Si–W phases

7 phases (tier A 6, liquid 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 · Si–W system page · Markdown · field reference

Phases of the Si–W system (7)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
DIAMOND_A4 phase:si-w:a4-diamond	C (diamond) · A4 · cF8 · Fd-3m (227)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–1709.42 K, x(W) 0–0	15	4
BCC_A2 phase:si-w:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–3999.89 K, x(W) 0.93612–1	14	4
FCC_A1 phase:si-w:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 4 calculated diagram(s)	0	4
HCP_A3 phase:si-w:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 4 calculated diagram(s)	0	4
LIQUID phase:si-w:liquid	liquid	liquid	stable in 4 of 4 calculated diagram(s): 1660.93–4000 K, x(W) 0–1	63	4
SI2W_C11B phase:si-w:si2w-c11b	MoSi2 · C11_b · tI6 · I4/mmm (139)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–2432.8 K, x(W) 0.33333–0.33333	34	4
SI3W5_D8M phase:si-w:si3w5-d8m	W5Si3 · D8_m · tI32 · I4/mcm (140)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–2593.75 K, x(W) 0.59955–0.625	33	4

DIAMOND_A4 (Si–W)

Id: phase:si-w: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 4 of 4 calculated diagram(s): 300–1709.42 K, x(W) 0–0
Literature: 15 values (15 accepted) from 3 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:si-w:a4-diamond, corpus:phase:si-w:diamond-a4
paper: paper:10.1007/s11669-009-9579-x:Si, paper:10.1016/0364-5916(89)90007-2:Si(dia), paper:10.1016/j.calphad.2013.04.004:Si
tdb: tdb:SiW-03Che-LB.tdb:DIAMOND_A4, tdb:SiW-09Guo.tdb:DIAMOND_A4, tdb:SiW-13Li.tdb:DIAMOND_A4, tdb:SiW-89Vah.tdb:DIAMOND_A4

TDB models of DIAMOND_A4 (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: DIAMOND_A4, type code %, sha256 980d470108b93560…

41: PHASE DIAMOND_A4 % 1 1 !
42: CONST DIAMOND_A4 : SI : !

SiW-09Guo.tdb: DIAMOND_A4, type code %, sha256 5f6d911f9b506958…

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

SiW-13Li.tdb: DIAMOND_A4, type code %, sha256 6cb14cc0019fd856…

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

SiW-89Vah.tdb: DIAMOND_A4, type code %, sha256 1b97c566f7b1735c…

47: PHASE DIAMOND_A4 % 1 1 !
48: CONST DIAMOND_A4 : SI : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase; reports values for this phase
doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase; reports values for this phase

BCC_A2 (Si–W)

Id: phase:si-w:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 300–3999.89 K, x(W) 0.93612–1
Literature: 14 values (14 accepted) from 3 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:si-w:bcc-a2
paper: paper:10.1007/s11669-009-9579-x:(W), paper:10.1016/0364-5916(89)90007-2:W(bcc), paper:10.1016/0364-5916(89)90007-2:bcc, paper:10.1016/j.calphad.2013.04.004:Bcc
tdb: tdb:SiW-03Che-LB.tdb:BCC_A2, tdb:SiW-09Guo.tdb:BCC_A2, tdb:SiW-13Li.tdb:BCC_A2, tdb:SiW-89Vah.tdb:BCC_A2

TDB models of BCC_A2 (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: BCC_A2, type code %B, sha256 980d470108b93560…

31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : SI W% : VA : !

SiW-09Guo.tdb: BCC_A2, type code %B, sha256 5f6d911f9b506958…

36: PHASE BCC_A2 %B 2 1 3 !
37: CONST BCC_A2 : SI W% : VA : !

SiW-13Li.tdb: BCC_A2, type code %B, sha256 6cb14cc0019fd856…

34: PHASE BCC_A2 %B 2 1 3 !
35: CONST BCC_A2 : SI W% : VA : !

SiW-89Vah.tdb: BCC_A2, type code %B, sha256 1b97c566f7b1735c…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : SI W% : VA : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase; reports values for this phase
doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase; reports values for this phase

FCC_A1 (Si–W)

Id: phase:si-w: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 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:si-w:fcc-a1
tdb: tdb:SiW-03Che-LB.tdb:FCC_A1, tdb:SiW-09Guo.tdb:FCC_A1, tdb:SiW-13Li.tdb:FCC_A1, tdb:SiW-89Vah.tdb:FCC_A1

TDB models of FCC_A1 (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: FCC_A1, type code %A, sha256 980d470108b93560…

26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : SI W : VA : !

SiW-09Guo.tdb: FCC_A1, type code %A, sha256 5f6d911f9b506958…

31: PHASE FCC_A1 %A 2 1 1 !
32: CONST FCC_A1 : SI W : VA : !

SiW-13Li.tdb: FCC_A1, type code %A, sha256 6cb14cc0019fd856…

29: PHASE FCC_A1 %A 2 1 1 !
30: CONST FCC_A1 : SI W : VA : !

SiW-89Vah.tdb: FCC_A1, type code %A, sha256 1b97c566f7b1735c…

32: PHASE FCC_A1 %A 2 1 1 !
33: CONST FCC_A1 : SI W : VA : !

Example references (3 of 3; assessments first):

doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase
doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase

HCP_A3 (Si–W)

Id: phase:si-w: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 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:si-w:hcp-a3
tdb: tdb:SiW-03Che-LB.tdb:HCP_A3, tdb:SiW-09Guo.tdb:HCP_A3, tdb:SiW-13Li.tdb:HCP_A3, tdb:SiW-89Vah.tdb:HCP_A3

TDB models of HCP_A3 (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: HCP_A3, type code %A, sha256 980d470108b93560…

36: PHASE HCP_A3 %A 2 1 0.5 !
37: CONST HCP_A3 : SI W : VA : !

SiW-09Guo.tdb: HCP_A3, type code %A, sha256 5f6d911f9b506958…

41: PHASE HCP_A3 %A 2 1 0.5 !
42: CONST HCP_A3 : SI W : VA : !

SiW-13Li.tdb: HCP_A3, type code %A, sha256 6cb14cc0019fd856…

39: PHASE HCP_A3 %A 2 1 0.5 !
40: CONST HCP_A3 : SI W : VA : !

SiW-89Vah.tdb: HCP_A3, type code %A, sha256 1b97c566f7b1735c…

42: PHASE HCP_A3 %A 2 1 0.5 !
43: CONST HCP_A3 : SI W : VA : !

Example references (3 of 3; assessments first):

doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase
doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase

LIQUID (Si–W)

Id: phase:si-w:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 1660.93–4000 K, x(W) 0–1
Literature: 63 values (63 accepted) from 3 papers
Interactive: phase registry entry

Names (8): corpus: corpus:phase:si-w:liquid
paper: paper:10.1007/s11669-009-9579-x:L, paper:10.1016/0364-5916(89)90007-2:L, paper:10.1016/j.calphad.2013.04.004:L
tdb: tdb:SiW-03Che-LB.tdb:LIQUID, tdb:SiW-09Guo.tdb:LIQUID, tdb:SiW-13Li.tdb:LIQUID, tdb:SiW-89Vah.tdb:LIQUID

TDB models of LIQUID (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: LIQUID, type code %, sha256 980d470108b93560…

21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : SI W : !

SiW-09Guo.tdb: LIQUID, type code %, sha256 5f6d911f9b506958…

26: PHASE LIQUID:L % 1 1 !
27: CONST LIQUID:L : SI W : !

SiW-13Li.tdb: LIQUID, type code %, sha256 6cb14cc0019fd856…

24: PHASE LIQUID:L % 1 1 !
25: CONST LIQUID:L : SI W : !

SiW-89Vah.tdb: LIQUID, type code %, sha256 1b97c566f7b1735c…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : SI W : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase; reports values for this phase
doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase; reports values for this phase

SI2W_C11B (Si–W)

Id: phase:si-w:si2w-c11b; status assigned
Structure: MoSi2 · C11_b · tI6 · I4/mmm (139); type st:c11-b-mosi2-ti6; tier A: standard phase name; confidence high
Caveat: DFT agrees: on-hull mp-aaaaacki and oqmd-5147, space group 139
Stoichiometry: Si 0.6667, W 0.3333
Stability: stable in 4 of 4 calculated diagram(s): 300–2432.8 K, x(W) 0.33333–0.33333
Literature: 34 values (34 accepted) from 3 papers
Interactive: phase registry entry

Names (11): corpus: corpus:phase:si-w:si2w-c11b
mp: mp:mp-aaaaacki
oqmd: oqmd:oqmd-5147
paper: paper:10.1007/s11669-009-9579-x:WSi2, paper:10.1016/0364-5916(89)90007-2:Si2W, paper:10.1016/j.calphad.2013.04.004:Si2W, paper:10.1016/j.calphad.2013.04.004:WSi2
tdb: tdb:SiW-03Che-LB.tdb:SI2W_C11B, tdb:SiW-09Guo.tdb:SI2W_C11B, tdb:SiW-13Li.tdb:SI2W_C11B, tdb:SiW-89Vah.tdb:SI2W_C11B

TDB models of SI2W_C11B (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: SI2W_C11B, type code %, sha256 980d470108b93560…

46: PHASE SI2W_C11B % 2 2 1 !
47: CONST SI2W_C11B : SI : W : !

SiW-09Guo.tdb: SI2W_C11B, type code %, sha256 5f6d911f9b506958…

51: PHASE SI2W_C11B % 2 2 1 !
52: CONST SI2W_C11B : SI : W : !

SiW-13Li.tdb: SI2W_C11B, type code %, sha256 6cb14cc0019fd856…

49: PHASE SI2W_C11B % 2 2 1 !
50: CONST SI2W_C11B : SI : W : !

SiW-89Vah.tdb: SI2W_C11B, type code %, sha256 1b97c566f7b1735c…

52: PHASE SI2W_C11B % 2 2 1 !
53: CONST SI2W_C11B : SI : W : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase; reports values for this phase
doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase; reports values for this phase

SI3W5_D8M (Si–W)

Id: phase:si-w:si3w5-d8m; status assigned
Structure: W5Si3 · D8_m · tI32 · I4/mcm (140); type st:d8-m-w5si3-ti32; tier A: standard phase name; confidence high
Caveat: partitioned order/disorder model in SiW-13Li.tdb also describes the disordered state
Stability: stable in 4 of 4 calculated diagram(s): 300–2593.75 K, x(W) 0.59955–0.625
Literature: 33 values (33 accepted) from 3 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:si-w:si3w5-d8m
paper: paper:10.1007/s11669-009-9579-x:W5Si3, paper:10.1016/0364-5916(89)90007-2:Si3W5, paper:10.1016/j.calphad.2013.04.004:Si3W5, paper:10.1016/j.calphad.2013.04.004:W5Si3
tdb: tdb:SiW-03Che-LB.tdb:SI3W5_D8M, tdb:SiW-09Guo.tdb:SI3W5_D8M, tdb:SiW-13Li.tdb:SI3W5_D8M, tdb:SiW-89Vah.tdb:SI3W5_D8M

TDB models of SI3W5_D8M (4): PHASE and CONSTITUENT statements as written

SiW-03Che-LB.tdb: SI3W5_D8M, type code %, sha256 980d470108b93560…

51: PHASE SI3W5_D8M % 2 3 5 !
52: CONST SI3W5_D8M : SI : W : !

SiW-09Guo.tdb: SI3W5_D8M, type code %, sha256 5f6d911f9b506958…

56: PHASE SI3W5_D8M % 2 3 5 !
57: CONST SI3W5_D8M : SI : W : !

SiW-13Li.tdb: SI3W5_D8M, type code %, sha256 6cb14cc0019fd856…

54: PHASE SI3W5_D8M % 3 4 1 3 !
55: CONST SI3W5_D8M : W : SI W% : SI% W : !

SiW-89Vah.tdb: SI3W5_D8M, type code %, sha256 1b97c566f7b1735c…

57: PHASE SI3W5_D8M % 2 3 5 !
58: CONST SI3W5_D8M : SI : W : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(89)90007-2 C. Vahlas, P.Y. Chevalier, E. Blanquet, A thermodynamic evaluation of four Si-M (M = Mo, Ta, Ti, W) binary systems, Calphad 13, 273-292 (1989).
assessment that models this phase; reports values for this phase
doi:10.1007/s11669-009-9579-x Zhongnan Guo, Wenxia Yuan, Yu Sun, Zhoufei Cai, Zhiyu Qiao, Thermodynamic Assessment of the Si-Ta and Si-W Systems, J. Phase Equilib. Diffus. 30, 564-570 (2009).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2013.04.004 Yan Li, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic optimization of the Nb–Si–W ternary system, Calphad 43, 112-123 (2013).
assessment that models this phase; reports 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}
}