Os–Si phases

8 phases (tier A 4, tier B 1, tier C 2, liquid 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 · Os–Si system page · Markdown · field reference

Phases of the Os–Si system (8)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
DIAMOND_A4 phase:os-si:a4-diamond	C (diamond) · A4 · cF8 · Fd-3m (227)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–3999.76 K, x(Si) 1–1	4	1
MSI_B20 phase:os-si:b20-msi	FeSi · B20 · cP8 · P2_13 (198)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–2013.01 K, x(Si) 0.5–0.5	4	1
BCC_A2 phase:os-si:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
FCC_A1 phase:os-si:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
HCP_A3 phase:os-si:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–3331.55 K, x(Si) 0–0	2	1
LIQUID phase:os-si:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1616.01–4000 K, x(Si) 0–1	13	1
OS2SI3 phase:os-si:os2si3	Ge3Ru2 · oP40 · Pbcn (60)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–2103.93 K, x(Si) 0.6–0.6	6	1
OSSI2 phase:os-si:ossi2	FeSi2-h · oC48 · Cmce (64)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1922.11 K, x(Si) 0.66667–0.66667	6	1

DIAMOND_A4 (Os–Si)

Id: phase:os-si: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: Si 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–3999.76 K, x(Si) 1–1
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:os-si:a4-diamond, corpus:phase:os-si:diamond-a4
paper: paper:10.1016/s0925-8388(01)00931-8:Diamond
tdb: tdb:OsSi-01Liu-LB.tdb:DIAMOND_A4

TDB models of DIAMOND_A4 (1): PHASE and CONSTITUENT statements as written

OsSi-01Liu-LB.tdb: DIAMOND_A4, type code %, sha256 661081800c525b84…

45: PHASE DIAMOND_A4 % 1 1 !
46: CONST DIAMOND_A4 : SI : !

Example references (4 of 4; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-0248(83)90424-4 K. Mason, G. Müller-Vogt, Osmium disilicide: Preparation, crystal growth, and physical properties of a new semiconducting compound, Journal of Crystal Growth 63, 34-38 (1983).
cited as the source of values for this phase
doi:10.1016/0022-5088(62)90055-3 Lies N Finnie, Structures and compositions of the silicides of ruthenium, osmium, rhodium and iridium, Journal of the Less Common Metals 4, 24-34 (1962).
cited as the source of values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase

MSI_B20 (Os–Si)

Id: phase:os-si:b20-msi; status assigned
Structure: FeSi · B20 · cP8 · P2_13 (198); type st:b20-fesi-cp8; 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:MSI); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Os 0.5000, Si 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–2013.01 K, x(Si) 0.5–0.5
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:os-si:b20-msi, corpus:phase:os-si:msi-b20
paper: paper:10.1016/s0925-8388(01)00931-8:OsSi
tdb: tdb:OsSi-01Liu-LB.tdb:MSI_B20

TDB models of MSI_B20 (1): PHASE and CONSTITUENT statements as written

OsSi-01Liu-LB.tdb: MSI_B20, type code %, sha256 661081800c525b84…

50: PHASE MSI_B20 % 2 1 1 !
51: CONST MSI_B20 : OS : SI : !

Example references (2 of 2; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase

BCC_A2 (Os–Si)

Id: phase:os-si: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:os-si:bcc-a2
tdb: tdb:OsSi-01Liu-LB.tdb:BCC_A2

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

OsSi-01Liu-LB.tdb: BCC_A2, type code %B, sha256 661081800c525b84…

35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : OS SI : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase

FCC_A1 (Os–Si)

Id: phase:os-si: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 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:os-si:fcc-a1
tdb: tdb:OsSi-01Liu-LB.tdb:FCC_A1

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

OsSi-01Liu-LB.tdb: FCC_A1, type code %A, sha256 661081800c525b84…

30: PHASE FCC_A1 %A 2 1 1 !
31: CONST FCC_A1 : OS SI : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase

HCP_A3 (Os–Si)

Id: phase:os-si: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): 300–3331.55 K, x(Si) 0–0
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:os-si:hcp-a3
paper: paper:10.1016/s0925-8388(01)00931-8:(Os)
tdb: tdb:OsSi-01Liu-LB.tdb:HCP_A3

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

OsSi-01Liu-LB.tdb: HCP_A3, type code %, sha256 661081800c525b84…

40: PHASE HCP_A3 % 2 1 0.5 !
41: CONST HCP_A3 : OS% SI : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase

LIQUID (Os–Si)

Id: phase:os-si:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1616.01–4000 K, x(Si) 0–1
Literature: 13 values (13 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:os-si:liquid
paper: paper:10.1016/s0925-8388(01)00931-8:liquid
tdb: tdb:OsSi-01Liu-LB.tdb:LIQUID

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

OsSi-01Liu-LB.tdb: LIQUID, type code %, sha256 661081800c525b84…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : OS SI : !

Example references (4 of 4; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase
doi:10.1016/0022-0248(83)90424-4 K. Mason, G. Müller-Vogt, Osmium disilicide: Preparation, crystal growth, and physical properties of a new semiconducting compound, Journal of Crystal Growth 63, 34-38 (1983).
cited as the source of values for this phase
doi:10.1016/0022-5088(62)90055-3 Lies N Finnie, Structures and compositions of the silicides of ruthenium, osmium, rhodium and iridium, Journal of the Less Common Metals 4, 24-34 (1962).
cited as the source of values for this phase

OS2SI3 (Os–Si)

Id: phase:os-si:os2si3; status assigned
Structure: Ge3Ru2 · oP40 · Pbcn (60); type st:ge3ru2-op40; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: Os 0.4000, Si 0.6000
Stability: stable in 1 of 1 calculated diagram(s): 300–2103.93 K, x(Si) 0.6–0.6
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:os-si:os2si3
mp: mp:mp-aaaaayou
oqmd: oqmd:oqmd-83466
paper: paper:10.1016/s0925-8388(01)00931-8:Os2Si3
tdb: tdb:OsSi-01Liu-LB.tdb:OS2SI3

TDB models of OS2SI3 (1): PHASE and CONSTITUENT statements as written

OsSi-01Liu-LB.tdb: OS2SI3, type code %, sha256 661081800c525b84…

55: PHASE OS2SI3 % 2 2 3 !
56: CONST OS2SI3 : OS : SI : !

Example references (2 of 2; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase

OSSI2 (Os–Si)

Id: phase:os-si:ossi2; status assigned
Structure: FeSi2-h · oC48 · Cmce (64); type st:fesi2-h-oc48; 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 (dft_space_group_64_matches_2_structure_types, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Os 0.3333, Si 0.6667
Stability: stable in 1 of 1 calculated diagram(s): 300–1922.11 K, x(Si) 0.66667–0.66667
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:os-si:ossi2
paper: paper:10.1016/s0925-8388(01)00931-8:OsSi2
tdb: tdb:OsSi-01Liu-LB.tdb:OSSI2

TDB models of OSSI2 (1): PHASE and CONSTITUENT statements as written

OsSi-01Liu-LB.tdb: OSSI2, type code %, sha256 661081800c525b84…

60: PHASE OSSI2 % 2 1 2 !
61: CONST OSSI2 : OS : SI : !

Example references (4 of 4; assessments first):

doi:10.1016/S0925-8388(01)00931-8 Y.Q. Liu, G. Shao, K.P. Homewood, J. Alloys Compd., 320, 72-79(2001).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(88)90148-8 L. Schellenberg, H.F. Braun, J. Muller, The osmium-silicon phase diagram, Journal of the Less Common Metals 144, 341-350 (1988).
cited as the source of values for this phase
doi:10.1016/0022-0248(83)90424-4 K. Mason, G. Müller-Vogt, Osmium disilicide: Preparation, crystal growth, and physical properties of a new semiconducting compound, Journal of Crystal Growth 63, 34-38 (1983).
cited as the source of values for this phase
doi:10.1016/0022-5088(62)90055-3 Lies N Finnie, Structures and compositions of the silicides of ruthenium, osmium, rhodium and iridium, Journal of the Less Common Metals 4, 24-34 (1962).
cited as the source of values for 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}
}