# C–Pr phases > C–Pr system: 8 phases (tier A 6, tier C 1, liquid 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/C-PR.html · Markdown: https://data.orchid-project.org/phases/pages/C-PR.md 8 phases (tier A 6, tier C 1, liquid 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=C-PR) · [full JSON](https://data.orchid-project.org/phases/systems/C-PR.json) · [C–Pr system page](https://data.orchid-project.org/systems/C-PR.html) · [Markdown](https://data.orchid-project.org/phases/pages/C-PR.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md) Table: Phases of the C–Pr system (8) | Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models | |---|---|---|---|---:|---:| | [DIAMOND_A4](#phase-c-pr-a4-diamond); _phase:c-pr:a4-diamond_ | C (diamond) · A4 · cF8 · Fd-3m (227) | tier A: standard phase name | not stable in 1 calculated diagram(s) | 0 | 1 | | [GRAPHITE_A9](#phase-c-pr-a9-graphite); _phase:c-pr:a9-graphite_ | C (graphite) · A9 · hP4 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–4000 K, x(C) 1–1 | 0 | 1 | | [BCC_A2](#phase-c-pr-bcc-a2); _phase:c-pr:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 948.99–2429 K, x(C) 0–0.0773 | 0 | 1 | | [DHCP](#phase-c-pr-dhcp-a3); _phase:c-pr:dhcp-a3_ | alpha-La · A3' · hP4 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1153 K, x(C) 0–0.04431 | 0 | 1 | | [LIQUID](#phase-c-pr-liquid); _phase:c-pr:liquid_ | liquid | liquid | stable in 1 of 1 calculated diagram(s): 1072.12–4000 K, x(C) 0–0.86142 | 0 | 1 | | [PR2C3_D5C](#phase-c-pr-pr2c3-d5c); _phase:c-pr:pr2c3-d5c_ | Pu2C3 · D5_c · cI40 · I-43d (220) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1821.15 K, x(C) 0.54404–0.6 | 0 | 1 | | [PRC2_BETA](#phase-c-pr-prc2-beta); _phase:c-pr:prc2-beta_ | CaC2 · cF36 · Fm-3m (225) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 1427.43–2589.18 K, x(C) 0.65795–0.66612 | 0 | 1 | | [PRC2_C11A](#phase-c-pr-prc2-c11a); _phase:c-pr:prc2-c11a_ | CaC2 · C11_a · tI6 · I4/mmm (139) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1413.6 K, x(C) 0.66667–0.66667 | 0 | 1 | ## DIAMOND_A4 (C–Pr) - Id: `phase:c-pr:a4-diamond`; status `assigned` - Structure: C (diamond) · A4 · cF8 · Fd-3m (227); type `st:a4-c-diamond-cf8`; tier A: standard phase name; confidence high - Stoichiometry: C 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:c-pr:a4-diamond) Names (2): _corpus: _corpus:phase:c-pr:a4-diamond _tdb: _tdb:PrC-11Pen.tdb:DIAMOND_A4 ### TDB models of DIAMOND_A4 (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): DIAMOND_A4, type code %, sha256 `7207a325d93d7b08…` ~~~~text 46: PHASE DIAMOND_A4 % 1 1 ! 47: CONST DIAMOND_A4 : C : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## GRAPHITE_A9 (C–Pr) - Id: `phase:c-pr:a9-graphite`; status `assigned` - Structure: C (graphite) · A9 · hP4 · P6_3/mmc (194); type `st:a9-c-graphite-hp4`; tier A: standard phase name; confidence high - Stoichiometry: C 1.0000 - Stability: stable in 1 of 1 calculated diagram(s): 300–4000 K, x(C) 1–1 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:a9-graphite) Names (2): _corpus: _corpus:phase:c-pr:a9-graphite _tdb: _tdb:PrC-11Pen.tdb:GRAPHITE_A9 ### TDB models of GRAPHITE_A9 (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): GRAPHITE_A9, type code %, sha256 `7207a325d93d7b08…` ~~~~text 51: PHASE GRAPHITE_A9 % 1 1 ! 52: CONST GRAPHITE_A9 : C : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## BCC_A2 (C–Pr) - Id: `phase:c-pr:bcc-a2`; status `assigned` - Structure: W · A2 · cI2 · Im-3m (229); type `st:a2-w-ci2`; tier A: standard phase name; confidence high - Stability: stable in 1 of 1 calculated diagram(s): 948.99–2429 K, x(C) 0–0.0773 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:bcc-a2) Names (2): _corpus: _corpus:phase:c-pr:bcc-a2 _tdb: _tdb:PrC-11Pen.tdb:BCC_A2 ### TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): BCC_A2, type code %B, sha256 `7207a325d93d7b08…` ~~~~text 36: PHASE BCC_A2 %B 2 1 3 ! 37: CONST BCC_A2 : PR : C VA% : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## DHCP (C–Pr) - Id: `phase:c-pr:dhcp-a3`; status `assigned` - Structure: alpha-La · A3' · hP4 · P6_3/mmc (194); type `st:a3-alpha-la-hp4`; tier A: standard phase name; confidence high - Stability: stable in 1 of 1 calculated diagram(s): 300–1153 K, x(C) 0–0.04431 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:dhcp-a3) Names (2): _corpus: _corpus:phase:c-pr:dhcp-a3 _tdb: _tdb:PrC-11Pen.tdb:DHCP ### TDB models of DHCP (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): DHCP, type code %, sha256 `7207a325d93d7b08…` ~~~~text 41: PHASE DHCP % 2 1 1 ! 42: CONST DHCP : PR : C VA% : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## LIQUID (C–Pr) - Id: `phase:c-pr:liquid`; status `assigned` - Structure: liquid; type `st:liquid`; liquid; confidence high - Stability: stable in 1 of 1 calculated diagram(s): 1072.12–4000 K, x(C) 0–0.86142 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:liquid) Names (2): _corpus: _corpus:phase:c-pr:liquid _tdb: _tdb:PrC-11Pen.tdb:LIQUID ### TDB models of LIQUID (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): LIQUID, type code %, sha256 `7207a325d93d7b08…` ~~~~text 31: PHASE LIQUID:L % 1 1 ! 32: CONST LIQUID:L : C PR : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## PR2C3_D5C (C–Pr) - Id: `phase:c-pr:pr2c3-d5c`; status `assigned` - Structure: Pu2C3 · D5_c · cI40 · I-43d (220); type `st:d5-c-pu2c3-ci40`; tier A: standard phase name; confidence high - Stability: stable in 1 of 1 calculated diagram(s): 300–1821.15 K, x(C) 0.54404–0.6 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:pr2c3-d5c) Names (2): _corpus: _corpus:phase:c-pr:pr2c3-d5c _tdb: _tdb:PrC-11Pen.tdb:PR2C3_D5C ### TDB models of PR2C3_D5C (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): PR2C3_D5C, type code %, sha256 `7207a325d93d7b08…` ~~~~text 56: PHASE PR2C3_D5C % 2 2 3 ! 57: CONST PR2C3_D5C : PR : C% VA : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## PRC2_BETA (C–Pr) - Id: `phase:c-pr:prc2-beta`; status `assigned` - Structure: CaC2 · cF36 · Fm-3m (225); type `st:cac2-cf36`; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated - Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) [doi:10.1016/j.calphad.2025.102833](https://doi.org/10.1016/j.calphad.2025.102833) - Caveat: not certain from the name or DFT alone (no_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system - Stability: stable in 1 of 1 calculated diagram(s): 1427.43–2589.18 K, x(C) 0.65795–0.66612 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:prc2-beta) Names (2): _corpus: _corpus:phase:c-pr:prc2-beta _tdb: _tdb:PrC-11Pen.tdb:PRC2_BETA ### TDB models of PRC2_BETA (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): PRC2_BETA, type code %, sha256 `7207a325d93d7b08…` ~~~~text 66: PHASE PRC2_BETA % 2 1 2 ! 67: CONST PRC2_BETA : PR : C% VA : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _assessment that models this phase_ ## PRC2_C11A (C–Pr) - Id: `phase:c-pr:prc2-c11a`; status `assigned` - Structure: CaC2 · C11_a · tI6 · I4/mmm (139); type `st:c11-a-cac2-ti6`; tier A: standard phase name; confidence high - Stoichiometry: C 0.6667, Pr 0.3333 - Stability: stable in 1 of 1 calculated diagram(s): 300–1413.6 K, x(C) 0.66667–0.66667 - Literature: 0 values (0 accepted) from 0 papers - Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:c-pr:prc2-c11a) Names (2): _corpus: _corpus:phase:c-pr:prc2-c11a _tdb: _tdb:PrC-11Pen.tdb:PRC2_C11A ### TDB models of PRC2_C11A (1): PHASE and CONSTITUENT statements as written [PrC-11Pen.tdb](https://orchid-project.org/data/databases/sgte-binary/PrC-11Pen.tdb): PRC2_C11A, type code %, sha256 `7207a325d93d7b08…` ~~~~text 61: PHASE PRC2_C11A % 2 1 2 ! 62: CONST PRC2_C11A : PR : C : ! ~~~~ Example references (1 of 1; assessments first): - [doi:10.1016/j.calphad.2011.09.002](https://doi.org/10.1016/j.calphad.2011.09.002) Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). _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).