# Co–Te phases

> Co–Te system: 8 phases (tier A 6, liquid 1, gas 1); 7 stable in a calculated diagram in the ORCHID phase registry, with names, structure type when the stored evidence supports an assignment under the stated tier rules, calculated stability, verbatim TDB PHASE/CONSTITUENT statements and example references.

HTML: https://data.orchid-project.org/phases/pages/CO-TE.html · Markdown: https://data.orchid-project.org/phases/pages/CO-TE.md

8 phases (tier A 6, liquid 1, gas 1); 7 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model).

Data: [interactive registry](https://orchid-project.org/phases/?q=CO-TE) · [full JSON](https://data.orchid-project.org/phases/systems/CO-TE.json) · [Co–Te system page](https://data.orchid-project.org/systems/CO-TE.html) · [Markdown](https://data.orchid-project.org/phases/pages/CO-TE.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the Co–Te system (8)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [HEXAGONAL_A8](#phase-co-te-a8-hexagonal); _phase:co-te:a8-hexagonal_ | gamma-Se · A8 · hP3 · P3_121 (152) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–722.61 K, x(Te) 1–1 | 0 | 1 |
| [BCC_A2](#phase-co-te-bcc-a2); _phase:co-te:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | not stable in 1 calculated diagram(s) | 0 | 1 |
| [COTE_B81](#phase-co-te-cote-b81); _phase:co-te:cote-b81_ | NiAs · B8_1 · hP4 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1286.07 K, x(Te) 0.55016–0.64138 | 0 | 1 |
| [COTE2_C18](#phase-co-te-cote2-c18); _phase:co-te:cote2-c18_ | alpha-FeS2 · C18 · oP6 · Pnnm (58) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1037.11 K, x(Te) 0.66667–0.70419 | 0 | 1 |
| [FCC_A1](#phase-co-te-fcc-a1); _phase:co-te:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 694.99–1774.11 K, x(Te) 0–0 | 0 | 1 |
| [GAS](#phase-co-te-gas); _phase:co-te:gas_ | gas | gas | stable in 1 of 1 calculated diagram(s): 1267.25–2500 K, x(Te) 0.98949–1 | 0 | 1 |
| [HCP_A3](#phase-co-te-hcp-a3); _phase:co-te:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1250 K, x(Te) 0–0 | 0 | 1 |
| [LIQUID](#phase-co-te-liquid); _phase:co-te:liquid_ | liquid | liquid | stable in 1 of 1 calculated diagram(s): 722.61–2500 K, x(Te) 0–1 | 0 | 1 |

## HEXAGONAL_A8 (Co–Te)

- Id: `phase:co-te:a8-hexagonal`; status `assigned`
- Structure: gamma-Se · A8 · hP3 · P3_121 (152); type `st:a8-gamma-se-hp3`; tier A: standard phase name; confidence high
- Stoichiometry: Te 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 300–722.61 K, x(Te) 1–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:a8-hexagonal)

Names (2): _corpus: _corpus:phase:co-te:a8-hexagonal  
_tdb: _tdb:CoTe-20Yua.tdb:HEXAGONAL_A8  


### TDB models of HEXAGONAL_A8 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): HEXAGONAL_A8, type code %, sha256 `023eef9733a28a9a…`

~~~~text
53: PHASE HEXAGONAL_A8 % 1 1 !
54: CONST HEXAGONAL_A8 : TE : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## BCC_A2 (Co–Te)

- Id: `phase:co-te:bcc-a2`; status `assigned`
- Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high
- Stoichiometry: Co 1.0000
- Stability: not stable in 1 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:bcc-a2)

Names (2): _corpus: _corpus:phase:co-te:bcc-a2  
_tdb: _tdb:CoTe-20Yua.tdb:BCC_A2  


### TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): BCC_A2, type code %B, sha256 `023eef9733a28a9a…`

~~~~text
41: PHASE BCC_A2 %B 2 1 3 !
42: CONST BCC_A2 : CO : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## COTE_B81 (Co–Te)

- Id: `phase:co-te:cote-b81`; status `assigned`
- Structure: NiAs · B8_1 · hP4 · P6_3/mmc (194); type `st:b8-1-nias-hp4`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 300–1286.07 K, x(Te) 0.55016–0.64138
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:cote-b81)

Names (2): _corpus: _corpus:phase:co-te:cote-b81  
_tdb: _tdb:CoTe-20Yua.tdb:COTE_B81  


### TDB models of COTE_B81 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): COTE_B81, type code %, sha256 `023eef9733a28a9a…`

~~~~text
58: PHASE COTE_B81 % 3 1 1 1 !
59: CONST COTE_B81 : CO VA : CO VA : TE : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## COTE2_C18 (Co–Te)

- Id: `phase:co-te:cote2-c18`; status `assigned`
- Structure: alpha-FeS2 · C18 · oP6 · Pnnm (58); type `st:c18-alpha-fes2-op6`; tier A: standard phase name; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 300–1037.11 K, x(Te) 0.66667–0.70419
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:cote2-c18)

Names (2): _corpus: _corpus:phase:co-te:cote2-c18  
_tdb: _tdb:CoTe-20Yua.tdb:COTE2_C18  


### TDB models of COTE2_C18 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): COTE2_C18, type code %, sha256 `023eef9733a28a9a…`

~~~~text
63: PHASE COTE2_C18 % 2 1 2 !
64: CONST COTE2_C18 : CO% TE : TE : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## FCC_A1 (Co–Te)

- Id: `phase:co-te:fcc-a1`; status `assigned`
- Structure: Cu · A1 · cF4 · Fm-3m (225); type `st:a1-cu-cf4`; tier A: standard phase name; confidence high
- Stoichiometry: Co 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 694.99–1774.11 K, x(Te) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:fcc-a1)

Names (2): _corpus: _corpus:phase:co-te:fcc-a1  
_tdb: _tdb:CoTe-20Yua.tdb:FCC_A1  


### TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): FCC_A1, type code %A, sha256 `023eef9733a28a9a…`

~~~~text
36: PHASE FCC_A1 %A 2 1 1 !
37: CONST FCC_A1 : CO : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## GAS (Co–Te)

- Id: `phase:co-te:gas`; status `assigned`
- Structure: gas; type `st:gas`; gas; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 1267.25–2500 K, x(Te) 0.98949–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:gas)

Names (2): _corpus: _corpus:phase:co-te:gas  
_tdb: _tdb:CoTe-20Yua.tdb:GAS  


### TDB models of GAS (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): GAS, type code %, sha256 `023eef9733a28a9a…`

~~~~text
66: PHASE GAS:G % 1 1 !
67: CONST GAS:G : CO CO2 COTE TE TE2 TE3 TE4 TE5 TE6 TE7 : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## HCP_A3 (Co–Te)

- Id: `phase:co-te:hcp-a3`; status `assigned`
- Structure: Mg · A3 · hP2 · P6_3/mmc (194); type `st:a3-mg-hp2`; tier A: standard phase name; confidence high
- Stoichiometry: Co 1.0000
- Stability: stable in 1 of 1 calculated diagram(s): 300–1250 K, x(Te) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:hcp-a3)

Names (2): _corpus: _corpus:phase:co-te:hcp-a3  
_tdb: _tdb:CoTe-20Yua.tdb:HCP_A3  


### TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): HCP_A3, type code %A, sha256 `023eef9733a28a9a…`

~~~~text
46: PHASE HCP_A3 %A 2 1 0.5 !
47: CONST HCP_A3 : CO : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## LIQUID (Co–Te)

- Id: `phase:co-te:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 722.61–2500 K, x(Te) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:co-te:liquid)

Names (2): _corpus: _corpus:phase:co-te:liquid  
_tdb: _tdb:CoTe-20Yua.tdb:LIQUID  


### TDB models of LIQUID (1): PHASE and CONSTITUENT statements as written

[CoTe-20Yua.tdb](https://orchid-project.org/data/databases/sgte-binary/CoTe-20Yua.tdb): LIQUID, type code %, sha256 `023eef9733a28a9a…`

~~~~text
31: PHASE LIQUID:L % 1 1 !
32: CONST LIQUID:L : CO TE : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.calphad.2020.101743](https://doi.org/10.1016/j.calphad.2020.101743) H. Yuan, J. Wang, B. Hu, R. Zhao, Y. Du, S.-Y. Zhang, Calphad, 68, 101743(2020).  
_assessment that models this phase_

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735970
- 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 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); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work).

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_phase_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  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 the ORCHID phase registry and the sources named on the page (TDB assessments, Hallstedt 2025, Materials Project, OQMD). TDB statements are quoted as written; parameter expressions are not reproduced. Field reference: [SCHEMA.md](https://data.orchid-project.org/phases/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt).