F–Nb phases

9 phases (tier A 4, tier B 1, tier C 1, liquid 2, gas 1); 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 · F–Nb system page · Markdown · field reference

Phases of the F–Nb system (9)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:f-nb:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2750 K, x(F) 0–0	0	1
FCC_A1 phase:f-nb:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
GAS phase:f-nb:gas	gas	gas	stable in 1 of 1 calculated diagram(s): 300–4000 K, x(F) 0.83333–1	0	1
HCP_A3 phase:f-nb:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
ION phase:f-nb:ion	liquid	liquid	stable in 1 of 1 calculated diagram(s): 351.91–4000 K, x(F) 0–0.83333	0	1
LIQUID phase:f-nb:liquid	liquid	liquid	not stable in 1 calculated diagram(s)	0	1
NBF3_D09 phase:f-nb:nbf3-d09	ReO3 alpha · D0_9 · cP4 · Pm-3m (221)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1608.13 K, x(F) 0.75–0.75	9	1
NBF4 phase:f-nb:nbf4	SnF4 · tI10 · I4/mmm (139)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–858.21 K, x(F) 0.8–0.8	9	1
NBF5 phase:f-nb:nbf5	MoF5 · mC48 · C2/m (12)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–351.91 K, x(F) 0.83333–0.83333	11	1

BCC_A2 (F–Nb)

Id: phase:f-nb:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stoichiometry: Nb 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–2750 K, x(F) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:f-nb:bcc-a2
tdb: tdb:NbF-18Cap.tdb:BCC_A2

TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: BCC_A2, type code %B, sha256 ce57e253cc4ca1be…

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

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

FCC_A1 (F–Nb)

Id: phase:f-nb:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stoichiometry: Nb 1.0000
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:f-nb:fcc-a1
tdb: tdb:NbF-18Cap.tdb:FCC_A1

TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: FCC_A1, type code %A, sha256 ce57e253cc4ca1be…

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

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

GAS (F–Nb)

Id: phase:f-nb:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–4000 K, x(F) 0.83333–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:f-nb:gas
tdb: tdb:NbF-18Cap.tdb:GAS

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

NbF-18Cap.tdb: GAS, type code %, sha256 ce57e253cc4ca1be…

82: PHASE GAS:G % 1 1 !
83: CONST GAS:G : NB NBF5 F F2 : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

HCP_A3 (F–Nb)

Id: phase:f-nb: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: Nb 1.0000
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:f-nb:hcp-a3
tdb: tdb:NbF-18Cap.tdb:HCP_A3

TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: HCP_A3, type code %A, sha256 ce57e253cc4ca1be…

64: PHASE HCP_A3 %A 2 1 0.5 !
65: CONST HCP_A3 : NB : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

ION (F–Nb)

Id: phase:f-nb:ion; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 351.91–4000 K, x(F) 0–0.83333
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:f-nb:ion
tdb: tdb:NbF-18Cap.tdb:ION

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

NbF-18Cap.tdb: ION, type code %, sha256 ce57e253cc4ca1be…

46: PHASE ION:Y % 2 1 1 !
47: CONST ION:Y : NB+5 : F-1 VA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

LIQUID (F–Nb)

Id: phase:f-nb:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stoichiometry: Nb 1.0000
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:f-nb:liquid
tdb: tdb:NbF-18Cap.tdb:LIQUID

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

NbF-18Cap.tdb: LIQUID, type code %, sha256 ce57e253cc4ca1be…

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

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase

NBF3_D09 (F–Nb)

Id: phase:f-nb:nbf3-d09; status assigned
Structure: ReO3 alpha · D0_9 · cP4 · Pm-3m (221); type st:d0-9-reo3-alpha-cp4; tier A: standard phase name; confidence high
Stoichiometry: F 0.7500, Nb 0.2500
Stability: stable in 1 of 1 calculated diagram(s): 300–1608.13 K, x(F) 0.75–0.75
Literature: 9 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:f-nb:nbf3-d09
paper: paper:10.1016/j.jfluchem.2018.01.011:NbF3 (cr), paper:10.1016/j.jfluchem.2018.01.011:NbF3(g)
tdb: tdb:NbF-18Cap.tdb:NBF3_D09

TDB models of NBF3_D09 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: NBF3_D09, type code %, sha256 ce57e253cc4ca1be…

69: PHASE NBF3_D09 % 2 1 3 !
70: CONST NBF3_D09 : NB : F : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase; reports values for this phase

NBF4 (F–Nb)

Id: phase:f-nb:nbf4; status assigned
Structure: SnF4 · tI10 · I4/mmm (139); type st:snf4-ti10; 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 (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: F 0.8000, Nb 0.2000
Stability: stable in 1 of 1 calculated diagram(s): 300–858.21 K, x(F) 0.8–0.8
Literature: 9 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:f-nb:nbf4
paper: paper:10.1016/j.jfluchem.2018.01.011:NbF4 (cr), paper:10.1016/j.jfluchem.2018.01.011:NbF4(g)
tdb: tdb:NbF-18Cap.tdb:NBF4

TDB models of NBF4 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: NBF4, type code %, sha256 ce57e253cc4ca1be…

74: PHASE NBF4 % 2 1 4 !
75: CONST NBF4 : NB : F : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase; reports values for this phase

NBF5 (F–Nb)

Id: phase:f-nb:nbf5; status assigned
Structure: MoF5 · mC48 · C2/m (12); type st:mof5-mc48; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: F 0.8333, Nb 0.1667
Stability: stable in 1 of 1 calculated diagram(s): 300–351.91 K, x(F) 0.83333–0.83333
Literature: 11 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:f-nb:nbf5
mp: mp:mp-aaaabbqt
oqmd: oqmd:oqmd-5080
paper: paper:10.1016/j.jfluchem.2018.01.011:NbF5 (cr), paper:10.1016/j.jfluchem.2018.01.011:NbF5 (liq), paper:10.1016/j.jfluchem.2018.01.011:NbF5(g)
tdb: tdb:NbF-18Cap.tdb:NBF5

TDB models of NBF5 (1): PHASE and CONSTITUENT statements as written

NbF-18Cap.tdb: NBF5, type code %, sha256 ce57e253cc4ca1be…

79: PHASE NBF5 % 2 1 5 !
80: CONST NBF5 : NB : F : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jfluchem.2018.01.011 E. Capelli, R.J.M. Konings, Thermodynamic assessment of the niobium-fluorine system by coupling density functional theory and CALPHAD approach, Journal of Fluorine Chemistry 208, 55-64 (2018).
assessment that models this phase; reports values for 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}
}