La–O phases

15 phases (tier A 3, tier C 1, liquid 2, gas 2, needs_review 7); 11 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 · La–O system page · Markdown · field reference

Phases of the La–O system (15)
Phase	Structure	Basis	Stability (calculated)	TDB models
B_R2O3 phase:la-o:b-r2o3		needs_review	not stable in 1 calculated diagram(s)	1
BCC_A2 phase:la-o:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–2500 K, x(O) 0–0.75	4
A_R2O3_D52 phase:la-o:d52-a-r2o3	A-La2O3 · D5_2 · hP5 · P-3m1 (164)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–301 K, x(O) 0.6–0.6	2
C_R2O3_D53 phase:la-o:d53-c-r2o3		needs_review	not stable in 1 calculated diagram(s)	1
DHCP phase:la-o:dhcp-a3	alpha-La · A3' · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–553 K, x(O) 0–0.00457	4
FCC_A1 phase:la-o:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 550–1179 K, x(O) 0–0.07859	4
GAS phase:la-o:gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300–2500 K, x(O) 1–1	4
H_R2O3 phase:la-o:h-r2o3		needs_review	not stable in 1 calculated diagram(s)	2
ION phase:la-o:ion	liquid	liquid	stable in 1 of 2 calculated diagram(s): 1169.18–2500 K, x(O) 0.0027–0.53814	4
A_LA2O3_D52 phase:la-o:la2o3-d52-a		needs_review	stable in 1 of 1 calculated diagram(s): 300–2312.72 K, x(O) 0.5879–0.6	2
H_LA2O3 phase:la-o:la2o3-h		needs_review	stable in 1 of 1 calculated diagram(s): 2312.72–2382.84 K, x(O) 0.58814–0.59998	2
X_LA2O3 phase:la-o:la2o3-x		needs_review	stable in 1 of 1 calculated diagram(s): 2382.84–2500 K, x(O) 0.58852–0.59997	2
LIQUID phase:la-o:liquid	liquid	liquid	not stable in 2 calculated diagram(s)	4
O2GAS phase:la-o:o2gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300–1185 K, x(O) 1–1	4
X_R2O3 phase:la-o:r2o3-x		needs_review	stable in 1 of 1 calculated diagram(s): 2380.5–2500 K, x(O) 0.6–0.6	2

B_R2O3 (La–O)

Id: phase:la-o:b-r2o3; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:B,R2O3; no_structure_token
Candidate (sgte_mmc2): B-Sm2O3 · mC30 · C2/m (12) — Hallstedt 2025 mmc2 row for B_R2O3: (Ce,Y)2O3 (doesn't necessarily exist), Dy2O3, Eu2O3, Gd2O3, Ho2O3, Sm2O3, Tb2O3
Candidate (sgte_mmc2): B-Sm2O3 · mC30 · C2/m (12) — Hallstedt 2025 mmc2 row for B_R2O3: (La,Y)2O3
Candidate (sgte_mmc2): B-Sm2O3 · mC30 · C2/m (12) — Hallstedt 2025 mmc2 row for B_R2O3: Gd2O3, (Nd,Y)2O3, Sm2O3
Candidate (tdb_comment): B-Sm2O3 · mC30 · C2/m — LaO-07Zin.tdb: 'Prototype B-Sm2O3 (mC30, C2/m)'
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:la-o:b-r2o3
tdb: tdb:LaO-07Zin.tdb:B_R2O3

TDB models of B_R2O3 (1): PHASE and CONSTITUENT statements as written

LaO-07Zin.tdb: B_R2O3, type code %, sha256 c8176e51a3d7e851…

72: PHASE B_R2O3:I % 2 2 3 !
73: CONST B_R2O3:I : LA+3 : O-2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase

BCC_A2 (La–O)

Id: phase:la-o: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 2 of 2 calculated diagram(s): 300–2500 K, x(O) 0–0.75
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:bcc-a2
tdb: tdb:LaO-01Gru.tdb:BCC_A2, tdb:LaO-05Che.tdb:BCC_A2, tdb:LaO-07Zin.tdb:BCC_A2, tdb:LaO-23Nak.tdb:BCC_A2

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

LaO-01Gru.tdb: BCC_A2, type code %B, sha256 dd70787d0d64865c…

60: PHASE BCC_A2 %B 2 1 1.5 !
61: CONST BCC_A2 : LA : O VA% : !

LaO-05Che.tdb: BCC_A2, type code %B, sha256 1155c814b96cef9e…

63: PHASE BCC_A2 %B 2 1 1.5 !
64: CONST BCC_A2 : LA : O VA% : !

LaO-07Zin.tdb: BCC_A2, type code %B, sha256 c8176e51a3d7e851…

57: PHASE BCC_A2 %B 2 1 3 !
58: CONST BCC_A2 : LA : O VA% : !

LaO-23Nak.tdb: BCC_A2, type code %B, sha256 adfa607e0c6b94f2…

68: PHASE BCC_A2 %B 2 1 1.5 !
69: CONST BCC_A2 : LA : VA : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

A_R2O3_D52 (La–O)

Id: phase:la-o:d52-a-r2o3; status assigned
Structure: A-La2O3 · D5_2 · hP5 · P-3m1 (164); type st:d5-2-a-la2o3-hp5; 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:A,R2O3); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: stable in 1 of 1 calculated diagram(s): 300–301 K, x(O) 0.6–0.6
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:d52-a-r2o3
tdb: tdb:LaO-05Che.tdb:A_R2O3_D52, tdb:LaO-07Zin.tdb:A_R2O3_D52

TDB models of A_R2O3_D52 (2): PHASE and CONSTITUENT statements as written

LaO-05Che.tdb: A_R2O3_D52, type code %, sha256 1155c814b96cef9e…

73: PHASE A_R2O3_D52:I % 3 2 3 1 !
74: CONST A_R2O3_D52:I : LA LA+3% : O-2% VA : O-2 VA% : !

LaO-07Zin.tdb: A_R2O3_D52, type code %, sha256 c8176e51a3d7e851…

67: PHASE A_R2O3_D52:I % 2 2 3 !
68: CONST A_R2O3_D52:I : LA+3 : O-2 : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase

C_R2O3_D53 (La–O)

Id: phase:la-o:d53-c-r2o3; status needs_review
No structure assigned. Why: unrecognised_name_tokens:C,R2O3
Candidate (name_token): Mn2O3 · D5_3 · cI80 · Ia-3 (206) — Strukturbericht/word 'D53' in the TDB name
Candidate (sgte_mmc2): Mn2O3 · D5_3 · cI80 · Ia-3 (206) — Hallstedt 2025 mmc2 row for C_R2O3_D53: Ce3O5, Y2O3
Candidate (sgte_mmc2): Mn2O3 · D5_3 · cI80 · Ia-3 (206) — Hallstedt 2025 mmc2 row for C_R2O3_D53: Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, Lu2O3, Sc2O3, Sm2O3, Tb2O3, Tm2O3, Yb2O3
Candidate (sgte_mmc2): Mn2O3 · D5_3 · cI80 · Ia-3 (206) — Hallstedt 2025 mmc2 row for C_R2O3_D53: Gd2O3, Mn2O3, Pr3O5 (sigma), Y2O3
Candidate (sgte_mmc2): Mn2O3 · D5_3 · cI80 · Ia-3 (206) — Hallstedt 2025 mmc2 row for C_R2O3_D53: Mn2O3,Y2O3
Candidate (tdb_comment): Mn2O3 · cI80 · Ia-3 — LaO-07Zin.tdb: 'Prototype Mn2O3 (cI80, Ia-3)'
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:la-o:d53-c-r2o3
tdb: tdb:LaO-07Zin.tdb:C_R2O3_D53

TDB models of C_R2O3_D53 (1): PHASE and CONSTITUENT statements as written

LaO-07Zin.tdb: C_R2O3_D53, type code %, sha256 c8176e51a3d7e851…

77: PHASE C_R2O3_D53:I % 2 2 3 !
78: CONST C_R2O3_D53:I : LA+3 : O-2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase

DHCP (La–O)

Id: phase:la-o:dhcp-a3; status assigned
Structure: alpha-La · A3' · hP4 · P6_3/mmc (194); type st:a3-alpha-la-hp4; tier A: standard phase name; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–553 K, x(O) 0–0.00457
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:dhcp-a3
tdb: tdb:LaO-01Gru.tdb:DHCP, tdb:LaO-05Che.tdb:DHCP, tdb:LaO-07Zin.tdb:DHCP, tdb:LaO-23Nak.tdb:DHCP

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

LaO-01Gru.tdb: DHCP, type code %, sha256 dd70787d0d64865c…

65: PHASE DHCP % 2 1 0.5 !
66: CONST DHCP : LA : VA% O : !

LaO-05Che.tdb: DHCP, type code %, sha256 1155c814b96cef9e…

68: PHASE DHCP % 2 1 0.5 !
69: CONST DHCP : LA : VA% O : !

LaO-07Zin.tdb: DHCP, type code %, sha256 c8176e51a3d7e851…

62: PHASE DHCP % 2 1 0.5 !
63: CONST DHCP : LA : VA% O : !

LaO-23Nak.tdb: DHCP, type code %, sha256 adfa607e0c6b94f2…

73: PHASE DHCP % 2 1 0.5 !
74: CONST DHCP : LA : VA : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

FCC_A1 (La–O)

Id: phase:la-o: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 2 of 2 calculated diagram(s): 550–1179 K, x(O) 0–0.07859
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:fcc-a1
tdb: tdb:LaO-01Gru.tdb:FCC_A1, tdb:LaO-05Che.tdb:FCC_A1, tdb:LaO-07Zin.tdb:FCC_A1, tdb:LaO-23Nak.tdb:FCC_A1

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

LaO-01Gru.tdb: FCC_A1, type code %A, sha256 dd70787d0d64865c…

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

LaO-05Che.tdb: FCC_A1, type code %A, sha256 1155c814b96cef9e…

57: PHASE FCC_A1 %A 2 1 1 !
58: CONST FCC_A1 : LA : O VA% : !

LaO-07Zin.tdb: FCC_A1, type code %A, sha256 c8176e51a3d7e851…

52: PHASE FCC_A1 %A 2 1 1 !
53: CONST FCC_A1 : LA : O VA% : !

LaO-23Nak.tdb: FCC_A1, type code %A, sha256 adfa607e0c6b94f2…

62: PHASE FCC_A1 %A 2 1 1 !
63: CONST FCC_A1 : LA : VA : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

GAS (La–O)

Id: phase:la-o:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–2500 K, x(O) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:gas
tdb: tdb:LaO-01Gru.tdb:GAS, tdb:LaO-05Che.tdb:GAS, tdb:LaO-07Zin.tdb:GAS, tdb:LaO-23Nak.tdb:GAS

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

LaO-01Gru.tdb: GAS, type code %, sha256 dd70787d0d64865c…

83: PHASE GAS:G % 1 1 !
84: CONST GAS:G : LA LAO LA2O LA2O2 O O2% O3 : !

LaO-05Che.tdb: GAS, type code %, sha256 1155c814b96cef9e…

87: PHASE GAS:G % 1 1 !
88: CONST GAS:G : LA LAO LA2O LA2O2 O O2% O3 : !

LaO-07Zin.tdb: GAS, type code %, sha256 c8176e51a3d7e851…

91: PHASE GAS:G % 1 1 !
92: CONST GAS:G : LA LAO LA2O LA2O2 O O2% O3 : !

LaO-23Nak.tdb: GAS, type code %, sha256 adfa607e0c6b94f2…

91: PHASE GAS:G % 1 1 !
92: CONST GAS:G : LA LAO LA2O LA2O2 O O2% O3 : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

H_R2O3 (La–O)

Id: phase:la-o:h-r2o3; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:H,R2O3; no_structure_token
Candidate (sgte_mmc2): H-La2O3 · hP10 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for H_R2O3: Ce2O3, H-Y2O3
Candidate (sgte_mmc2): H-La2O3 · hP10 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for H_R2O3: Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, Nd2O3, Pr2O3, Sm2O3, Tb2O3, Tm2O3, Yb2O3
Candidate (sgte_mmc2): H-La2O3 · hP10 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for H_R2O3: Gd2O3, Nd2O3, Sm2O3
Candidate (sgte_mmc2): H-La2O3 · hP10 · P6_3/mmc (194) — Hallstedt 2025 mmc2 row for H_R2O3: H-La2O3, H-Y2O3
Candidate (tdb_comment): H-La2O3 · hP10 · P6_3/mmc — LaO-05Che.tdb: 'Prototype H-La2O3 (hP10, P6_3/mmc)'
Candidate (tdb_comment): H-La2O3 · hP10 · P6_3/mmc — LaO-07Zin.tdb: 'Prototype H-La2O3 (hP10, P6_3/mmc)'
Stability: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:h-r2o3
tdb: tdb:LaO-05Che.tdb:H_R2O3, tdb:LaO-07Zin.tdb:H_R2O3

TDB models of H_R2O3 (2): PHASE and CONSTITUENT statements as written

LaO-05Che.tdb: H_R2O3, type code %, sha256 1155c814b96cef9e…

78: PHASE H_R2O3:I % 3 2 3 1 !
79: CONST H_R2O3:I : LA LA+3% : O-2% VA : O-2 VA% : !

LaO-07Zin.tdb: H_R2O3, type code %, sha256 c8176e51a3d7e851…

82: PHASE H_R2O3:I % 2 2 3 !
83: CONST H_R2O3:I : LA+3 : O-2 : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase

ION (La–O)

Id: phase:la-o:ion; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 2 calculated diagram(s): 1169.18–2500 K, x(O) 0.0027–0.53814
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:ion
tdb: tdb:LaO-01Gru.tdb:ION, tdb:LaO-05Che.tdb:ION, tdb:LaO-07Zin.tdb:ION, tdb:LaO-23Nak.tdb:ION

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

LaO-01Gru.tdb: ION, type code %, sha256 dd70787d0d64865c…

46: PHASE ION:Y % 2 1 1 !
47: CONST ION:Y : LA+3 : O-2 VA : !

LaO-05Che.tdb: ION, type code %, sha256 1155c814b96cef9e…

49: PHASE ION:Y % 2 1 1 !
50: CONST ION:Y : LA+3 : O-2 VA : !

LaO-07Zin.tdb: ION, type code %, sha256 c8176e51a3d7e851…

44: PHASE ION:Y % 2 1 1 !
45: CONST ION:Y : LA+3 : O-2 VA : !

LaO-23Nak.tdb: ION, type code %, sha256 adfa607e0c6b94f2…

54: PHASE ION:Y % 2 1 1 !
55: CONST ION:Y : LA+3 : O-2 VA : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

A_LA2O3_D52 (La–O)

Id: phase:la-o:la2o3-d52-a; status needs_review
No structure assigned. Why: unrecognised_name_tokens:A
Candidate (dft_mp): Ia-3 (206) — on-hull MP La2O3 at x(O)=0.6000
Candidate (dft_oqmd): Ia-3 (206) — on-hull OQMD La2 O3 at x(O)=0.6000
Candidate (name_token): A-La2O3 · D5_2 · hP5 · P-3m1 (164) — Strukturbericht/word 'D52' in the TDB name
Candidate (tdb_comment): A-La2O3 · hP5 · P-3m1 — LaO-01Gru.tdb: 'Prototype A-La2O3 (hP5, P-3m1)'
Candidate (tdb_comment): A-La2O3 · hP5 · P-3m1 — LaO-23Nak.tdb: 'Prototype A-La2O3 (hP5, P-3m1)'
Stability: stable in 1 of 1 calculated diagram(s): 300–2312.72 K, x(O) 0.5879–0.6
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:la2o3-d52-a
tdb: tdb:LaO-01Gru.tdb:A_LA2O3_D52, tdb:LaO-23Nak.tdb:A_LA2O3_D52

TDB models of A_LA2O3_D52 (2): PHASE and CONSTITUENT statements as written

LaO-01Gru.tdb: A_LA2O3_D52, type code %, sha256 dd70787d0d64865c…

70: PHASE A_LA2O3_D52:I % 2 2 3 !
71: CONST A_LA2O3_D52:I : LA+2 LA+3 : O-2 VA : !

LaO-23Nak.tdb: A_LA2O3_D52, type code %, sha256 adfa607e0c6b94f2…

78: PHASE A_LA2O3_D52:I % 2 2 3 !
79: CONST A_LA2O3_D52:I : LA+2 LA+3 : O-2 VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

H_LA2O3 (La–O)

Id: phase:la-o:la2o3-h; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:H; no_structure_token
Candidate (tdb_comment): H-La2O3 · hP10 · P6_3/mmc — LaO-01Gru.tdb: 'Prototype H-La2O3 (hP10, P6_3/mmc)'
Candidate (tdb_comment): H-La2O3 · hP10 · P6_3/mmc — LaO-23Nak.tdb: 'Prototype H-La2O3 (hP10, P6_3/mmc)'
Stability: stable in 1 of 1 calculated diagram(s): 2312.72–2382.84 K, x(O) 0.58814–0.59998
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:la2o3-h
tdb: tdb:LaO-01Gru.tdb:H_LA2O3, tdb:LaO-23Nak.tdb:H_LA2O3

TDB models of H_LA2O3 (2): PHASE and CONSTITUENT statements as written

LaO-01Gru.tdb: H_LA2O3, type code %, sha256 dd70787d0d64865c…

75: PHASE H_LA2O3:I % 2 2 3 !
76: CONST H_LA2O3:I : LA+2 LA+3 : O-2 VA : !

LaO-23Nak.tdb: H_LA2O3, type code %, sha256 adfa607e0c6b94f2…

83: PHASE H_LA2O3:I % 2 2 3 !
84: CONST H_LA2O3:I : LA+2 LA+3 : O-2 VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

X_LA2O3 (La–O)

Id: phase:la-o:la2o3-x; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:X; no_structure_token
Candidate (tdb_comment): Nd2O3 · cI26 · Im-3m — LaO-01Gru.tdb: 'Prototype Nd2O3 (cI26, Im-3m)'
Candidate (tdb_comment): Nd2O3 · cI26 · Im-3m — LaO-23Nak.tdb: 'Prototype Nd2O3 (cI26, Im-3m)'
Stability: stable in 1 of 1 calculated diagram(s): 2382.84–2500 K, x(O) 0.58852–0.59997
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:la2o3-x
tdb: tdb:LaO-01Gru.tdb:X_LA2O3, tdb:LaO-23Nak.tdb:X_LA2O3

TDB models of X_LA2O3 (2): PHASE and CONSTITUENT statements as written

LaO-01Gru.tdb: X_LA2O3, type code %, sha256 dd70787d0d64865c…

80: PHASE X_LA2O3:I % 2 2 3 !
81: CONST X_LA2O3:I : LA+2 LA+3 : O-2 VA : !

LaO-23Nak.tdb: X_LA2O3, type code %, sha256 adfa607e0c6b94f2…

88: PHASE X_LA2O3:I % 2 2 3 !
89: CONST X_LA2O3:I : LA+2 LA+3 : O-2 VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

LIQUID (La–O)

Id: phase:la-o:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stoichiometry: La 1.0000
Stability: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:liquid
tdb: tdb:LaO-01Gru.tdb:LIQUID, tdb:LaO-05Che.tdb:LIQUID, tdb:LaO-07Zin.tdb:LIQUID, tdb:LaO-23Nak.tdb:LIQUID

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

LaO-01Gru.tdb: LIQUID, type code %, sha256 dd70787d0d64865c…

49: PHASE LIQUID:L % 1 1 !
50: CONST LIQUID:L : LA : !

LaO-05Che.tdb: LIQUID, type code %, sha256 1155c814b96cef9e…

52: PHASE LIQUID:L % 1 1 !
53: CONST LIQUID:L : LA : !

LaO-07Zin.tdb: LIQUID, type code %, sha256 c8176e51a3d7e851…

47: PHASE LIQUID:L % 1 1 !
48: CONST LIQUID:L : LA : !

LaO-23Nak.tdb: LIQUID, type code %, sha256 adfa607e0c6b94f2…

57: PHASE LIQUID:L % 1 1 !
58: CONST LIQUID:L : LA : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

O2GAS (La–O)

Id: phase:la-o:o2gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–1185 K, x(O) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:la-o:o2gas
tdb: tdb:LaO-01Gru.tdb:O2GAS, tdb:LaO-05Che.tdb:O2GAS, tdb:LaO-07Zin.tdb:O2GAS, tdb:LaO-23Nak.tdb:O2GAS

TDB models of O2GAS (4): PHASE and CONSTITUENT statements as written

LaO-01Gru.tdb: O2GAS, type code %, sha256 dd70787d0d64865c…

86: PHASE O2GAS % 1 1 !
87: CONST O2GAS : O2 : !

LaO-05Che.tdb: O2GAS, type code %, sha256 1155c814b96cef9e…

90: PHASE O2GAS % 1 1 !
91: CONST O2GAS : O2 : !

LaO-07Zin.tdb: O2GAS, type code %, sha256 c8176e51a3d7e851…

94: PHASE O2GAS % 1 1 !
95: CONST O2GAS : O2 : !

LaO-23Nak.tdb: O2GAS, type code %, sha256 adfa607e0c6b94f2…

94: PHASE O2GAS % 1 1 !
95: CONST O2GAS : O2 : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.calphad.2023.102636 Calphad, 83, 102636(2023).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
assessment that models this phase
doi:10.1361/105497101770338950 A. Nicholas Grundy, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic assessment of the lanthanum-oxygen system, JPE 22, 105-113 (2001).
assessment that models this phase

X_R2O3 (La–O)

Id: phase:la-o:r2o3-x; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:R2O3,X; no_structure_token
Candidate (dft_mp): Ia-3 (206) — on-hull MP La2O3 at x(O)=0.6000
Candidate (dft_oqmd): Ia-3 (206) — on-hull OQMD La2 O3 at x(O)=0.6000
Candidate (sgte_mmc2): Nd2O3 · cI26 · Im-3m (229) — Hallstedt 2025 mmc2 row for X_R2O3: Ce2O3
Candidate (sgte_mmc2): Nd2O3 · cI26 · Im-3m (229) — Hallstedt 2025 mmc2 row for X_R2O3: Dy2O3, Eu2O3, Gd2O3, Nd2O3, Pr2O3, Sm2O3, Tb2O3
Candidate (sgte_mmc2): Nd2O3 · cI26 · Im-3m (229) — Hallstedt 2025 mmc2 row for X_R2O3: Gd2O3, Nd2O3, Sm2O3
Candidate (sgte_mmc2): Nd2O3 · cI26 · Im-3m (229) — Hallstedt 2025 mmc2 row for X_R2O3: X-La2O3
Candidate (tdb_comment): Nd2O3 · cI26 · Im-3m — LaO-05Che.tdb: 'Prototype Nd2O3 (cI26, Im-3m)'
Candidate (tdb_comment): Nd2O3 · cI26 · Im-3m — LaO-07Zin.tdb: 'Prototype Nd2O3 (cI26, Im-3m)'
Stability: stable in 1 of 1 calculated diagram(s): 2380.5–2500 K, x(O) 0.6–0.6
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:la-o:r2o3-x
tdb: tdb:LaO-05Che.tdb:X_R2O3, tdb:LaO-07Zin.tdb:X_R2O3

TDB models of X_R2O3 (2): PHASE and CONSTITUENT statements as written

LaO-05Che.tdb: X_R2O3, type code %, sha256 1155c814b96cef9e…

84: PHASE X_R2O3:I % 3 2 3 1 !
85: CONST X_R2O3:I : LA LA+3% : O-2% VA : O-2 VA% : !

LaO-07Zin.tdb: X_R2O3, type code %, sha256 c8176e51a3d7e851…

88: PHASE X_R2O3:I % 2 2 3 !
89: CONST X_R2O3:I : LA+3 : O-2 : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2005.06.006 M. Chen, B. Hallstedt, L.J. Gauckler, Calphad, 29, 103-13(2005).
assessment that models this phase
doi:10.1016/j.pmatsci.2006.09.002 M ZINKEVICH, Thermodynamics of rare earth sesquioxides, Progress in Materials Science 52, 597-647 (2007).
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}
}