O–Si phases

17 phases (tier A 4, liquid 2, gas 2, needs_review 7, unresolved_no_candidates 2); 9 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 · O–Si system page · Markdown · field reference

Phases of the O–Si system (17)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
A_CRISTOBALITE phase:o-si:a-cristobalite		needs_review	no calculated diagram	0	1
A_QUARTZ phase:o-si:a-quartz		needs_review	no calculated diagram	0	1
DIAMOND_A4 phase:o-si:a4-diamond	C (diamond) · A4 · cF8 · Fd-3m (227)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–1687 K, x(O) 0–5e-05	1	3
B_CRISTOBALITE phase:o-si:b-cristobalite		needs_review	no calculated diagram	0	1
B_QUARTZ phase:o-si:b-quartz		needs_review	no calculated diagram	0	1
BCC_A2 phase:o-si:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	3
CRISTOBALITE phase:o-si:cristobalite		needs_review	stable in 2 of 2 calculated diagram(s): 1145.12–1998 K, x(O) 0.66667–0.66667	2	2
FCC_A1 phase:o-si:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	3
GAS phase:o-si:gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300.12–2500 K, x(O) 0.49877–1	3	3
HCP_A3 phase:o-si:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	3
ION phase:o-si:ion	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1469.58–2500 K, x(O) 0–0.66667	0	1
LIQUID phase:o-si:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 1687–2500 K, x(O) 0–0.00064	3	3
O2GAS phase:o-si:o2gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300–1190.12 K, x(O) 1–1	0	3
QUARTZ phase:o-si:quartz		needs_review	stable in 2 of 2 calculated diagram(s): 300–1145.12 K, x(O) 0.66667–0.66667	0	2
SIO_AM phase:o-si:sio-am		unresolved_no_candidates	not stable in 1 calculated diagram(s)	0	1
SIO2_L phase:o-si:sio2-l		unresolved_no_candidates	stable in 1 of 1 calculated diagram(s): 1998–2500 K, x(O) 0.66667–0.66667	0	2
TRIDYMITE phase:o-si:tridymite		needs_review	stable in 1 of 2 calculated diagram(s): 1143.04–1744.11 K, x(O) 0.66667–0.66667	1	2

A_CRISTOBALITE (O–Si)

Id: phase:o-si:a-cristobalite; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:A,CRISTOBALITE; no_structure_token
Candidate (tdb_comment): SiO2 · tP12 · P4_12_12; low — SiO-20Baj-3g.tdb: 'Prototype SiO2 (tP12, P4_12_12; low)'
Stability: no calculated diagram
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-si:a-cristobalite
tdb: tdb:SiO-20Baj-3g.tdb:A_CRISTOBALITE

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

SiO-20Baj-3g.tdb: A_CRISTOBALITE, type code %, sha256 ad6c07bdbf4999c8…

90: PHASE A_CRISTOBALITE % 1 1 !
91: CONST A_CRISTOBALITE : SIO2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

A_QUARTZ (O–Si)

Id: phase:o-si:a-quartz; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:A,QUARTZ; no_structure_token
Candidate (tdb_comment): SiO2 · hP9 · P3_121; alpha — SiO-20Baj-3g.tdb: 'Prototype SiO2 (hP9, P3_121; alpha)'
Stability: no calculated diagram
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-si:a-quartz
tdb: tdb:SiO-20Baj-3g.tdb:A_QUARTZ

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

SiO-20Baj-3g.tdb: A_QUARTZ, type code %, sha256 ad6c07bdbf4999c8…

80: PHASE A_QUARTZ % 1 1 !
81: CONST A_QUARTZ : SIO2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

DIAMOND_A4 (O–Si)

Id: phase:o-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
Stability: stable in 2 of 2 calculated diagram(s): 300–1687 K, x(O) 0–5e-05
Literature: 1 values (1 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:o-si:a4-diamond
paper: paper:10.1016/0364-5916(92)90038-y:(Si)
tdb: tdb:SiO-04Sch.tdb:DIAMOND_A4, tdb:SiO-20Baj-3g.tdb:DIAMOND_A4, tdb:SiO-92Hal.tdb:DIAMOND_A4

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

SiO-04Sch.tdb: DIAMOND_A4, type code %, sha256 0f627cab998ca6d6…

69: PHASE DIAMOND_A4 % 1 1 !
70: CONST DIAMOND_A4 : O SI : !

SiO-20Baj-3g.tdb: DIAMOND_A4, type code %, sha256 ad6c07bdbf4999c8…

70: PHASE DIAMOND_A4 % 1 1 !
71: CONST DIAMOND_A4 : O SI : !

SiO-92Hal.tdb: DIAMOND_A4, type code %, sha256 243e703636b34ae0…

59: PHASE DIAMOND_A4 % 1 1 !
60: CONST DIAMOND_A4 : O SI : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

B_CRISTOBALITE (O–Si)

Id: phase:o-si:b-cristobalite; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:B,CRISTOBALITE; no_structure_token
Candidate (tdb_comment): SiO2 · cF104 · Fd-3m, C9; beta — SiO-20Baj-3g.tdb: 'Prototype SiO2 (cF104, Fd-3m, C9; beta)'
Stability: no calculated diagram
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-si:b-cristobalite
tdb: tdb:SiO-20Baj-3g.tdb:B_CRISTOBALITE

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

SiO-20Baj-3g.tdb: B_CRISTOBALITE, type code %, sha256 ad6c07bdbf4999c8…

95: PHASE B_CRISTOBALITE % 1 1 !
96: CONST B_CRISTOBALITE : SIO2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

B_QUARTZ (O–Si)

Id: phase:o-si:b-quartz; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:B,QUARTZ; no_structure_token
Candidate (tdb_comment): SiO2 · hP9 · P6_222, C8; beta — SiO-20Baj-3g.tdb: 'Prototype SiO2 (hP9, P6_222, C8; beta)'
Stability: no calculated diagram
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-si:b-quartz
tdb: tdb:SiO-20Baj-3g.tdb:B_QUARTZ

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

SiO-20Baj-3g.tdb: B_QUARTZ, type code %, sha256 ad6c07bdbf4999c8…

85: PHASE B_QUARTZ % 1 1 !
86: CONST B_QUARTZ : SIO2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

BCC_A2 (O–Si)

Id: phase:o-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 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:o-si:bcc-a2
tdb: tdb:SiO-04Sch.tdb:BCC_A2, tdb:SiO-20Baj-3g.tdb:BCC_A2, tdb:SiO-92Hal.tdb:BCC_A2

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

SiO-04Sch.tdb: BCC_A2, type code %B, sha256 0f627cab998ca6d6…

59: PHASE BCC_A2 %B 2 1 3 !
60: CONST BCC_A2 : SI : O VA% : !

SiO-20Baj-3g.tdb: BCC_A2, type code %B, sha256 ad6c07bdbf4999c8…

60: PHASE BCC_A2 %B 2 1 3 !
61: CONST BCC_A2 : SI : O VA% : !

SiO-92Hal.tdb: BCC_A2, type code %B, sha256 243e703636b34ae0…

49: PHASE BCC_A2 %B 2 1 3 !
50: CONST BCC_A2 : SI : O VA% : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

CRISTOBALITE (O–Si)

Id: phase:o-si:cristobalite; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:CRISTOBALITE; no_structure_token; sgte_mmc2_rows_disagree
Candidate (sgte_mmc2): SiO2 · C9 · cF24 · Fd-3m (227) — Hallstedt 2025 mmc2 row for CRISTOBALITE: SiO2 (beta cristobalite)
Candidate (sgte_mmc2): SiO2 · tP12 · P4_12_12 (92) — Hallstedt 2025 mmc2 row for CRISTOBALITE: SiO2 (low cristobalite)
Candidate (tdb_comment): SiO2 · cF104 · Fd-3m, C9; beta and tP12, P4_12_12; low — SiO-04Sch.tdb: 'Prototype SiO2 (cF104, Fd-3m, C9; beta and tP12, P4_12_12; low)'
Candidate (tdb_comment): SiO2 · cF104 · Fd-3m, C9; beta and tP12, P4_12_12; low — SiO-92Hal.tdb: 'Prototype SiO2 (cF104, Fd-3m, C9; beta and tP12, P4_12_12; low)'
Stability: stable in 2 of 2 calculated diagram(s): 1145.12–1998 K, x(O) 0.66667–0.66667
Literature: 2 values (1 accepted) from 2 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:o-si:cristobalite
paper: paper:10.1016/0364-5916(92)90038-y:Cristobalite, paper:10.1016/j.jnoncrysol.2003.12.057:cristobalite
tdb: tdb:SiO-04Sch.tdb:CRISTOBALITE, tdb:SiO-92Hal.tdb:CRISTOBALITE

TDB models of CRISTOBALITE (2): PHASE and CONSTITUENT statements as written

SiO-04Sch.tdb: CRISTOBALITE, type code %, sha256 0f627cab998ca6d6…

89: PHASE CRISTOBALITE % 1 1 !
90: CONST CRISTOBALITE : SIO2 : !

SiO-92Hal.tdb: CRISTOBALITE, type code %, sha256 243e703636b34ae0…

64: PHASE CRISTOBALITE % 1 1 !
65: CONST CRISTOBALITE : SIO2 : !

Example references (2 of 2; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase; reports values for this phase

FCC_A1 (O–Si)

Id: phase:o-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 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:o-si:fcc-a1
tdb: tdb:SiO-04Sch.tdb:FCC_A1, tdb:SiO-20Baj-3g.tdb:FCC_A1, tdb:SiO-92Hal.tdb:FCC_A1

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

SiO-04Sch.tdb: FCC_A1, type code %A, sha256 0f627cab998ca6d6…

54: PHASE FCC_A1 %A 2 1 1 !
55: CONST FCC_A1 : SI : O VA% : !

SiO-20Baj-3g.tdb: FCC_A1, type code %A, sha256 ad6c07bdbf4999c8…

55: PHASE FCC_A1 %A 2 1 1 !
56: CONST FCC_A1 : SI : O VA% : !

SiO-92Hal.tdb: FCC_A1, type code %A, sha256 243e703636b34ae0…

44: PHASE FCC_A1 %A 2 1 1 !
45: CONST FCC_A1 : SI : O VA% : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

GAS (O–Si)

Id: phase:o-si:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300.12–2500 K, x(O) 0.49877–1
Literature: 3 values (1 accepted) from 2 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:o-si:gas
paper: paper:10.1016/0364-5916(92)90038-y:Gas, paper:10.1016/j.jnoncrysol.2003.12.057:gas
tdb: tdb:SiO-04Sch.tdb:GAS, tdb:SiO-20Baj-3g.tdb:GAS, tdb:SiO-92Hal.tdb:GAS

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

SiO-04Sch.tdb: GAS, type code %, sha256 0f627cab998ca6d6…

101: PHASE GAS:G % 1 1 !
102: CONST GAS:G : O O2 O3 SI SI2 SI3 SIO SIO2 : !

SiO-20Baj-3g.tdb: GAS, type code %, sha256 ad6c07bdbf4999c8…

101: PHASE GAS:G % 1 1 !
102: CONST GAS:G : O O2 O3 SI SI2 SI3 SIO SIO2 : !

SiO-92Hal.tdb: GAS, type code %, sha256 243e703636b34ae0…

81: PHASE GAS:G % 1 1 !
82: CONST GAS:G : O O2 O3 SI SI2 SI3 SIO SIO2 : !

Example references (3 of 3; assessments first):

doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

HCP_A3 (O–Si)

Id: phase:o-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: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:o-si:hcp-a3
tdb: tdb:SiO-04Sch.tdb:HCP_A3, tdb:SiO-20Baj-3g.tdb:HCP_A3, tdb:SiO-92Hal.tdb:HCP_A3

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

SiO-04Sch.tdb: HCP_A3, type code %, sha256 0f627cab998ca6d6…

64: PHASE HCP_A3 % 2 1 0.5 !
65: CONST HCP_A3 : SI : O VA% : !

SiO-20Baj-3g.tdb: HCP_A3, type code %, sha256 ad6c07bdbf4999c8…

65: PHASE HCP_A3 % 2 1 0.5 !
66: CONST HCP_A3 : SI : O VA% : !

SiO-92Hal.tdb: HCP_A3, type code %, sha256 243e703636b34ae0…

54: PHASE HCP_A3 % 2 1 0.5 !
55: CONST HCP_A3 : SI : O VA% : !

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

ION (O–Si)

Id: phase:o-si:ion; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1469.58–2500 K, x(O) 0–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:o-si:ion
tdb: tdb:SiO-92Hal.tdb:ION

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

SiO-92Hal.tdb: ION, type code %, sha256 243e703636b34ae0…

39: PHASE ION:Y % 2 1 1 !
40: CONST ION:Y : SI+4 : O-2 VA SIO2 : !

Example references (1 of 1; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase

LIQUID (O–Si)

Id: phase:o-si:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 1687–2500 K, x(O) 0–0.00064
Literature: 3 values (1 accepted) from 2 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:o-si:liquid
paper: paper:10.1016/0364-5916(92)90038-y:L1, paper:10.1016/j.jnoncrysol.2003.12.057:liquid
tdb: tdb:SiO-04Sch.tdb:LIQUID, tdb:SiO-20Baj-3g.tdb:LIQUID, tdb:SiO-92Hal.tdb:LIQUID

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

SiO-04Sch.tdb: LIQUID, type code %, sha256 0f627cab998ca6d6…

46: PHASE LIQUID:L % 1 1 !
47: CONST LIQUID:L : O SI : !

SiO-20Baj-3g.tdb: LIQUID, type code %, sha256 ad6c07bdbf4999c8…

47: PHASE LIQUID:L % 1 1 !
48: CONST LIQUID:L : O SI : !

SiO-92Hal.tdb: LIQUID, type code %, sha256 243e703636b34ae0…

36: PHASE LIQUID:L % 1 1 !
37: CONST LIQUID:L : SI : !

Example references (3 of 3; assessments first):

doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase

O2GAS (O–Si)

Id: phase:o-si:o2gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–1190.12 K, x(O) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:o-si:o2gas
tdb: tdb:SiO-04Sch.tdb:O2GAS, tdb:SiO-20Baj-3g.tdb:O2GAS, tdb:SiO-92Hal.tdb:O2GAS

TDB models of O2GAS (3): PHASE and CONSTITUENT statements as written

SiO-04Sch.tdb: O2GAS, type code %, sha256 0f627cab998ca6d6…

98: PHASE O2GAS % 1 1 !
99: CONST O2GAS : O2 :!

SiO-20Baj-3g.tdb: O2GAS, type code %, sha256 ad6c07bdbf4999c8…

98: PHASE O2GAS % 1 1 !
99: CONST O2GAS : O2 :!

SiO-92Hal.tdb: O2GAS, type code %, sha256 243e703636b34ae0…

78: PHASE O2GAS % 1 1 !
79: CONST O2GAS : O2 :!

Example references (3 of 3; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase
doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

QUARTZ (O–Si)

Id: phase:o-si:quartz; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:QUARTZ; no_structure_token; sgte_mmc2_rows_disagree
Candidate (sgte_mmc2): SiO2 · C8 · hP9 · P6_222 (180) — Hallstedt 2025 mmc2 row for QUARTZ: SiO2 (beta quartz)
Candidate (sgte_mmc2): SiO2 · hP9 · P3_121 (152) — Hallstedt 2025 mmc2 row for QUARTZ: SiO2 (alpha quartz)
Candidate (tdb_comment): SiO2 · hP9 · P3_121; alpha and hP9, P6_222, C8; beta — SiO-04Sch.tdb: 'Prototype SiO2 (hP9, P3_121; alpha and hP9, P6_222, C8; beta)'
Candidate (tdb_comment): SiO2 · hP9 · P3_121; alpha and hP9, P6_222, C8; beta — SiO-92Hal.tdb: 'Prototype SiO2 (hP9, P3_121; alpha and hP9, P6_222, C8; beta)'
Stability: stable in 2 of 2 calculated diagram(s): 300–1145.12 K, x(O) 0.66667–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:o-si:quartz
tdb: tdb:SiO-04Sch.tdb:QUARTZ, tdb:SiO-92Hal.tdb:QUARTZ

TDB models of QUARTZ (2): PHASE and CONSTITUENT statements as written

SiO-04Sch.tdb: QUARTZ, type code %, sha256 0f627cab998ca6d6…

84: PHASE QUARTZ % 1 1 !
85: CONST QUARTZ : SIO2 : !

SiO-92Hal.tdb: QUARTZ, type code %, sha256 243e703636b34ae0…

69: PHASE QUARTZ % 1 1 !
70: CONST QUARTZ : SIO2 : !

Example references (2 of 2; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

SIO_AM (O–Si)

Id: phase:o-si:sio-am; status unresolved_no_candidates
No structure assigned. Why: name_has_descriptive_tokens:AM; no_structure_token
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:o-si:sio-am
tdb: tdb:SiO-04Sch.tdb:SIO_AM

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

SiO-04Sch.tdb: SIO_AM, type code %, sha256 0f627cab998ca6d6…

74: PHASE SIO_AM % 1 1 !
75: CONST SIO_AM : SIO : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

SIO2_L (O–Si)

Id: phase:o-si:sio2-l; status unresolved_no_candidates
No structure assigned. Why: name_has_descriptive_tokens:L; no_structure_token
Stability: stable in 1 of 1 calculated diagram(s): 1998–2500 K, x(O) 0.66667–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:o-si:sio2-l
tdb: tdb:SiO-04Sch.tdb:SIO2_L, tdb:SiO-20Baj-3g.tdb:SIO2_L

TDB models of SIO2_L (2): PHASE and CONSTITUENT statements as written

SiO-04Sch.tdb: SIO2_L, type code %, sha256 0f627cab998ca6d6…

79: PHASE SIO2_L % 1 1 !
80: CONST SIO2_L : SIO2 : !

SiO-20Baj-3g.tdb: SIO2_L, type code %, sha256 ad6c07bdbf4999c8…

75: PHASE SIO2_L % 1 1 !
76: CONST SIO2_L : SIO2 : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2019.101716 I. Bajenova, A. Khvan, A. Dinsdale, A. Kondratiev, Calphad, 68, 101716(2020).
assessment that models this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
assessment that models this phase

TRIDYMITE (O–Si)

Id: phase:o-si:tridymite; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:TRIDYMITE; no_structure_token; sgte_mmc2_rows_disagree
Candidate (literature_printed): SiO2 · mC144 — printed with a label mapped to this phase
Candidate (sgte_mmc2): SiO2 · C10 · hP12 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for TRIDYMITE: SiO2 (beta tridymite)
Candidate (sgte_mmc2): SiO2 · mC144 · Cc (9) — Hallstedt 2025 mmc2 row for TRIDYMITE: SiO2 (low tridymite)
Candidate (sgte_mmc2): SiO2 · oC24 · C222_1 (20) — Hallstedt 2025 mmc2 row for TRIDYMITE: SiO2 (high or ortho-I tridymite)
Candidate (tdb_comment): — SiO-04Sch.tdb: 'Prototype SiO2 (mC144, Cc; low and hP12, P6_3/mmc, C10; beta'
Candidate (tdb_comment): — SiO-92Hal.tdb: 'Prototype SiO2 (mC144, Cc; low and hP12, P6_3/mmc, C10; beta'
Stability: stable in 1 of 2 calculated diagram(s): 1143.04–1744.11 K, x(O) 0.66667–0.66667
Literature: 1 values (1 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:o-si:tridymite
paper: paper:10.1016/0364-5916(92)90038-y:Tridymite
tdb: tdb:SiO-04Sch.tdb:TRIDYMITE, tdb:SiO-92Hal.tdb:TRIDYMITE

TDB models of TRIDYMITE (2): PHASE and CONSTITUENT statements as written

SiO-04Sch.tdb: TRIDYMITE, type code %, sha256 0f627cab998ca6d6…

95: PHASE TRIDYMITE % 1 1 !
96: CONST TRIDYMITE : SIO2 : !

SiO-92Hal.tdb: TRIDYMITE, type code %, sha256 243e703636b34ae0…

75: PHASE TRIDYMITE % 1 1 !
76: CONST TRIDYMITE : SIO2 : !

Example references (2 of 2; assessments first):

doi:10.1016/0364-5916(92)90038-Y B. Hallstedt, Calphad, 16, 53-61(1992).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnoncrysol.2003.12.057 S.M. Schnurre, J. Gröbner, R. Schmid-Fetzer, Thermodynamics and phase stability in the Si–O system, Journal of Non-Crystalline Solids 336, 1-25 (2004).
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}
}