NpSi
NpSi is a metastable metallic compound formed from neptunium and silicon that is studied for its unique structural properties in the context of advanced materials research.
About NpSi
NpSi is a metallic intermetallic compound composed of neptunium and silicon. As a member of the silicon anode materials class, it represents a specialized area of study for researchers investigating actinide-based alloys in advanced electrochemical systems.
Due to its metastable nature, this compound is of significant interest for fundamental materials science research. Its metallic electronic character distinguishes it from many traditional semiconductor-based silicides, making it a unique subject for exploring electron transport and structural stability in complex actinide systems.
Key Properties
Cross-validated computational properties for NpSi, aggregated across 6 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 NpSi. 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 NpSi, 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. |
|---|---|---|---|---|---|
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.0344 | -46.291 | 10.66 |
| — | — | 0.00 | 0.0382 | -0.155 | — |
| — | — | 0.00 | 0.0663 | -0.126 | — |
| — | — | 0.00 | 0.0954 | -0.097 | — |
| — | — | 0.00 | 0.1647 | -0.028 | — |
| — | — | 0.00 | 0.1892 | -0.003 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.2430 | -0.050 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.2430 | -0.050 | — |
| — | — | 0.00 | 0.2569 | 0.064 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.2807 | -46.045 | 13.12 |
| — | — | 0.00 | 0.3119 | 0.119 | — |
| — | — | 0.00 | 0.4487 | 0.256 | — |
Applications
Where NpSi is used.
Frequently Asked Questions
Common questions about NpSi, answered from cross-validated data.
What is NpSi?
NpSi is a metastable metallic compound formed from neptunium and silicon that is studied for its unique structural properties in the context of advanced materials research.
What is NpSi used for?
What is the band gap of NpSi?
Is NpSi a metal, semiconductor, or insulator?
Is NpSi thermodynamically stable?
What is the crystal structure of NpSi?
How many polymorphs of NpSi are known?
What elements does NpSi contain?
Where does the data for NpSi come from?
How It Compares
Within the silicon anode materials class.
Within the diverse family of silicon-based materials, NpSi occupies a niche position compared to more common silicides like Mg2Si or MoSi2. While materials such as Si or FeSi are frequently utilized for their well-understood semiconducting or metallic properties, NpSi is distinguished by the inclusion of heavy actinide elements, which introduces unique structural complexities not found in lighter transition metal or alkaline earth silicides.
Related Compounds
Other Silicon Anode Materials in the database.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
Analyze NpSi in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →