Fe–O phases

10 phases (tier A 4, tier C 2, liquid 2, gas 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 · Fe–O system page · Markdown · field reference

Phases of the Fe–O system (10)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
HALITE_B1 phase:fe-o:b1-halite	NaCl · B1 · cF8 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 832.32–1695.47 K, x(O) 0.51203–0.54514	0	8
BCC_A2 phase:fe-o:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–1810.92 K, x(O) 0–0.00029	0	8
CORUNDUM_D51 phase:fe-o:d51-corundum	alpha-Al2O3 · D5_1 · hR10 · R-3c (167)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 2 of 2 calculated diagram(s): 300–1725.46 K, x(O) 0.6–0.6	0	8
FCC_A1 phase:fe-o:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 838.66–1802.44 K, x(O) 0–0.0001	0	8
GAS phase:fe-o:gas	gas	gas	stable in 2 of 2 calculated diagram(s): 1555.46–2500 K, x(O) 0.99965–1	0	8
SPINEL_H11 phase:fe-o:h11-spinel	Al2MgO4 · H1_1 · cF56 · Fd-3m (227)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 2 of 2 calculated diagram(s): 300–1869.74 K, x(O) 0.57089–0.57994	0	8
HCP_A3 phase:fe-o:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	8
ION phase:fe-o:ion	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1642.72–2500 K, x(O) 2e-05–0.58105	0	5
LIQUID phase:fe-o:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1642.22–2500 K, x(O) 2e-05–0.58105	1	4
O2GAS phase:fe-o:o2gas	gas	gas	stable in 1 of 2 calculated diagram(s): 300–445 K, x(O) 1–1	0	8

HALITE_B1 (Fe–O)

Id: phase:fe-o:b1-halite; status assigned
Structure: NaCl · B1 · cF8 · Fm-3m (225); type st:b1-nacl-cf8; tier A: standard phase name; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 832.32–1695.47 K, x(O) 0.51203–0.54514
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:b1-halite
tdb: tdb:FeO-02Luo.tdb:HALITE_B1, tdb:FeO-09Pov.tdb:HALITE_B1, tdb:FeO-23Jia.tdb:HALITE_B1, tdb:FeO-91Sun-LB.tdb:HALITE_B1, tdb:FeO-91Sun-orig.tdb:HALITE_B1, tdb:FeO-93Tay.tdb:HALITE_B1, tdb:FeO-95Kow.tdb:HALITE_B1, tdb:FeO-96Sel.tdb:HALITE_B1

TDB models of HALITE_B1 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: HALITE_B1, type code %, sha256 444e225f4fad778c…

66: PHASE HALITE_B1:I % 2 1 1 !
67: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-09Pov.tdb: HALITE_B1, type code %, sha256 e44f811ba37703b5…

68: PHASE HALITE_B1:I % 2 1 1 !
69: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-23Jia.tdb: HALITE_B1, type code %, sha256 16bc7d5f6d3971df…

65: PHASE HALITE_B1:I % 2 1 1 !
66: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-91Sun-LB.tdb: HALITE_B1, type code %, sha256 0670fd1794f0d2b7…

85: PHASE HALITE_B1:I % 2 1 1 !
86: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-91Sun-orig.tdb: HALITE_B1, type code %, sha256 214f51010594d665…

63: PHASE HALITE_B1:I % 2 1 1 !
64: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-93Tay.tdb: HALITE_B1, type code %, sha256 b5fe5c3fdd6ae4b4…

63: PHASE HALITE_B1:I % 2 1 1 !
64: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-95Kow.tdb: HALITE_B1, type code %, sha256 4b25481824b6c677…

66: PHASE HALITE_B1:I % 2 1 1 !
67: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

FeO-96Sel.tdb: HALITE_B1, type code %, sha256 35ab77bc661f3ab6…

67: PHASE HALITE_B1:I % 2 1 1 !
68: CONST HALITE_B1:I : FE+2% FE+3 VA : O-2 : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

BCC_A2 (Fe–O)

Id: phase:fe-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): 300–1810.92 K, x(O) 0–0.00029
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:bcc-a2
tdb: tdb:FeO-02Luo.tdb:BCC_A2, tdb:FeO-09Pov.tdb:BCC_A2, tdb:FeO-23Jia.tdb:BCC_A2, tdb:FeO-91Sun-LB.tdb:BCC_A2, tdb:FeO-91Sun-orig.tdb:BCC_A2, tdb:FeO-93Tay.tdb:BCC_A2, tdb:FeO-95Kow.tdb:BCC_A2, tdb:FeO-96Sel.tdb:BCC_A2

TDB models of BCC_A2 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: BCC_A2, type code %B, sha256 444e225f4fad778c…

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

FeO-09Pov.tdb: BCC_A2, type code %B, sha256 e44f811ba37703b5…

51: PHASE BCC_A2 %B 2 1 3 !
52: CONST BCC_A2 : FE : O VA% : !

FeO-23Jia.tdb: BCC_A2, type code %B, sha256 16bc7d5f6d3971df…

48: PHASE BCC_A2 %B 2 1 3 !
49: CONST BCC_A2 : FE : O VA% : !

FeO-91Sun-LB.tdb: BCC_A2, type code %B, sha256 0670fd1794f0d2b7…

68: PHASE BCC_A2 %B 2 1 3 !
69: CONST BCC_A2 : FE : O VA% : !

FeO-91Sun-orig.tdb: BCC_A2, type code %B, sha256 214f51010594d665…

46: PHASE BCC_A2 %B 2 1 3 !
47: CONST BCC_A2 : FE O : VA : !

FeO-93Tay.tdb: BCC_A2, type code %B, sha256 b5fe5c3fdd6ae4b4…

46: PHASE BCC_A2 %B 2 1 3 !
47: CONST BCC_A2 : FE O : VA : !

FeO-95Kow.tdb: BCC_A2, type code %B, sha256 4b25481824b6c677…

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

FeO-96Sel.tdb: BCC_A2, type code %B, sha256 35ab77bc661f3ab6…

50: PHASE BCC_A2 %B 2 1 3 !
51: CONST BCC_A2 : FE O : VA : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

CORUNDUM_D51 (Fe–O)

Id: phase:fe-o:d51-corundum; status assigned
Structure: alpha-Al2O3 · D5_1 · hR10 · R-3c (167); type st:d5-1-alpha-al2o3-hr10; 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:CORUNDUM); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: stable in 2 of 2 calculated diagram(s): 300–1725.46 K, x(O) 0.6–0.6
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (10): corpus: corpus:phase:fe-o:d51-corundum, corpus:phase:fe-o:corundum-d51
tdb: tdb:FeO-02Luo.tdb:CORUNDUM_D51, tdb:FeO-09Pov.tdb:CORUNDUM_D51, tdb:FeO-23Jia.tdb:CORUNDUM_D51, tdb:FeO-91Sun-LB.tdb:CORUNDUM_D51, tdb:FeO-91Sun-orig.tdb:CORUNDUM_D51, tdb:FeO-93Tay.tdb:CORUNDUM_D51, tdb:FeO-95Kow.tdb:CORUNDUM_D51, tdb:FeO-96Sel.tdb:CORUNDUM_D51

TDB models of CORUNDUM_D51 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: CORUNDUM_D51, type code %A, sha256 444e225f4fad778c…

60: PHASE CORUNDUM_D51:I %A 2 2 3 !
61: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-09Pov.tdb: CORUNDUM_D51, type code %A, sha256 e44f811ba37703b5…

62: PHASE CORUNDUM_D51:I %A 2 2 3 !
63: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-23Jia.tdb: CORUNDUM_D51, type code %A, sha256 16bc7d5f6d3971df…

59: PHASE CORUNDUM_D51:I %A 2 2 3 !
60: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-91Sun-LB.tdb: CORUNDUM_D51, type code %A, sha256 0670fd1794f0d2b7…

79: PHASE CORUNDUM_D51:I %A 2 2 3 !
80: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-91Sun-orig.tdb: CORUNDUM_D51, type code %A, sha256 214f51010594d665…

57: PHASE CORUNDUM_D51:I %A 2 2 3 !
58: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-93Tay.tdb: CORUNDUM_D51, type code %A, sha256 b5fe5c3fdd6ae4b4…

57: PHASE CORUNDUM_D51:I %A 2 2 3 !
58: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-95Kow.tdb: CORUNDUM_D51, type code %A, sha256 4b25481824b6c677…

60: PHASE CORUNDUM_D51:I %A 2 2 3 !
61: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

FeO-96Sel.tdb: CORUNDUM_D51, type code %A, sha256 35ab77bc661f3ab6…

61: PHASE CORUNDUM_D51:I %A 2 2 3 !
62: CONST CORUNDUM_D51:I : FE+3 : O-2 : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

FCC_A1 (Fe–O)

Id: phase:fe-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): 838.66–1802.44 K, x(O) 0–0.0001
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:fcc-a1
tdb: tdb:FeO-02Luo.tdb:FCC_A1, tdb:FeO-09Pov.tdb:FCC_A1, tdb:FeO-23Jia.tdb:FCC_A1, tdb:FeO-91Sun-LB.tdb:FCC_A1, tdb:FeO-91Sun-orig.tdb:FCC_A1, tdb:FeO-93Tay.tdb:FCC_A1, tdb:FeO-95Kow.tdb:FCC_A1, tdb:FeO-96Sel.tdb:FCC_A1

TDB models of FCC_A1 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: FCC_A1, type code %A, sha256 444e225f4fad778c…

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

FeO-09Pov.tdb: FCC_A1, type code %A, sha256 e44f811ba37703b5…

46: PHASE FCC_A1 %A 2 1 1 !
47: CONST FCC_A1 : FE : O VA% : !

FeO-23Jia.tdb: FCC_A1, type code %A, sha256 16bc7d5f6d3971df…

43: PHASE FCC_A1 %A 2 1 1 !
44: CONST FCC_A1 : FE : O VA% : !

FeO-91Sun-LB.tdb: FCC_A1, type code %A, sha256 0670fd1794f0d2b7…

63: PHASE FCC_A1 %A 2 1 1 !
64: CONST FCC_A1 : FE : O VA% : !

FeO-91Sun-orig.tdb: FCC_A1, type code %A, sha256 214f51010594d665…

41: PHASE FCC_A1 %A 2 1 1 !
42: CONST FCC_A1 : FE O : VA : !

FeO-93Tay.tdb: FCC_A1, type code %A, sha256 b5fe5c3fdd6ae4b4…

41: PHASE FCC_A1 %A 2 1 1 !
42: CONST FCC_A1 : FE O : VA : !

FeO-95Kow.tdb: FCC_A1, type code %A, sha256 4b25481824b6c677…

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

FeO-96Sel.tdb: FCC_A1, type code %A, sha256 35ab77bc661f3ab6…

45: PHASE FCC_A1 %A 2 1 1 !
46: CONST FCC_A1 : FE O : VA : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

GAS (Fe–O)

Id: phase:fe-o:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 1555.46–2500 K, x(O) 0.99965–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:gas
tdb: tdb:FeO-02Luo.tdb:GAS, tdb:FeO-09Pov.tdb:GAS, tdb:FeO-23Jia.tdb:GAS, tdb:FeO-91Sun-LB.tdb:GAS, tdb:FeO-91Sun-orig.tdb:GAS, tdb:FeO-93Tay.tdb:GAS, tdb:FeO-95Kow.tdb:GAS, tdb:FeO-96Sel.tdb:GAS

TDB models of GAS (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: GAS, type code %, sha256 444e225f4fad778c…

75: PHASE GAS:G % 1 1 !
76: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-09Pov.tdb: GAS, type code %, sha256 e44f811ba37703b5…

77: PHASE GAS:G % 1 1 !
78: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-23Jia.tdb: GAS, type code %, sha256 16bc7d5f6d3971df…

74: PHASE GAS:G % 1 1 !
75: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-91Sun-LB.tdb: GAS, type code %, sha256 0670fd1794f0d2b7…

94: PHASE GAS:G % 1 1 !
95: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-91Sun-orig.tdb: GAS, type code %, sha256 214f51010594d665…

72: PHASE GAS:G % 1 1 !
73: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-93Tay.tdb: GAS, type code %, sha256 b5fe5c3fdd6ae4b4…

72: PHASE GAS:G % 1 1 !
73: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-95Kow.tdb: GAS, type code %, sha256 4b25481824b6c677…

75: PHASE GAS:G % 1 1 !
76: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

FeO-96Sel.tdb: GAS, type code %, sha256 35ab77bc661f3ab6…

76: PHASE GAS:G % 1 1 !
77: CONST GAS:G : FE FE2 FEO FEO2 O O2% O3 : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

SPINEL_H11 (Fe–O)

Id: phase:fe-o:h11-spinel; status assigned
Structure: Al2MgO4 · H1_1 · cF56 · Fd-3m (227); type st:h1-1-al2mgo4-cf56; 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:SPINEL); structure as stated in the SGTE crystallographic table for this phase name and system
Caveat: partitioned order/disorder model in FeO-02Luo.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-09Pov.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-23Jia.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-91Sun-LB.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-91Sun-orig.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-93Tay.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-95Kow.tdb also describes the disordered state
Caveat: partitioned order/disorder model in FeO-96Sel.tdb also describes the disordered state
Stability: stable in 2 of 2 calculated diagram(s): 300–1869.74 K, x(O) 0.57089–0.57994
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:h11-spinel
tdb: tdb:FeO-02Luo.tdb:SPINEL_H11, tdb:FeO-09Pov.tdb:SPINEL_H11, tdb:FeO-23Jia.tdb:SPINEL_H11, tdb:FeO-91Sun-LB.tdb:SPINEL_H11, tdb:FeO-91Sun-orig.tdb:SPINEL_H11, tdb:FeO-93Tay.tdb:SPINEL_H11, tdb:FeO-95Kow.tdb:SPINEL_H11, tdb:FeO-96Sel.tdb:SPINEL_H11

TDB models of SPINEL_H11 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: SPINEL_H11, type code %A, sha256 444e225f4fad778c…

72: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
73: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-09Pov.tdb: SPINEL_H11, type code %A, sha256 e44f811ba37703b5…

74: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
75: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-23Jia.tdb: SPINEL_H11, type code %A, sha256 16bc7d5f6d3971df…

71: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
72: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-91Sun-LB.tdb: SPINEL_H11, type code %A, sha256 0670fd1794f0d2b7…

91: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
92: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-91Sun-orig.tdb: SPINEL_H11, type code %A, sha256 214f51010594d665…

69: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
70: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-93Tay.tdb: SPINEL_H11, type code %A, sha256 b5fe5c3fdd6ae4b4…

69: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
70: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-95Kow.tdb: SPINEL_H11, type code %A, sha256 4b25481824b6c677…

72: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
73: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

FeO-96Sel.tdb: SPINEL_H11, type code %A, sha256 35ab77bc661f3ab6…

73: PHASE SPINEL_H11:I %A 4 1 2 2 4 !
74: CONST SPINEL_H11:I : FE+2% FE+3 : FE+2 FE+3% VA : FE+2 VA% : O-2 : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

HCP_A3 (Fe–O)

Id: phase:fe-o:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stoichiometry: Fe 1.0000
Stability: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:hcp-a3
tdb: tdb:FeO-02Luo.tdb:HCP_A3, tdb:FeO-09Pov.tdb:HCP_A3, tdb:FeO-23Jia.tdb:HCP_A3, tdb:FeO-91Sun-LB.tdb:HCP_A3, tdb:FeO-91Sun-orig.tdb:HCP_A3, tdb:FeO-93Tay.tdb:HCP_A3, tdb:FeO-95Kow.tdb:HCP_A3, tdb:FeO-96Sel.tdb:HCP_A3

TDB models of HCP_A3 (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: HCP_A3, type code %A, sha256 444e225f4fad778c…

54: PHASE HCP_A3 %A 2 1 0.5 !
55: CONST HCP_A3 : FE : VA : !

FeO-09Pov.tdb: HCP_A3, type code %A, sha256 e44f811ba37703b5…

56: PHASE HCP_A3 %A 2 1 0.5 !
57: CONST HCP_A3 : FE : VA : !

FeO-23Jia.tdb: HCP_A3, type code %A, sha256 16bc7d5f6d3971df…

53: PHASE HCP_A3 %A 2 1 0.5 !
54: CONST HCP_A3 : FE : VA : !

FeO-91Sun-LB.tdb: HCP_A3, type code %A, sha256 0670fd1794f0d2b7…

73: PHASE HCP_A3 %A 2 1 0.5 !
74: CONST HCP_A3 : FE : VA : !

FeO-91Sun-orig.tdb: HCP_A3, type code %A, sha256 214f51010594d665…

51: PHASE HCP_A3 %A 2 1 0.5 !
52: CONST HCP_A3 : FE : VA : !

FeO-93Tay.tdb: HCP_A3, type code %A, sha256 b5fe5c3fdd6ae4b4…

51: PHASE HCP_A3 %A 2 1 0.5 !
52: CONST HCP_A3 : FE : VA : !

FeO-95Kow.tdb: HCP_A3, type code %A, sha256 4b25481824b6c677…

54: PHASE HCP_A3 %A 2 1 0.5 !
55: CONST HCP_A3 : FE : VA : !

FeO-96Sel.tdb: HCP_A3, type code %A, sha256 35ab77bc661f3ab6…

55: PHASE HCP_A3 %A 2 1 0.5 !
56: CONST HCP_A3 : FE : VA : !

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

ION (Fe–O)

Id: phase:fe-o:ion; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1642.72–2500 K, x(O) 2e-05–0.58105
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:fe-o:ion
tdb: tdb:FeO-09Pov.tdb:ION, tdb:FeO-91Sun-LB.tdb:ION, tdb:FeO-91Sun-orig.tdb:ION, tdb:FeO-93Tay.tdb:ION, tdb:FeO-96Sel.tdb:ION

TDB models of ION (5): PHASE and CONSTITUENT statements as written

FeO-09Pov.tdb: ION, type code %, sha256 e44f811ba37703b5…

41: PHASE ION:Y % 2 1 1 !
42: CONST ION:Y : FE+2 FE+3 : O-2 VA : !

FeO-91Sun-LB.tdb: ION, type code %, sha256 0670fd1794f0d2b7…

55: PHASE ION:Y % 2 1 1 !
56: CONST ION:Y : FE+2 : O-2 VA FEO1.5% : !

FeO-91Sun-orig.tdb: ION, type code %, sha256 214f51010594d665…

36: PHASE ION:Y % 2 1 1 !
37: CONST ION:Y : FE+2 FE+3 : O-2 VA : !

FeO-93Tay.tdb: ION, type code %, sha256 b5fe5c3fdd6ae4b4…

36: PHASE ION:Y % 2 1 1 !
37: CONST ION:Y : FE+2 FE+3 : O-2 VA : !

FeO-96Sel.tdb: ION, type code %, sha256 35ab77bc661f3ab6…

40: PHASE ION:Y % 2 1 1 !
41: CONST ION:Y : FE+2 : O-2 VA FEO1.5 : !

Example references (4 of 4; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
assessment that models this phase

LIQUID (Fe–O)

Id: phase:fe-o:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1642.22–2500 K, x(O) 2e-05–0.58105
Literature: 1 values (1 accepted) from 1 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:fe-o:liquid
paper: paper:10.1007/bf02645709:liquid
tdb: tdb:FeO-02Luo.tdb:LIQUID, tdb:FeO-23Jia.tdb:LIQUID, tdb:FeO-91Sun-LB.tdb:LIQUID, tdb:FeO-95Kow.tdb:LIQUID

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

FeO-02Luo.tdb: LIQUID, type code %, sha256 444e225f4fad778c…

39: PHASE LIQUID:L % 1 1 !
40: CONST LIQUID:L : FE FEO FEO1.5 : !

FeO-23Jia.tdb: LIQUID, type code %, sha256 16bc7d5f6d3971df…

38: PHASE LIQUID:L % 1 1 !
39: CONST LIQUID:L : FE FEO FEO1.5 : !

FeO-91Sun-LB.tdb: LIQUID, type code %, sha256 0670fd1794f0d2b7…

58: PHASE LIQUID:L % 1 1 !
59: CONST LIQUID:L : FE FEO FEO1.5 : !

FeO-95Kow.tdb: LIQUID, type code %, sha256 4b25481824b6c677…

39: PHASE LIQUID:L % 1 1 !
40: CONST LIQUID:L : FE FEO FEO1.5 : !

Example references (3 of 3; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase

O2GAS (Fe–O)

Id: phase:fe-o:o2gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 2 calculated diagram(s): 300–445 K, x(O) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (9): corpus: corpus:phase:fe-o:o2gas
tdb: tdb:FeO-02Luo.tdb:O2GAS, tdb:FeO-09Pov.tdb:O2GAS, tdb:FeO-23Jia.tdb:O2GAS, tdb:FeO-91Sun-LB.tdb:O2GAS, tdb:FeO-91Sun-orig.tdb:O2GAS, tdb:FeO-93Tay.tdb:O2GAS, tdb:FeO-95Kow.tdb:O2GAS, tdb:FeO-96Sel.tdb:O2GAS

TDB models of O2GAS (8): PHASE and CONSTITUENT statements as written

FeO-02Luo.tdb: O2GAS, type code %, sha256 444e225f4fad778c…

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

FeO-09Pov.tdb: O2GAS, type code %, sha256 e44f811ba37703b5…

80: PHASE O2GAS % 1 1 !
81: CONST O2GAS : O2 : !

FeO-23Jia.tdb: O2GAS, type code %, sha256 16bc7d5f6d3971df…

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

FeO-91Sun-LB.tdb: O2GAS, type code %, sha256 0670fd1794f0d2b7…

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

FeO-91Sun-orig.tdb: O2GAS, type code %, sha256 214f51010594d665…

75: PHASE O2GAS % 1 1 !
76: CONST O2GAS : O2 : !

FeO-93Tay.tdb: O2GAS, type code %, sha256 b5fe5c3fdd6ae4b4…

75: PHASE O2GAS % 1 1 !
76: CONST O2GAS : O2 : !

FeO-95Kow.tdb: O2GAS, type code %, sha256 4b25481824b6c677…

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

FeO-96Sel.tdb: O2GAS, type code %, sha256 35ab77bc661f3ab6…

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

Example references (6 of 6; assessments first):

doi:10.1007/BF02645709 B. Sundman, J. Phase Equilib., 12, 127-40(1991).
assessment that models this phase
doi:10.1007/s11669-009-9501-6 E. Povoden-Karadeniz, A. N. Grundy, M. Chen, T. Ivas, L. J. Gauckler, Thermodynamic Assessment of the La-Fe-O System, J. Phase Equilib. Diffus. 30, 351-366 (2009).
assessment that models this phase
doi:10.1016/0364-5916(95)00024-9 M. Kowalski, P.J. Spencer, Calphad, 19, 229-43(1995).
assessment that models this phase
doi:10.1016/j.jnucmat.2022.154180 Yueshan Jiang, Yanlin He, Weisen Zheng, Jianlei Zhang, Dekui Zhang, Xiaogang Lu, Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database, Journal of Nuclear Materials 574, 154180 (2023).
assessment that models this phase
doi:10.1016/S0364-5916(96)00039-9 M. Selleby, B. Sundman, Calphad, 20, 381-92(1996).
assessment that models this phase
doi:10.1515/ijmr-1993-840511 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 84, 335-45(1993).
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}
}