As–Ni phases

9 phases (tier A 5, tier B 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 · Markdown · field reference

Phases of the As–Ni system (9)
Phase	Structure	Basis	Stability (calculated)	TDB models
RHOMBOHEDRAL_A7 phase:as-ni:a7-rhombohedral	alpha-As · A7 · hR2 · R-3m (166)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1090 K, x(As) 1–1	1
BCC_A2 phase:as-ni:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 1 calculated diagram(s)	1
FCC_A1 phase:as-ni:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2213.24 K, x(As) 0–0.07094	1
HCP_A3 phase:as-ni:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 1 calculated diagram(s)	1
LIQUID phase:as-ni:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 973.57–2500 K, x(As) 0–1	1
NI11AS8 phase:as-ni:ni11as8	Ni11As8 · tP76 · P4_12_12 (92)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–1158.29 K, x(As) 0.42105–0.42105	1
NI5AS2 phase:as-ni:ni5as2	Pd5Sb2 · hP42 · P6_3cm (185)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–1286.11 K, x(As) 0.28571–0.28571	1
NIAS_B81 phase:as-ni:nias-b81	NiAs · B8_1 · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1266.54 K, x(As) 0.5–0.5	1
NIAS2 phase:as-ni:nias2		needs_review	stable in 1 of 1 calculated diagram(s): 300–1127.54 K, x(As) 0.66667–0.66667	1

RHOMBOHEDRAL_A7 (As–Ni)

Id: phase:as-ni:a7-rhombohedral; status assigned
Structure: alpha-As · A7 · hR2 · R-3m (166); type st:a7-alpha-as-hr2; tier A: standard phase name; confidence high
Stoichiometry: As 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–1090 K, x(As) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:a7-rhombohedral
tdb: tdb:NiAs-01Uhl.tdb:RHOMBOHEDRAL_A7

TDB models of RHOMBOHEDRAL_A7 (1): PHASE and CONSTITUENT statements as written

NiAs-01Uhl.tdb: RHOMBOHEDRAL_A7, type code %, sha256 968fca0a518bfee0…

40: PHASE RHOMBOHEDRAL_A7 % 1 1 !
41: CONST RHOMBOHEDRAL_A7 : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

BCC_A2 (As–Ni)

Id: phase:as-ni: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:as-ni:bcc-a2
tdb: tdb:NiAs-01Uhl.tdb:BCC_A2

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

NiAs-01Uhl.tdb: BCC_A2, type code %B, sha256 968fca0a518bfee0…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : AS NI : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

FCC_A1 (As–Ni)

Id: phase:as-ni: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): 300–2213.24 K, x(As) 0–0.07094
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:fcc-a1
tdb: tdb:NiAs-01Uhl.tdb:FCC_A1

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

NiAs-01Uhl.tdb: FCC_A1, type code %A, sha256 968fca0a518bfee0…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : AS NI% : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

HCP_A3 (As–Ni)

Id: phase:as-ni: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: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:hcp-a3
tdb: tdb:NiAs-01Uhl.tdb:HCP_A3

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

NiAs-01Uhl.tdb: HCP_A3, type code %A, sha256 968fca0a518bfee0…

35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : AS NI : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

LIQUID (As–Ni)

Id: phase:as-ni:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 973.57–2500 K, x(As) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:liquid
tdb: tdb:NiAs-01Uhl.tdb:LIQUID

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

NiAs-01Uhl.tdb: LIQUID, type code %, sha256 968fca0a518bfee0…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : AS NI : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

NI11AS8 (As–Ni)

Id: phase:as-ni:ni11as8; status assigned
Structure: Ni11As8 · tP76 · P4_12_12 (92); type st:ni11as8-tp76; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: As 0.4211, Ni 0.5789
Stability: stable in 1 of 1 calculated diagram(s): 300–1158.29 K, x(As) 0.42105–0.42105
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:as-ni:ni11as8
mp: mp:mp-aaaabptr
oqmd: oqmd:oqmd-43653
tdb: tdb:NiAs-01Uhl.tdb:NI11AS8

TDB models of NI11AS8 (1): PHASE and CONSTITUENT statements as written

NiAs-01Uhl.tdb: NI11AS8, type code %, sha256 968fca0a518bfee0…

50: PHASE NI11AS8 % 2 11 8 !
51: CONST NI11AS8 : NI : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

NI5AS2 (As–Ni)

Id: phase:as-ni:ni5as2; status assigned
Structure: Pd5Sb2 · hP42 · P6_3cm (185); type st:pd5sb2-hp42; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: As 0.2857, Ni 0.7143
Stability: stable in 1 of 1 calculated diagram(s): 300–1286.11 K, x(As) 0.28571–0.28571
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:as-ni:ni5as2
mp: mp:mp-aaaaabkf
oqmd: oqmd:oqmd-2965
tdb: tdb:NiAs-01Uhl.tdb:NI5AS2

TDB models of NI5AS2 (1): PHASE and CONSTITUENT statements as written

NiAs-01Uhl.tdb: NI5AS2, type code %, sha256 968fca0a518bfee0…

45: PHASE NI5AS2 % 2 5 2 !
46: CONST NI5AS2 : NI : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

NIAS_B81 (As–Ni)

Id: phase:as-ni:nias-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
Stoichiometry: As 0.5000, Ni 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–1266.54 K, x(As) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:nias-b81
tdb: tdb:NiAs-01Uhl.tdb:NIAS_B81

TDB models of NIAS_B81 (1): PHASE and CONSTITUENT statements as written

NiAs-01Uhl.tdb: NIAS_B81, type code %, sha256 968fca0a518bfee0…

55: PHASE NIAS_B81 % 2 1 1 !
56: CONST NIAS_B81 : NI : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
assessment that models this phase

NIAS2 (As–Ni)

Id: phase:as-ni:nias2; status needs_review
No structure assigned. Why: dft_space_group_61_matches_3_structure_types; no_structure_token; sgte_mmc2_row_disagrees_with_dft; sgte_mmc2_rows_disagree
Candidate (dft_mp): Pbca (61) — on-hull MP NiAs2 at x(NI)=0.3333
Candidate (dft_oqmd): Pbca (61) — on-hull OQMD As2 Ni1 at x(NI)=0.3333
Candidate (dft_space_group_and_stoichiometry): AuSn2 · oP24 · Pbca (61) — space group 61 and stoichiometry match
Candidate (dft_space_group_and_stoichiometry): TiO2 · C21 · oP24 · Pbca (61) — space group 61 and stoichiometry match
Candidate (dft_space_group_and_stoichiometry): NiAs2 · oP24 · Pbca (61) — space group 61 and stoichiometry match
Candidate (sgte_mmc2): alpha-FeS2 · C18 · oP6 · Pnnm (58) — Hallstedt 2025 mmc2 row for NIAS2: NiAs2 (rammelsbergite, see also NiAs2)
Candidate (sgte_mmc2): NiAs2 · oP24 · Pbca (61) — Hallstedt 2025 mmc2 row for NIAS2: NiAs2 (pararammelsbergite, see also FeAs2)
Candidate (tdb_comment): FeS2 · oP6 · Pnnm, C18 — NiAs-01Uhl.tdb: 'Prototype FeS2 (oP6, Pnnm, C18), rammelsbergite, high T ?'
Stoichiometry: As 0.6667, Ni 0.3333
Stability: stable in 1 of 1 calculated diagram(s): 300–1127.54 K, x(As) 0.66667–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:as-ni:nias2
tdb: tdb:NiAs-01Uhl.tdb:NIAS2

TDB models of NIAS2 (1): PHASE and CONSTITUENT statements as written

NiAs-01Uhl.tdb: NIAS2, type code %, sha256 968fca0a518bfee0…

61: PHASE NIAS2 % 2 1 2 !
62: CONST NIAS2 : NI : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/S0364-5916(01)00034-7 S. Uhland, H. Lechtman, L. Kaufman, Calphad, 25, 109-24(2001).
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}
}