NpO
NpO is a metallic neptunium oxide that serves as a complex subject for research into actinide material stability and electronic behavior.
About NpO
NpO is a binary neptunium oxide characterized by its metallic electronic nature. As a compound containing an actinide element, it represents an intriguing subject for fundamental studies in heavy-element chemistry and solid-state physics. Due to its complex electronic structure, it remains a significant focus for researchers investigating the behavior of f-electron systems.
This material is noted for its structural diversity, with numerous reported configurations across various databases. While it is currently understood to be thermodynamically unstable relative to other phases, its existence in multiple structural forms provides valuable insights into the bonding and phase stability of actinide-based materials.
Key Properties
Cross-validated computational properties for NpO, 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.
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.
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.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of NpO. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for NpO, 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 | 0.1566 | -11.492 | 14.66 |
| Pmmn (No. 59) | Orthorhombic | — | — | — | 7.53 |
| R-3m (No. 166) | Trigonal | — | — | — | 11.74 |
| P-3m1 (No. 164) | Trigonal | — | — | — | 9.78 |
| C2/m (No. 12) | Monoclinic | — | — | — | 13.69 |
| R-3m (No. 166) | Trigonal | — | — | — | 11.70 |
| Fm-3m (No. 225) | — | — | — | — | — |
| Fm-3m (No. 225) | Cubic | — | — | — | 14.66 |
| Fm-3m (No. 225) | Cubic | — | — | — | 14.04 |
| Fm-3m (No. 225) | Cubic | — | — | — | 14.37 |
| C2/m (No. 12) | Monoclinic | — | — | — | 10.62 |
| C2/m (No. 12) | Monoclinic | — | — | — | 15.57 |
Applications
Where NpO is used.
Frequently Asked Questions
Common questions about NpO, answered from cross-validated data.
What is NpO?
NpO is a metallic neptunium oxide that serves as a complex subject for research into actinide material stability and electronic behavior.
What is NpO used for?
What is the band gap of NpO?
Is NpO a metal, semiconductor, or insulator?
Is NpO thermodynamically stable?
What is the crystal structure of NpO?
What is the density of NpO?
How many polymorphs of NpO are known?
What elements does NpO contain?
Where does the data for NpO come from?
How It Compares
As a unique actinide binary, NpO serves as a critical reference point for understanding the metallic nature of neptunium oxides. It occupies a distinct space in the study of actinide compounds, where its structural complexity and electronic properties highlight the challenges of predicting phase stability in heavy-element systems.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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