NbC
NbC has a DFT band gap of Metallic / not reported across 307 reported structures in 40 space groups; its lowest-energy polymorph is cubic (Fm-3m (No. 225)). Cross-validated across 4 computational databases.
At a glance
Key Properties
Cross-validated computational properties for NbC, 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.
Metallic / not reported
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.
0.030 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.
Metastable
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
307
4 databases, 40 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for NbC, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 0.00 | 0.0298 | -17.876 | 7.61 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.1457 | -17.761 | 7.62 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.1686 | -17.738 | 6.52 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.4102 | -17.496 | 7.24 |
| F-43m (No. 216) | cubic | 0.00 | 0.5930 | -17.313 | 6.07 |
| Pm-3m (No. 221) | cubic | 0.00 | 0.9589 | -16.947 | 7.88 |
| P3221 (No. 154) | Trigonal | — | — | — | 5.57 |
| P1 (No. 1) | Triclinic | — | — | — | 5.13 |
| P3221 (No. 154) | Trigonal | — | — | — | 7.07 |
| Cm (No. 8) | Monoclinic | — | — | — | 6.04 |
| Cm (No. 8) | Monoclinic | — | — | — | 5.71 |
| Cc (No. 9) | Monoclinic | — | — | — | 6.13 |
Reference
Frequently Asked Questions
Common questions about NbC, answered from cross-validated data.
What is the band gap of NbC?
NbC is computed to be metallic (no band gap) in the reported DFT structures.
More questions
Is NbC a metal, semiconductor, or insulator?
Computed band structures report no gap, so it is metallic.
Is NbC thermodynamically stable?
NbC has a lowest energy above hull of 0.030 eV/atom (metastable).
What is the crystal structure of NbC?
The lowest-energy reported polymorph of NbC is cubic symmetry, space group Fm-3m (No. 225).
What is the density of NbC?
The computed density of the ground-state structure of NbC is 7.61 g/cm³.
How many polymorphs of NbC are known?
307 structures of NbC are reported across 4 databases, spanning 40 distinct space groups.
What elements does NbC contain?
NbC contains C and Nb (2 elements).
Where does the data for NbC come from?
NbC data is cross-referenced from materials_project, mpaloe, cod.
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Related Compounds
Other Ultra-High-Temperature Ceramics in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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