX.d6b7ea` |  |
| Lattice a | 5.32 Å | 0 | C36; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 23; `ORC-ZKCLUOV7Z2.790009` |  |
| Lattice a | 2.88 Å | 298.15 | Antiferromagnetic BCC Cr; _alloy: Nb 0, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 1, p. 3, row 2; `ORC-WYJ3XUTTZS` |  |
| Lattice a | 4.93 Å | 298.15 | C14; _alloy: Nb 0.333333, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 5; `ORC-TQIMUKTXH7.7c469e` |  |
| Lattice a | 4.93 Å | 298.15 | C14; _alloy: Nb 0, Ta 0.333333_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 8; `ORC-ZWMYLUMJVP.b0c0a1` |  |
| Lattice a | 6.97 Å | 298.15 | C15; _alloy: Nb 0.333333, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 14; `ORC-4NS7PVOV7U.a7713b` |  |
| Lattice a | 7 Å | 298.15 | C15; _alloy: Nb 0, Ta 0.333333_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 17; `ORC-HXQZJN2UP6.b5f0b2` |  |
| Lattice c | 7.66 Å | 0 | C14; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 1; `ORC-2RPRH3B3OI.01c7e7` |  |
| Lattice c | 8.5 Å | 0 | C14; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 9; `ORC-ASILF2UOA3.b2d66d` |  |
| Lattice c | 8.06 Å | 0 | C14; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 4; `ORC-MR3KF2X62T.19283f` |  |
| Lattice c | 8.36 Å | 0 | C14; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 6; `ORC-OCXTRNCN52.33251a` |  |
| Lattice c | 8.03 Å | 0 | C14; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 7; `ORC-WV4SIYDMTL.91c526` |  |
| Lattice c | 16.02 Å | 0 | C36; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 22; `ORC-332G7ECRUJ.20a194` |  |
| Lattice c | 17.18 Å | 0 | C36; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 25; `ORC-5UBTNPDB2B.cb46d4` |  |
| Lattice c | 15.98 Å | 0 | C36; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 24; `ORC-L6CIZ6TI63.536e2f` |  |
| Lattice c | 15.23 Å | 0 | C36; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 19; `ORC-XAC3DESWQX.fb8d25` |  |
| Lattice c | 17.15 Å | 0 | C36; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 23; `ORC-ZKCLUOV7Z2.d3d7b2` |  |
| Lattice c | 8.12 Å | 298.15 | C14; _alloy: Nb 0.333333, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 5; `ORC-TQIMUKTXH7.f95a3c` |  |
| Lattice c | 8.06 Å | 298.15 | C14; _alloy: Nb 0, Ta 0.333333_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 8; `ORC-ZWMYLUMJVP.0e3316` |  |
| lattice 2v atom | 2.777 10^7 pm^3 | 0 | C36; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 22; `ORC-332G7ECRUJ.0576a5` |  |
| lattice 2v atom | 3.486 10^7 pm^3 | 0 | C36; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 25; `ORC-5UBTNPDB2B.9667a8` |  |
| lattice 2v atom | 2.747 10^7 pm^3 | 0 | C36; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 24; `ORC-L6CIZ6TI63.ec9388` |  |
| lattice 2v atom | 2.378 10^7 pm^3 | 0 | C36; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 19; `ORC-XAC3DESWQX.214de4` |  |
| lattice 2v atom | 3.508 10^7 pm^3 | 0 | C36; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 23; `ORC-ZKCLUOV7Z2.97b8f6` |  |
| lattice v atom | 1.191 10^7 pm^3 | 0 | C14; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 1; `ORC-2RPRH3B3OI.e3ff11` |  |
| lattice v atom | 1.74 10^7 pm^3 | 0 | C14; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 9; `ORC-ASILF2UOA3.f62ff4` |  |
| lattice v atom | 1.39 10^7 pm^3 | 0 | C14; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 4; `ORC-MR3KF2X62T.686bd1` |  |
| lattice v atom | 1.474 10^7 pm^3 | 0 | C14; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 6; `ORC-OCXTRNCN52.c18cea` |  |
| lattice v atom | 1.375 10^7 pm^3 | 0 | C14; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 7; `ORC-WV4SIYDMTL.4c2c9c` |  |
| lattice v atom | 1.388 10^7 pm^3 | 0 | C15; _alloy: Nb 0.333333, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 13; `ORC-3OMG2JHHN5.eea371` |  |
| lattice v atom | 1.755 10^7 pm^3 | 0 | C15; _alloy: Nb 0.666667, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 15; `ORC-G74V4GZDHX.2225d7` |  |
| lattice v atom | 1.744 10^7 pm^3 | 0 | C15; _alloy: Nb 0, Ta 0.666667_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 18; `ORC-GRY62GNPXS.e48947` |  |
| lattice v atom | 1.187 10^7 pm^3 | 0 | C15; _alloy: Nb 0, Ta 0_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 10; `ORC-VG3QF5YZSI.d3c67d` |  |
| lattice v atom | 1.372 10^7 pm^3 | 0 | C15; _alloy: Nb 0, Ta 0.333333_ | DFT | [1] Pavlů 2009 | Table 2, p. 3, row 16; `ORC-WFZDXPQBJG.e2fb08` |  |
| lattice v atom | 1.424 10^7 pm^3 | 298.15 | C14; _alloy: Nb 0.333333, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 5; `ORC-TQIMUKTXH7.7e00dd` |  |
| lattice v atom | 1.411 10^7 pm^3 | 298.15 | C14; _alloy: Nb 0, Ta 0.333333_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 8; `ORC-ZWMYLUMJVP.94a6d0` |  |
| lattice v atom | 1.413 10^7 pm^3 | 298.15 | C15; _alloy: Nb 0.333333, Ta 0_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 14; `ORC-4NS7PVOV7U.77c983` |  |
| lattice v atom | 1.427 10^7 pm^3 | 298.15 | C15; _alloy: Nb 0, Ta 0.333333_ | experimental | [1] Pavlů 2009; _cites Villars 1991_ | Table 2, p. 3, row 17; `ORC-HXQZJN2UP6.b08fe4` |  |

## Sources

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

1. J. Pavlů, J. Vřešt’ál, M. Šob, Re-modeling of Laves phases in the Cr–Nb and Cr–Ta systems using first-principles results, Calphad 33, 179-186 (2009). [doi:10.1016/j.calphad.2008.04.006](https://doi.org/10.1016/j.calphad.2008.04.006)

## 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 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_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/).