C–Mg phases

9 phases (tier A 5, tier C 2, liquid 1, gas 1); 6 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 · Markdown · field reference

Phases of the C–Mg system (9)
Phase	Structure	Basis	Stability (calculated)	TDB models
DIAMOND_A4 phase:c-mg:a4-diamond	C (diamond) · A4 · cF8 · Fd-3m (227)	tier A: standard phase name	not stable in 3 calculated diagram(s)	3
GRAPHITE_A9 phase:c-mg:a9-graphite	C (graphite) · A9 · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 300–3999.5 K, x(C) 1–1	3
BCC_A2 phase:c-mg:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 3 calculated diagram(s)	3
FCC_A1 phase:c-mg:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 3 calculated diagram(s)	3
GAS phase:c-mg:gas	gas	gas	stable in 3 of 3 calculated diagram(s): 1367.53–4000 K, x(C) 0–1	3
HCP_A3 phase:c-mg:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 3 of 3 calculated diagram(s): 300–3999.54 K, x(C) 0–0.0001	3
LIQUID phase:c-mg:liquid	liquid	liquid	stable in 3 of 3 calculated diagram(s): 688.82–3999.54 K, x(C) 0–0.25128	3
MG2C3 phase:c-mg:mg2c3	Mg2C3 · oP10 · Pnnm (58)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 3 calculated diagram(s): 300–930.23 K, x(C) 0.6–0.6	3
MGC2 phase:c-mg:mgc2	MgC2 · tP6 · P4_2/mnm (136)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 3 calculated diagram(s): 300–869.96 K, x(C) 0.66667–0.66667	3

DIAMOND_A4 (C–Mg)

Id: phase:c-mg: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 3 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:a4-diamond
tdb: tdb:MgC-06Hal.tdb:DIAMOND_A4, tdb:MgC-10Hu.tdb:DIAMOND_A4, tdb:MgC-12Che.tdb:DIAMOND_A4

TDB models of DIAMOND_A4 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: DIAMOND_A4, type code %, sha256 cdafe04b706df3aa…

56: PHASE DIAMOND_A4 % 1 1 !
57: CONST DIAMOND_A4 : C : !

MgC-10Hu.tdb: DIAMOND_A4, type code %, sha256 2ed80eae8ee075a6…

52: PHASE DIAMOND_A4 % 1 1 !
53: CONST DIAMOND_A4 : C : !

MgC-12Che.tdb: DIAMOND_A4, type code %, sha256 662147a17bbe63f9…

52: PHASE DIAMOND_A4 % 1 1 !
53: CONST DIAMOND_A4 : C : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

GRAPHITE_A9 (C–Mg)

Id: phase:c-mg: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 3 of 3 calculated diagram(s): 300–3999.5 K, x(C) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:a9-graphite
tdb: tdb:MgC-06Hal.tdb:GRAPHITE_A9, tdb:MgC-10Hu.tdb:GRAPHITE_A9, tdb:MgC-12Che.tdb:GRAPHITE_A9

TDB models of GRAPHITE_A9 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: GRAPHITE_A9, type code %, sha256 cdafe04b706df3aa…

61: PHASE GRAPHITE_A9 % 1 1 !
62: CONST GRAPHITE_A9 : C : !

MgC-10Hu.tdb: GRAPHITE_A9, type code %, sha256 2ed80eae8ee075a6…

57: PHASE GRAPHITE_A9 % 1 1 !
58: CONST GRAPHITE_A9 : C : !

MgC-12Che.tdb: GRAPHITE_A9, type code %, sha256 662147a17bbe63f9…

57: PHASE GRAPHITE_A9 % 1 1 !
58: CONST GRAPHITE_A9 : C : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

BCC_A2 (C–Mg)

Id: phase:c-mg: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 3 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:bcc-a2
tdb: tdb:MgC-06Hal.tdb:BCC_A2, tdb:MgC-10Hu.tdb:BCC_A2, tdb:MgC-12Che.tdb:BCC_A2

TDB models of BCC_A2 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: BCC_A2, type code %B, sha256 cdafe04b706df3aa…

46: PHASE BCC_A2 %B 2 1 3 !
47: CONST BCC_A2 : MG : C VA% : !

MgC-10Hu.tdb: BCC_A2, type code %B, sha256 2ed80eae8ee075a6…

42: PHASE BCC_A2 %B 2 1 3 !
43: CONST BCC_A2 : MG : C VA% : !

MgC-12Che.tdb: BCC_A2, type code %B, sha256 662147a17bbe63f9…

42: PHASE BCC_A2 %B 2 1 3 !
43: CONST BCC_A2 : MG : C VA% : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

FCC_A1 (C–Mg)

Id: phase:c-mg:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stability: not stable in 3 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:fcc-a1
tdb: tdb:MgC-06Hal.tdb:FCC_A1, tdb:MgC-10Hu.tdb:FCC_A1, tdb:MgC-12Che.tdb:FCC_A1

TDB models of FCC_A1 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: FCC_A1, type code %A, sha256 cdafe04b706df3aa…

41: PHASE FCC_A1 %A 2 1 1 !
42: CONST FCC_A1 : MG : C VA% : !

MgC-10Hu.tdb: FCC_A1, type code %A, sha256 2ed80eae8ee075a6…

37: PHASE FCC_A1 %A 2 1 1 !
38: CONST FCC_A1 : MG : C VA% : !

MgC-12Che.tdb: FCC_A1, type code %A, sha256 662147a17bbe63f9…

37: PHASE FCC_A1 %A 2 1 1 !
38: CONST FCC_A1 : MG : C VA% : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

GAS (C–Mg)

Id: phase:c-mg:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 3 of 3 calculated diagram(s): 1367.53–4000 K, x(C) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:gas
tdb: tdb:MgC-06Hal.tdb:GAS, tdb:MgC-10Hu.tdb:GAS, tdb:MgC-12Che.tdb:GAS

TDB models of GAS (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: GAS, type code %, sha256 cdafe04b706df3aa…

74: PHASE GAS:G % 1 1 !
75: CONST GAS:G : C C2 C3 C4 C5 C60 MG MG2 : !

MgC-10Hu.tdb: GAS, type code %, sha256 2ed80eae8ee075a6…

70: PHASE GAS:G % 1 1 !
71: CONST GAS:G : C C2 C3 C4 C5 C60 MG MG2 : !

MgC-12Che.tdb: GAS, type code %, sha256 662147a17bbe63f9…

70: PHASE GAS:G % 1 1 !
71: CONST GAS:G : C C2 C3 C4 C5 C60 MG MG2 : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

HCP_A3 (C–Mg)

Id: phase:c-mg: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 3 of 3 calculated diagram(s): 300–3999.54 K, x(C) 0–0.0001
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:hcp-a3
tdb: tdb:MgC-06Hal.tdb:HCP_A3, tdb:MgC-10Hu.tdb:HCP_A3, tdb:MgC-12Che.tdb:HCP_A3

TDB models of HCP_A3 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: HCP_A3, type code %, sha256 cdafe04b706df3aa…

51: PHASE HCP_A3 % 2 1 0.5 !
52: CONST HCP_A3 : MG% : C VA% : !

MgC-10Hu.tdb: HCP_A3, type code %, sha256 2ed80eae8ee075a6…

47: PHASE HCP_A3 % 2 1 0.5 !
48: CONST HCP_A3 : MG% : C VA% : !

MgC-12Che.tdb: HCP_A3, type code %, sha256 662147a17bbe63f9…

47: PHASE HCP_A3 % 2 1 0.5 !
48: CONST HCP_A3 : MG% : C VA% : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

LIQUID (C–Mg)

Id: phase:c-mg:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 3 of 3 calculated diagram(s): 688.82–3999.54 K, x(C) 0–0.25128
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:liquid
tdb: tdb:MgC-06Hal.tdb:LIQUID, tdb:MgC-10Hu.tdb:LIQUID, tdb:MgC-12Che.tdb:LIQUID

TDB models of LIQUID (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: LIQUID, type code %, sha256 cdafe04b706df3aa…

36: PHASE LIQUID:L % 1 1 !
37: CONST LIQUID:L : C MG : !

MgC-10Hu.tdb: LIQUID, type code %, sha256 2ed80eae8ee075a6…

32: PHASE LIQUID:L % 1 1 !
33: CONST LIQUID:L : C MG : !

MgC-12Che.tdb: LIQUID, type code %, sha256 662147a17bbe63f9…

32: PHASE LIQUID:L % 1 1 !
33: CONST LIQUID:L : C MG : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

MG2C3 (C–Mg)

Id: phase:c-mg:mg2c3; status assigned
Structure: Mg2C3 · oP10 · Pnnm (58); type st:mg2c3-op10; 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 (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: C 0.6000, Mg 0.4000
Stability: stable in 1 of 3 calculated diagram(s): 300–930.23 K, x(C) 0.6–0.6
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:mg2c3
tdb: tdb:MgC-06Hal.tdb:MG2C3, tdb:MgC-10Hu.tdb:MG2C3, tdb:MgC-12Che.tdb:MG2C3

TDB models of MG2C3 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: MG2C3, type code %, sha256 cdafe04b706df3aa…

66: PHASE MG2C3 % 2 2 3 !
67: CONST MG2C3 : MG : C : !

MgC-10Hu.tdb: MG2C3, type code %, sha256 2ed80eae8ee075a6…

62: PHASE MG2C3 % 2 2 3 !
63: CONST MG2C3 : MG : C : !

MgC-12Che.tdb: MG2C3, type code %, sha256 662147a17bbe63f9…

62: PHASE MG2C3 % 2 2 3 !
63: CONST MG2C3 : MG : C : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
assessment that models this phase

MGC2 (C–Mg)

Id: phase:c-mg:mgc2; status assigned
Structure: MgC2 · tP6 · P4_2/mnm (136); type st:mgc2-tp6; 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 (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: C 0.6667, Mg 0.3333
Stability: stable in 1 of 3 calculated diagram(s): 300–869.96 K, x(C) 0.66667–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:c-mg:mgc2
tdb: tdb:MgC-06Hal.tdb:MGC2, tdb:MgC-10Hu.tdb:MGC2, tdb:MgC-12Che.tdb:MGC2

TDB models of MGC2 (3): PHASE and CONSTITUENT statements as written

MgC-06Hal.tdb: MGC2, type code %, sha256 cdafe04b706df3aa…

71: PHASE MGC2 % 2 1 2 !
72: CONST MGC2 : MG : C : !

MgC-10Hu.tdb: MGC2, type code %, sha256 2ed80eae8ee075a6…

67: PHASE MGC2 % 2 1 2 !
68: CONST MGC2 : MG : C : !

MgC-12Che.tdb: MGC2, type code %, sha256 662147a17bbe63f9…

67: PHASE MGC2 % 2 1 2 !
68: CONST MGC2 : MG : C : !

Example references (2 of 2; assessments first):

doi:10.2298/JMMB1001097H B. Hu, Y. Du, H. Xu, W. Sun, W.W. Zhang, D. Zhao, J. Mining Metall. B, 46, 97-103(2010).
assessment that models this phase
doi:10.3139/146.110787 H.-L. Chen, R. Schmid-Fetzer, Int. J. Mater. Res., 103, 1294-1301(2012).
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}
}