Cr–O phases
11 phases (tier A 6, tier C 1, liquid 2, gas 2); 6 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 · Cr–O system page · Markdown · field reference
| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---|---|
| BCC_A2 phase:cr-o:bcc-a2 | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 3 of 3 calculated diagram(s): 300–2179.98 K, x(O) 0–0.00078 | 0 | 3 |
| CR2O3_D51 phase:cr-o:cr2o3-d51 | alpha-Al2O3 · D5_1 · hR10 · R-3c (167) | tier A: standard phase name | stable in 3 of 3 calculated diagram(s): 300–2583.7 K, x(O) 0.59163–0.6 | 0 | 3 |
| CR3O4_H11 phase:cr-o:cr3o4-h11 | Al2MgO4 · H1_1 · cF56 · Fd-3m (227) | tier A: standard phase name | stable in 2 of 2 calculated diagram(s): 1917.97–1973.2 K, x(O) 0.57143–0.57143 | 0 | 2 |
| CRO_B1 phase:cr-o:cro-b1 | NaCl · B1 · cF8 · Fm-3m (225) | tier A: standard phase name | not stable in 1 calculated diagram(s) | 0 | 1 |
| FCC_A1 phase:cr-o:fcc-a1 | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | not stable in 3 calculated diagram(s) | 0 | 3 |
| GAS phase:cr-o:gas | gas | gas | stable in 3 of 3 calculated diagram(s): 300.1–3913.79 K, x(O) 0–1 | 0 | 3 |
| SPINEL_H11 phase:cr-o:h11-spinel | Al2MgO4 · H1_1 · cF56 · Fd-3m (227) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | not stable in 1 calculated diagram(s) | 0 | 1 |
| HCP_A3 phase:cr-o:hcp-a3 | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | not stable in 3 calculated diagram(s) | 0 | 3 |
| ION phase:cr-o:ion | liquid | liquid | stable in 3 of 3 calculated diagram(s): 1911.97–3913.79 K, x(O) 0–0.6 | 0 | 3 |
| LIQUID phase:cr-o:liquid | liquid | liquid | not stable in 3 calculated diagram(s) | 2 | 3 |
| O2GAS phase:cr-o:o2gas | gas | gas | stable in 3 of 3 calculated diagram(s): 300–1115 K, x(O) 1–1 | 0 | 3 |
BCC_A2 (Cr–O)
- Id:
phase:cr-o:bcc-a2; statusassigned - Structure: W · A2 · cI2 · Im-3m (229); type
st:a2-w-ci2; tier A: standard phase name; confidence high - Stability: stable in 3 of 3 calculated diagram(s): 300–2179.98 K, x(O) 0–0.00078
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:bcc-a2
tdb: tdb:CrO-06Pov.tdb:BCC_A2, tdb:CrO-10Kje.tdb:BCC_A2, tdb:CrO-90Tay.tdb:BCC_A2
TDB models of BCC_A2 (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: BCC_A2, type code %B, sha256 91b2e0d80ba0b62e…
58: PHASE BCC_A2 %B 2 1 3 ! 59: CONST BCC_A2 : CR : O VA% : !
CrO-10Kje.tdb: BCC_A2, type code %B, sha256 ee031ab4eb31aac1…
50: PHASE BCC_A2 %B 2 1 3 ! 51: CONST BCC_A2 : CR : O VA : !
CrO-90Tay.tdb: BCC_A2, type code %B, sha256 d075f681078353be…
55: PHASE BCC_A2 %B 2 1 3 ! 56: CONST BCC_A2 : CR : O VA : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
CR2O3_D51 (Cr–O)
- Id:
phase:cr-o:cr2o3-d51; statusassigned - Structure: alpha-Al2O3 · D5_1 · hR10 · R-3c (167); type
st:d5-1-alpha-al2o3-hr10; tier A: standard phase name; confidence high - Stability: stable in 3 of 3 calculated diagram(s): 300–2583.7 K, x(O) 0.59163–0.6
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:cr2o3-d51
tdb: tdb:CrO-06Pov.tdb:CR2O3_D51, tdb:CrO-10Kje.tdb:CR2O3_D51, tdb:CrO-90Tay.tdb:CR2O3_D51
TDB models of CR2O3_D51 (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: CR2O3_D51, type code %, sha256 91b2e0d80ba0b62e…
78: PHASE CR2O3_D51:I % 3 2 1 3 ! 79: CONST CR2O3_D51:I : CR+2 CR+3% : CR+3 VA% : O-2 : !
CrO-10Kje.tdb: CR2O3_D51, type code %A, sha256 ee031ab4eb31aac1…
60: PHASE CR2O3_D51:I %A 3 2 1 3 ! 61: CONST CR2O3_D51:I : CR+2 CR+3% : CR+3 VA% : O-2 : !
CrO-90Tay.tdb: CR2O3_D51, type code %A, sha256 d075f681078353be…
65: PHASE CR2O3_D51:I %A 3 2 1 3 ! 66: CONST CR2O3_D51:I : CR+2 CR+3% : CR+3 VA% : O-2 : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
CR3O4_H11 (Cr–O)
- Id:
phase:cr-o:cr3o4-h11; statusassigned - Structure: Al2MgO4 · H1_1 · cF56 · Fd-3m (227); type
st:h1-1-al2mgo4-cf56; tier A: standard phase name; confidence high - Stability: stable in 2 of 2 calculated diagram(s): 1917.97–1973.2 K, x(O) 0.57143–0.57143
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (3): corpus: corpus:phase:cr-o:cr3o4-h11
tdb: tdb:CrO-06Pov.tdb:CR3O4_H11, tdb:CrO-90Tay.tdb:CR3O4_H11
TDB models of CR3O4_H11 (2): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: CR3O4_H11, type code %, sha256 91b2e0d80ba0b62e…
73: PHASE CR3O4_H11:I % 3 1 2 4 ! 74: CONST CR3O4_H11:I : CR+2 : CR+3 : O-2 : !
CrO-90Tay.tdb: CR3O4_H11, type code %, sha256 d075f681078353be…
70: PHASE CR3O4_H11:I % 3 2 1 4 ! 71: CONST CR3O4_H11:I : CR+3 : CR+2 : O-2 : !
Example references (2 of 2; assessments first):
- doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
CRO_B1 (Cr–O)
- Id:
phase:cr-o:cro-b1; statusassigned - Structure: NaCl · B1 · cF8 · Fm-3m (225); type
st:b1-nacl-cf8; tier A: standard phase name; confidence high - 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:cr-o:cro-b1
tdb: tdb:CrO-06Pov.tdb:CRO_B1
TDB models of CRO_B1 (1): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: CRO_B1, type code %, sha256 91b2e0d80ba0b62e…
68: PHASE CRO_B1:I % 2 1 1 ! 69: CONST CRO_B1:I : CR+2 : O-2 : !
Example references (1 of 1; assessments first):
- doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase
FCC_A1 (Cr–O)
- Id:
phase:cr-o:fcc-a1; statusassigned - Structure: Cu · A1 · cF4 · Fm-3m (225); type
st:a1-cu-cf4; tier A: standard phase name; confidence high - Stoichiometry: Cr 1.0000
- Stability: not stable in 3 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:fcc-a1
tdb: tdb:CrO-06Pov.tdb:FCC_A1, tdb:CrO-10Kje.tdb:FCC_A1, tdb:CrO-90Tay.tdb:FCC_A1
TDB models of FCC_A1 (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: FCC_A1, type code %A, sha256 91b2e0d80ba0b62e…
53: PHASE FCC_A1 %A 2 1 1 ! 54: CONST FCC_A1 : CR : VA : !
CrO-10Kje.tdb: FCC_A1, type code %A, sha256 ee031ab4eb31aac1…
45: PHASE FCC_A1 %A 2 1 1 ! 46: CONST FCC_A1 : CR : VA : !
CrO-90Tay.tdb: FCC_A1, type code %A, sha256 d075f681078353be…
50: PHASE FCC_A1 %A 2 1 1 ! 51: CONST FCC_A1 : CR : VA : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
GAS (Cr–O)
- Id:
phase:cr-o:gas; statusassigned - Structure: gas; type
st:gas; gas; confidence high - Stability: stable in 3 of 3 calculated diagram(s): 300.1–3913.79 K, x(O) 0–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:gas
tdb: tdb:CrO-06Pov.tdb:GAS, tdb:CrO-10Kje.tdb:GAS, tdb:CrO-90Tay.tdb:GAS
TDB models of GAS (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: GAS, type code %, sha256 91b2e0d80ba0b62e…
84: PHASE GAS:G % 1 1 ! 85: CONST GAS:G : CR CR2 CR2O CRO CR2O2 CR2O3 CRO2 CRO3 O O2 O3 : !
CrO-10Kje.tdb: GAS, type code %, sha256 ee031ab4eb31aac1…
73: PHASE GAS:G % 1 1 ! 74: CONST GAS:G : CR CR2 CR2O CRO CR2O2 CR2O3 CRO2 CRO3 O O2 O3 : !
CrO-90Tay.tdb: GAS, type code %, sha256 d075f681078353be…
76: PHASE GAS:G % 1 1 ! 77: CONST GAS:G : CR CR2 CR2O CRO CR2O2 CR2O3 CRO2 CRO3 O O2 O3 : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
SPINEL_H11 (Cr–O)
- Id:
phase:cr-o:h11-spinel; statusassigned - 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
- 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:cr-o:h11-spinel
tdb: tdb:CrO-10Kje.tdb:SPINEL_H11
TDB models of SPINEL_H11 (1): PHASE and CONSTITUENT statements as written
CrO-10Kje.tdb: SPINEL_H11, type code %A, sha256 ee031ab4eb31aac1…
67: PHASE SPINEL_H11:I %A 4 1 2 2 4 ! 68: CONST SPINEL_H11:I : CR+2 CR+3 : CR+3 VA : CR+2 VA : O-2 : !
Example references (1 of 1; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase
HCP_A3 (Cr–O)
- Id:
phase:cr-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: Cr 1.0000
- Stability: not stable in 3 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:hcp-a3
tdb: tdb:CrO-06Pov.tdb:HCP_A3, tdb:CrO-10Kje.tdb:HCP_A3, tdb:CrO-90Tay.tdb:HCP_A3
TDB models of HCP_A3 (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: HCP_A3, type code %A, sha256 91b2e0d80ba0b62e…
63: PHASE HCP_A3 %A 2 1 0.5 ! 64: CONST HCP_A3 : CR : VA : !
CrO-10Kje.tdb: HCP_A3, type code %A, sha256 ee031ab4eb31aac1…
55: PHASE HCP_A3 %A 2 1 0.5 ! 56: CONST HCP_A3 : CR : VA : !
CrO-90Tay.tdb: HCP_A3, type code %A, sha256 d075f681078353be…
60: PHASE HCP_A3 %A 2 1 0.5 ! 61: CONST HCP_A3 : CR : VA : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
ION (Cr–O)
- Id:
phase:cr-o:ion; statusassigned - Structure: liquid; type
st:liquid; liquid; confidence high - Stability: stable in 3 of 3 calculated diagram(s): 1911.97–3913.79 K, x(O) 0–0.6
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:ion
tdb: tdb:CrO-06Pov.tdb:ION, tdb:CrO-10Kje.tdb:ION, tdb:CrO-90Tay.tdb:ION
TDB models of ION (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: ION, type code %, sha256 91b2e0d80ba0b62e…
48: PHASE ION:Y % 2 1 1 ! 49: CONST ION:Y : CR+2 CR+3 : O-2 VA : !
CrO-10Kje.tdb: ION, type code %, sha256 ee031ab4eb31aac1…
40: PHASE ION:Y % 2 1 1 ! 41: CONST ION:Y : CR+2 : O-2 VA CRO1.5 : !
CrO-90Tay.tdb: ION, type code %, sha256 d075f681078353be…
45: PHASE ION:Y % 2 1 1 ! 46: CONST ION:Y : CR+3 : O-2 VA O : !
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
LIQUID (Cr–O)
- Id:
phase:cr-o:liquid; statusassigned - Structure: liquid; type
st:liquid; liquid; confidence high - Stoichiometry: Cr 1.0000
- Stability: not stable in 3 calculated diagram(s)
- Literature: 2 values (2 accepted) from 1 papers
- Interactive: phase registry entry
Names (5): corpus: corpus:phase:cr-o:liquid
paper: paper:10.1361/154770306x116289:liquid
tdb: tdb:CrO-06Pov.tdb:LIQUID, tdb:CrO-10Kje.tdb:LIQUID, tdb:CrO-90Tay.tdb:LIQUID
TDB models of LIQUID (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: LIQUID, type code %, sha256 91b2e0d80ba0b62e…
45: PHASE LIQUID:L % 1 1 ! 46: CONST LIQUID:L : CR : !
CrO-10Kje.tdb: LIQUID, type code %, sha256 ee031ab4eb31aac1…
37: PHASE LIQUID:L % 1 1 ! 38: CONST LIQUID:L : CR : !
CrO-90Tay.tdb: LIQUID, type code %, sha256 d075f681078353be…
42: PHASE LIQUID:L % 1 1 ! 43: CONST LIQUID:L : CR : !
Example references (3 of 3; assessments first):
- doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase; reports values for this phase - doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase
O2GAS (Cr–O)
- Id:
phase:cr-o:o2gas; statusassigned - Structure: gas; type
st:gas; gas; confidence high - Stability: stable in 3 of 3 calculated diagram(s): 300–1115 K, x(O) 1–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: phase registry entry
Names (4): corpus: corpus:phase:cr-o:o2gas
tdb: tdb:CrO-06Pov.tdb:O2GAS, tdb:CrO-10Kje.tdb:O2GAS, tdb:CrO-90Tay.tdb:O2GAS
TDB models of O2GAS (3): PHASE and CONSTITUENT statements as written
CrO-06Pov.tdb: O2GAS, type code %, sha256 91b2e0d80ba0b62e…
81: PHASE O2GAS % 1 1 ! 82: CONST O2GAS : O2 :!
CrO-10Kje.tdb: O2GAS, type code %, sha256 ee031ab4eb31aac1…
70: PHASE O2GAS % 1 1 ! 71: CONST O2GAS : O2 :!
CrO-90Tay.tdb: O2GAS, type code %, sha256 d075f681078353be…
73: PHASE O2GAS % 1 1 ! 74: CONST O2GAS : O2 :!
Example references (3 of 3; assessments first):
- doi:10.1016/j.jallcom.2010.04.252 Lina Kjellqvist, Malin Selleby, Thermodynamic assessment of the Cr–Mn–O system, Journal of Alloys and Compounds 507, 84-92 (2010).
assessment that models this phase - doi:10.1361/154770306X116289 E. Povoden, A.N. Grundy, L.J. Gauckler, J. Phase Equilib. Diffus., 27, 353-62(2006).
assessment that models this phase - doi:10.1515/ijmr-1990-810509 J.R. Taylor, A.T. Dinsdale, Z. Metallkd., 81, 354-66(1990).
assessment that models this phase