Gd–O phases
11 phases (tier A 3, tier C 5, liquid 1, gas 2); 7 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 · Gd–O system page · Markdown · field reference
| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---|---|
| B_R2O3 phase:gd-o:b-r2o3 | B-Sm2O3 · mC30 · C2/m (12) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | not stable in 2 calculated diagram(s) | 0 | 2 |
| BCC_A2 phase:gd-o:bcc-a2 | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 2 calculated diagram(s): 1586.12–2499.87 K, x(O) 0–0 | 0 | 2 |
| A_R2O3_D52 phase:gd-o:d52-a-r2o3 | A-La2O3 · D5_2 · hP5 · P-3m1 (164) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | not stable in 2 calculated diagram(s) | 0 | 2 |
| C_R2O3_D53 phase:gd-o:d53-c-r2o3 | Mn2O3 · D5_3 · cI80 · Ia-3 (206) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 2 of 2 calculated diagram(s): 300–535 K, x(O) 0.6–0.6 | 0 | 2 |
| FCC_A1 phase:gd-o:fcc-a1 | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | not stable in 2 calculated diagram(s) | 0 | 2 |
| GAS phase:gd-o:gas | gas | gas | stable in 2 of 2 calculated diagram(s): 2485–2500 K, x(O) 1–1 | 0 | 2 |
| H_R2O3 phase:gd-o:h-r2o3 | H-La2O3 · hP10 · P6_3/mmc (194) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 2 of 2 calculated diagram(s): 2485–2500 K, x(O) 0.6–0.6 | 0 | 2 |
| HCP_A3 phase:gd-o:hcp-a3 | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 300–325 K, x(O) 0–0 | 0 | 2 |
| ION phase:gd-o:ion | liquid | liquid | stable in 2 of 2 calculated diagram(s): 1586.12–2500 K, x(O) 0–0.56845 | 0 | 2 |
| O2GAS phase:gd-o:o2gas | gas | gas | stable in 2 of 2 calculated diagram(s): 300–535 K, x(O) 1–1 | 0 | 2 |
| X_R2O3 phase:gd-o:r2o3-x | Nd2O3 · cI26 · Im-3m (229) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | not stable in 2 calculated diagram(s) | 0 | 2 |
B_R2O3 (Gd–O)
- Id:
phase:gd-o:b-r2o3; statusassigned - Structure: B-Sm2O3 · mC30 · C2/m (12); type
st:b-sm2o3-mc30; 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 (name_has_descriptive_tokens:B,R2O3, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:b-r2o3
tdb: tdb:GdO-14McM.tdb:B_R2O3, tdb:GdO-23Nak.tdb:B_R2O3
TDB models of B_R2O3 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: B_R2O3, type code %, sha256 b72717c7ab25c852…
58: PHASE B_R2O3:I % 2 2 3 ! 59: CONST B_R2O3:I : GD+3 : O-2 : !
GdO-23Nak.tdb: B_R2O3, type code %, sha256 bd0ea93f229ea2a2…
56: PHASE B_R2O3:I % 2 2 3 ! 57: CONST B_R2O3:I : GD+3 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
BCC_A2 (Gd–O)
- Id:
phase:gd-o:bcc-a2; statusassigned - Structure: W · A2 · cI2 · Im-3m (229); type
st:a2-w-ci2; tier A: standard phase name; confidence high - Stoichiometry: Gd 1.0000
- Stability: stable in 1 of 2 calculated diagram(s): 1586.12–2499.87 K, x(O) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:bcc-a2
tdb: tdb:GdO-14McM.tdb:BCC_A2, tdb:GdO-23Nak.tdb:BCC_A2
TDB models of BCC_A2 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: BCC_A2, type code %B, sha256 b72717c7ab25c852…
43: PHASE BCC_A2 %B 2 1 3 ! 44: CONST BCC_A2 : GD : VA : !
GdO-23Nak.tdb: BCC_A2, type code %B, sha256 bd0ea93f229ea2a2…
41: PHASE BCC_A2 %B 2 1 3 ! 42: CONST BCC_A2 : GD : VA : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
A_R2O3_D52 (Gd–O)
- Id:
phase:gd-o:d52-a-r2o3; statusassigned - 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: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:d52-a-r2o3
tdb: tdb:GdO-14McM.tdb:A_R2O3_D52, tdb:GdO-23Nak.tdb:A_R2O3_D52
TDB models of A_R2O3_D52 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: A_R2O3_D52, type code %, sha256 b72717c7ab25c852…
53: PHASE A_R2O3_D52:I % 2 2 3 ! 54: CONST A_R2O3_D52:I : GD+3 : O-2 : !
GdO-23Nak.tdb: A_R2O3_D52, type code %, sha256 bd0ea93f229ea2a2…
51: PHASE A_R2O3_D52:I % 2 2 3 ! 52: CONST A_R2O3_D52:I : GD+3 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
C_R2O3_D53 (Gd–O)
- Id:
phase:gd-o:d53-c-r2o3; statusassigned - Structure: Mn2O3 · D5_3 · cI80 · Ia-3 (206); type
st:d5-3-mn2o3-ci80; 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:C,R2O3); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 2 of 2 calculated diagram(s): 300–535 K, x(O) 0.6–0.6
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:d53-c-r2o3
tdb: tdb:GdO-14McM.tdb:C_R2O3_D53, tdb:GdO-23Nak.tdb:C_R2O3_D53
TDB models of C_R2O3_D53 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: C_R2O3_D53, type code %, sha256 b72717c7ab25c852…
63: PHASE C_R2O3_D53:I % 2 2 3 ! 64: CONST C_R2O3_D53:I : GD+3 : O-2 : !
GdO-23Nak.tdb: C_R2O3_D53, type code %, sha256 bd0ea93f229ea2a2…
61: PHASE C_R2O3_D53:I % 2 2 3 ! 62: CONST C_R2O3_D53:I : GD+3 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
FCC_A1 (Gd–O)
- Id:
phase:gd-o:fcc-a1; statusassigned - Structure: Cu · A1 · cF4 · Fm-3m (225); type
st:a1-cu-cf4; tier A: standard phase name; confidence high - Stoichiometry: Gd 1.0000
- Stability: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:fcc-a1
tdb: tdb:GdO-14McM.tdb:FCC_A1, tdb:GdO-23Nak.tdb:FCC_A1
TDB models of FCC_A1 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: FCC_A1, type code %A, sha256 b72717c7ab25c852…
38: PHASE FCC_A1 %A 2 1 1 ! 39: CONST FCC_A1 : GD : VA : !
GdO-23Nak.tdb: FCC_A1, type code %A, sha256 bd0ea93f229ea2a2…
36: PHASE FCC_A1 %A 2 1 1 ! 37: CONST FCC_A1 : GD : VA : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
GAS (Gd–O)
- Id:
phase:gd-o:gas; statusassigned - Structure: gas; type
st:gas; gas; confidence high - Stability: stable in 2 of 2 calculated diagram(s): 2485–2500 K, x(O) 1–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:gas
tdb: tdb:GdO-14McM.tdb:GAS, tdb:GdO-23Nak.tdb:GAS
TDB models of GAS (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: GAS, type code %, sha256 b72717c7ab25c852…
76: PHASE GAS:G % 1 1 ! 77: CONST GAS:G : GD GDO O O2% O3 : !
GdO-23Nak.tdb: GAS, type code %, sha256 bd0ea93f229ea2a2…
74: PHASE GAS:G % 1 1 ! 75: CONST GAS:G : GD GDO O O2% O3 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
H_R2O3 (Gd–O)
- Id:
phase:gd-o:h-r2o3; statusassigned - Structure: H-La2O3 · hP10 · P6_3/mmc (194); type
st:h-la2o3-hp10; 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 (name_has_descriptive_tokens:H,R2O3, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: stable in 2 of 2 calculated diagram(s): 2485–2500 K, x(O) 0.6–0.6
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:h-r2o3
tdb: tdb:GdO-14McM.tdb:H_R2O3, tdb:GdO-23Nak.tdb:H_R2O3
TDB models of H_R2O3 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: H_R2O3, type code %, sha256 b72717c7ab25c852…
68: PHASE H_R2O3:I % 2 2 3 ! 69: CONST H_R2O3:I : GD+3 : O-2 : !
GdO-23Nak.tdb: H_R2O3, type code %, sha256 bd0ea93f229ea2a2…
66: PHASE H_R2O3:I % 2 2 3 ! 67: CONST H_R2O3:I : GD+3 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
HCP_A3 (Gd–O)
- Id:
phase:gd-o:hcp-a3; statusassigned - Structure: Mg · A3 · hP2 · P6_3/mmc (194); type
st:a3-mg-hp2; tier A: standard phase name; confidence high - Stoichiometry: Gd 1.0000
- Stability: stable in 2 of 2 calculated diagram(s): 300–325 K, x(O) 0–0
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:hcp-a3
tdb: tdb:GdO-14McM.tdb:HCP_A3, tdb:GdO-23Nak.tdb:HCP_A3
TDB models of HCP_A3 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: HCP_A3, type code %A, sha256 b72717c7ab25c852…
48: PHASE HCP_A3 %A 2 1 0.5 ! 49: CONST HCP_A3 : GD : VA : !
GdO-23Nak.tdb: HCP_A3, type code %A, sha256 bd0ea93f229ea2a2…
46: PHASE HCP_A3 %A 2 1 0.5 ! 47: CONST HCP_A3 : GD : VA : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
ION (Gd–O)
- Id:
phase:gd-o:ion; statusassigned - Structure: liquid; type
st:liquid; liquid; confidence high - Stability: stable in 2 of 2 calculated diagram(s): 1586.12–2500 K, x(O) 0–0.56845
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:ion
tdb: tdb:GdO-14McM.tdb:ION, tdb:GdO-23Nak.tdb:ION
TDB models of ION (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: ION, type code %, sha256 b72717c7ab25c852…
33: PHASE ION:Y % 2 1 1 ! 34: CONST ION:Y : GD+3 : O-2 VA : !
GdO-23Nak.tdb: ION, type code %, sha256 bd0ea93f229ea2a2…
31: PHASE ION:Y % 2 1 1 ! 32: CONST ION:Y : GD+3 : O-2 VA : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
O2GAS (Gd–O)
- Id:
phase:gd-o:o2gas; statusassigned - Structure: gas; type
st:gas; gas; confidence high - Stability: stable in 2 of 2 calculated diagram(s): 300–535 K, x(O) 1–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:o2gas
tdb: tdb:GdO-14McM.tdb:O2GAS, tdb:GdO-23Nak.tdb:O2GAS
TDB models of O2GAS (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: O2GAS, type code %, sha256 b72717c7ab25c852…
79: PHASE O2GAS % 1 1 ! 80: CONST O2GAS : O2 : !
GdO-23Nak.tdb: O2GAS, type code %, sha256 bd0ea93f229ea2a2…
77: PHASE O2GAS % 1 1 ! 78: CONST O2GAS : O2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase
X_R2O3 (Gd–O)
- Id:
phase:gd-o:r2o3-x; statusassigned - Structure: Nd2O3 · cI26 · Im-3m (229); type
st:nd2o3-ci26; 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 (name_has_descriptive_tokens:R2O3,X, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stability: not stable in 2 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:gd-o:r2o3-x
tdb: tdb:GdO-14McM.tdb:X_R2O3, tdb:GdO-23Nak.tdb:X_R2O3
TDB models of X_R2O3 (2): PHASE and CONSTITUENT statements as written
GdO-14McM.tdb: X_R2O3, type code %, sha256 b72717c7ab25c852…
73: PHASE X_R2O3:I % 2 2 3 ! 74: CONST X_R2O3:I : GD+3 : O-2 : !
GdO-23Nak.tdb: X_R2O3, type code %, sha256 bd0ea93f229ea2a2…
71: PHASE X_R2O3:I % 2 2 3 ! 72: CONST X_R2O3:I : GD+3 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1016/j.calphad.2023.102636 R. Nakazawa, A. Itoh, S. Yasui, M. Kurata, Y. Kobayashi, Calphad, 83, 102636(2023).
assessment that models this phase - doi:10.1016/j.jnucmat.2014.04.047 J.W. McMurray, D. Shin, B.W. Slone, T.M. Besmann, Thermodynamic reassessment of U–Gd–O system, Journal of Nuclear Materials 452, 397-406 (2014).
assessment that models this phase