B–Co phases

8 phases (tier A 4, tier C 2, liquid 1, needs_review 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 · full JSON · B–Co system page · Markdown · field reference

Phases of the B–Co system (8)
Phase	Structure	Basis	Stability (calculated)	TDB models
BETA_RHOMBO_B phase:b-co:b-beta-rhombo		needs_review	stable in 1 of 1 calculated diagram(s): 300–2353.52 K, x(B) 1–1	1
MB_B27 phase:b-co:b27-mb	FeB · B27 · oP8 · Pnma (62)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1735.07 K, x(B) 0.5–0.5	1
BCC_A2 phase:b-co:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 1 calculated diagram(s)	1
M2B_C16 phase:b-co:c16-m2b	Al2Cu · C16 · tI12 · I4/mcm (140)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1548.65 K, x(B) 0.33333–0.33333	1
CO3B_D011 phase:b-co:co3b-d011	Fe3C · D0_11 · oP16 · Pnma (62)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 1115.91–1431.15 K, x(B) 0.25–0.25	1
FCC_A1 phase:b-co:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 694.99–2741.34 K, x(B) 0–0.00222	1
HCP_A3 phase:b-co:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1759.99 K, x(B) 0–0	1
LIQUID phase:b-co:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1406.34–4000 K, x(B) 0–1	1

BETA_RHOMBO_B (B–Co)

Id: phase:b-co:b-beta-rhombo; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:RHOMBO; no_structure_token
Candidate (sgte_mmc2): beta-B · hR105 · R-3m (166) — Hallstedt 2025 mmc2 row for BETA_RHOMBO_B: beta-B
Candidate (tdb_comment): beta-B · hR105 · R-3m — CoB-02Du-LB.tdb: 'Prototype beta-B (hR105, R-3m)'
Stoichiometry: B 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–2353.52 K, x(B) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:b-beta-rhombo
tdb: tdb:CoB-02Du-LB.tdb:BETA_RHOMBO_B

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

CoB-02Du-LB.tdb: BETA_RHOMBO_B, type code %, sha256 936043c413bb18ac…

49: PHASE BETA_RHOMBO_B % 1 1 !
50: CONST BETA_RHOMBO_B : B : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

MB_B27 (B–Co)

Id: phase:b-co:b27-mb; status assigned
Structure: FeB · B27 · oP8 · Pnma (62); type st:b27-feb-op8; 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
Caveat: not certain from the name or DFT alone (name_has_descriptive_tokens:MB, no_structure_token, structure_token_is_also_a_formula); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: B 0.5000, Co 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–1735.07 K, x(B) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:b27-mb
tdb: tdb:CoB-02Du-LB.tdb:MB_B27

TDB models of MB_B27 (1): PHASE and CONSTITUENT statements as written

CoB-02Du-LB.tdb: MB_B27, type code %, sha256 936043c413bb18ac…

64: PHASE MB_B27 % 2 1 1 !
65: CONST MB_B27 : CO : B : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

BCC_A2 (B–Co)

Id: phase:b-co:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:bcc-a2
tdb: tdb:CoB-02Du-LB.tdb:BCC_A2

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

CoB-02Du-LB.tdb: BCC_A2, type code %B, sha256 936043c413bb18ac…

39: PHASE BCC_A2 %B 2 1 3 !
40: CONST BCC_A2 : B CO% : VA : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

M2B_C16 (B–Co)

Id: phase:b-co:c16-m2b; status assigned
Structure: Al2Cu · C16 · tI12 · I4/mcm (140); type st:c16-al2cu-ti12; 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
Caveat: not certain from the name or DFT alone (unrecognised_name_tokens:M2B); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: B 0.3333, Co 0.6667
Stability: stable in 1 of 1 calculated diagram(s): 300–1548.65 K, x(B) 0.33333–0.33333
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:c16-m2b
tdb: tdb:CoB-02Du-LB.tdb:M2B_C16

TDB models of M2B_C16 (1): PHASE and CONSTITUENT statements as written

CoB-02Du-LB.tdb: M2B_C16, type code %, sha256 936043c413bb18ac…

59: PHASE M2B_C16 % 2 2 1 !
60: CONST M2B_C16 : CO : B : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

CO3B_D011 (B–Co)

Id: phase:b-co:co3b-d011; status assigned
Structure: Fe3C · D0_11 · oP16 · Pnma (62); type st:d0-11-fe3c-op16; tier A: standard phase name; confidence high
Stoichiometry: B 0.2500, Co 0.7500
Stability: stable in 1 of 1 calculated diagram(s): 1115.91–1431.15 K, x(B) 0.25–0.25
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:co3b-d011
tdb: tdb:CoB-02Du-LB.tdb:CO3B_D011

TDB models of CO3B_D011 (1): PHASE and CONSTITUENT statements as written

CoB-02Du-LB.tdb: CO3B_D011, type code %, sha256 936043c413bb18ac…

54: PHASE CO3B_D011 % 2 3 1 !
55: CONST CO3B_D011 : CO : B : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

FCC_A1 (B–Co)

Id: phase:b-co:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 694.99–2741.34 K, x(B) 0–0.00222
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:fcc-a1
tdb: tdb:CoB-02Du-LB.tdb:FCC_A1

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

CoB-02Du-LB.tdb: FCC_A1, type code %A, sha256 936043c413bb18ac…

34: PHASE FCC_A1 %A 2 1 1 !
35: CONST FCC_A1 : B CO% : VA : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

HCP_A3 (B–Co)

Id: phase:b-co:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–1759.99 K, x(B) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:hcp-a3
tdb: tdb:CoB-02Du-LB.tdb:HCP_A3

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

CoB-02Du-LB.tdb: HCP_A3, type code %A, sha256 936043c413bb18ac…

44: PHASE HCP_A3 %A 2 1 0.5 !
45: CONST HCP_A3 : B CO% : VA : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
assessment that models this phase

LIQUID (B–Co)

Id: phase:b-co:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1406.34–4000 K, x(B) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:b-co:liquid
tdb: tdb:CoB-02Du-LB.tdb:LIQUID

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

CoB-02Du-LB.tdb: LIQUID, type code %, sha256 936043c413bb18ac…

29: PHASE LIQUID:L % 1 1 !
30: CONST LIQUID:L : B CO : !

Example references (1 of 1; assessments first):

doi:10.3139/146.021157 Y. Du, J.C. Schuster, Y.A. Chang, Z. Jin, B. Huang, Z. Metallkd., 93 ,1157-63(2002).
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). doi: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). doi: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.

@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}
}