Nb4O8
Nb4O8 has a DFT band gap of 0.04–0.43 eV across 53 reported structures in 21 space groups; its lowest-energy polymorph is tetragonal (I41/a (No. 88)). Cross-validated across 4 computational databases.
At a glance
Key Properties
Cross-validated computational properties for Nb4O8, aggregated across 4 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
0.04–0.43 eV
Range across DFT structures
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
0.000 eV/atom
Best (lowest) across sources
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
53
4 databases, 21 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Nb4O8, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| I41/a (No. 88) | tetragonal | 0.28 | 0.0000 | -9.563 | 5.75 |
| I41/a (No. 88) | tetragonal | 0.43 | 0.0024 | -9.561 | 5.73 |
| P42/mnm (No. 136) | tetragonal | 0.00 | 0.0475 | -9.516 | 5.72 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.0526 | -9.511 | 4.98 |
| Pbca (No. 61) | orthorhombic | 0.00 | 0.0721 | -9.491 | 6.15 |
| I41/amd (No. 141) | tetragonal | 0.00 | 0.0800 | -9.483 | 5.70 |
| P1 (No. 1) | triclinic | 0.04 | 0.2079 | -9.356 | 4.56 |
| P1 (No. 1) | triclinic | 0.00 | 0.2591 | -9.304 | 5.19 |
| P1 (No. 1) | triclinic | 0.05 | 0.2597 | -9.304 | 4.80 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.2834 | -9.280 | 5.22 |
| I41/a (No. 88) | tetragonal | 0.19 | 0.3109 | -9.252 | 3.97 |
| C2/m (No. 12) | — | — | — | — | — |
Reference
Frequently Asked Questions
Common questions about Nb4O8, answered from cross-validated data.
What is the band gap of Nb4O8?
Nb4O8 has a DFT-computed band gap of 0.04–0.43 eV across 53 reported structures.
More questions
Is Nb4O8 a metal, semiconductor, or insulator?
With a band gap up to 0.43 eV it is a semiconductor.
Is Nb4O8 thermodynamically stable?
Yes — Nb4O8 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of Nb4O8?
The lowest-energy reported polymorph of Nb4O8 is tetragonal symmetry, space group I41/a (No. 88).
What is the density of Nb4O8?
The computed density of the ground-state structure of Nb4O8 is 5.75 g/cm³.
How many polymorphs of Nb4O8 are known?
53 structures of Nb4O8 are reported across 4 databases, spanning 21 distinct space groups.
What elements does Nb4O8 contain?
Nb4O8 contains Nb and O (2 elements).
Where does the data for Nb4O8 come from?
Nb4O8 data is cross-referenced from materials_project, aflow, omat24, cod.
Explore
Related Compounds
Other Electrochromic and Refractory-Metal Oxides in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- aflow — Data from AFLOW. Cite: Curtarolo et al., Comp. Mater. Sci. 58, 218 (2012).
- omat24 — Data from OMat24 (Meta FAIR). Cite: Barroso-Luque et al., arXiv 2410.12771 (2024).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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