Al–As phases

7 phases (tier A 5, liquid 1, gas 1); 5 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 · Al–As system page · Markdown · field reference

Phases of the Al–As system (7)
Phase	Structure	Basis	Stability (calculated)	TDB models
RHOMBOHEDRAL_A7 phase:al-as:a7-rhombohedral	alpha-As · A7 · hR2 · R-3m (166)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–888.4 K, x(As) 1–1	1
ZINCBLENDE_B3 phase:al-as:b3-zincblende	ZnS (sphalerite) · B3 · cF8 · F-43m (216)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2052.43 K, x(As) 0.5–0.5	1
BCC_A2 phase:al-as:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 1 calculated diagram(s)	1
FCC_A1 phase:al-as:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–935.47 K, x(As) 0–0	1
GAS phase:al-as:gas	gas	gas	stable in 1 of 1 calculated diagram(s): 888.4–2500 K, x(As) 0.96159–1	1
HCP_A3 phase:al-as:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 1 calculated diagram(s)	1
LIQUID phase:al-as:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 933.33–2500 K, x(As) 0–0.45908	1

RHOMBOHEDRAL_A7 (Al–As)

Id: phase:al-as: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): 300–888.4 K, x(As) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-as:a7-rhombohedral
tdb: tdb:AlAs-84Ans-LB.tdb:RHOMBOHEDRAL_A7

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

AlAs-84Ans-LB.tdb: RHOMBOHEDRAL_A7, type code %, sha256 17a1a9155346aacd…

47: PHASE RHOMBOHEDRAL_A7 % 1 1 !
48: CONST RHOMBOHEDRAL_A7 : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

ZINCBLENDE_B3 (Al–As)

Id: phase:al-as:b3-zincblende; status assigned
Structure: ZnS (sphalerite) · B3 · cF8 · F-43m (216); type st:b3-zns-sphalerite-cf8; tier A: standard phase name; confidence high
Caveat: DFT agrees: on-hull mp-aaaaadfo and oqmd-12376, space group 216
Stoichiometry: Al 0.5000, As 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–2052.43 K, x(As) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:al-as:b3-zincblende
mp: mp:mp-aaaaadfo
oqmd: oqmd:oqmd-12376
tdb: tdb:AlAs-84Ans-LB.tdb:ZINCBLENDE_B3

TDB models of ZINCBLENDE_B3 (1): PHASE and CONSTITUENT statements as written

AlAs-84Ans-LB.tdb: ZINCBLENDE_B3, type code %, sha256 17a1a9155346aacd…

52: PHASE ZINCBLENDE_B3 % 2 1 1 !
53: CONST ZINCBLENDE_B3 : AL : AS : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

BCC_A2 (Al–As)

Id: phase:al-as: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:al-as:bcc-a2
tdb: tdb:AlAs-84Ans-LB.tdb:BCC_A2

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

AlAs-84Ans-LB.tdb: BCC_A2, type code %B, sha256 17a1a9155346aacd…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : AL AS : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

FCC_A1 (Al–As)

Id: phase:al-as: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): 300–935.47 K, x(As) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-as:fcc-a1
tdb: tdb:AlAs-84Ans-LB.tdb:FCC_A1

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

AlAs-84Ans-LB.tdb: FCC_A1, type code %A, sha256 17a1a9155346aacd…

32: PHASE FCC_A1 %A 2 1 1 !
33: CONST FCC_A1 : AL% AS : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

GAS (Al–As)

Id: phase:al-as:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 888.4–2500 K, x(As) 0.96159–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-as:gas
tdb: tdb:AlAs-84Ans-LB.tdb:GAS

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

AlAs-84Ans-LB.tdb: GAS, type code %, sha256 17a1a9155346aacd…

55: PHASE GAS:G % 1 1 !
56: CONST GAS:G : AL AL2 ALAS AS AS2 AS4 : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

HCP_A3 (Al–As)

Id: phase:al-as: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:al-as:hcp-a3
tdb: tdb:AlAs-84Ans-LB.tdb:HCP_A3

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

AlAs-84Ans-LB.tdb: HCP_A3, type code %A, sha256 17a1a9155346aacd…

42: PHASE HCP_A3 %A 2 1 0.5 !
43: CONST HCP_A3 : AL AS : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
assessment that models this phase

LIQUID (Al–As)

Id: phase:al-as:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 933.33–2500 K, x(As) 0–0.45908
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:al-as:liquid
tdb: tdb:AlAs-84Ans-LB.tdb:LIQUID

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

AlAs-84Ans-LB.tdb: LIQUID, type code %, sha256 17a1a9155346aacd…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : AL AS : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(84)90035-X I. Ansara, D. Dutartre, Calphad, 8, 323-42(1984).
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}
}