Si
Silicon · Si
Silicon is a stable, semiconducting element widely utilized as a high-capacity anode material in advanced battery technologies.
About Silicon
Silicon is a foundational semiconducting material that serves as the primary building block for modern electronics and advanced energy storage systems. As a thermodynamically stable phase on the convex hull, it offers a robust structural framework that is essential for high-performance anode applications in lithium-ion batteries.
Its significance lies in its ability to host large amounts of charge, making it a critical focus for research into high-capacity energy storage. With an extensive range of reported structural variations across multiple databases, silicon remains one of the most thoroughly characterized and versatile materials in the semiconductor class.
Key Properties
Cross-validated computational properties for Silicon, aggregated across 5 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 Si. 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 Si, 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. |
|---|---|---|---|---|---|
| Fd-3m (No. 227) | cubic | 0.61 | 0.0000 | -8.774 | 2.31 |
| P63/mmc (No. 194) | hexagonal | 0.44 | 0.0136 | -8.760 | 2.32 |
| C2/m (No. 12) | monoclinic | 0.27 | 0.0822 | -8.692 | 2.23 |
| P63/mmc (No. 194) | hexagonal | 1.36 | 0.0844 | -8.689 | 2.01 |
| Pm-3n (No. 223) | cubic | 1.44 | 0.0918 | -8.682 | 2.03 |
| I-43m (No. 217) | cubic | 1.37 | 0.1075 | -8.666 | 2.11 |
| P6/mmm (No. 191) | hexagonal | 1.13 | 0.1105 | -8.663 | 2.01 |
| Cmcm (No. 63) | orthorhombic | 0.50 | 0.1105 | -8.663 | 2.15 |
| I4/mmm (No. 139) | tetragonal | 0.44 | 0.1166 | -8.657 | 2.19 |
| Pa-3 (No. 205) | cubic | 1.01 | 0.1212 | -8.653 | 1.97 |
| C2/c (No. 15) | monoclinic | 1.00 | 0.1289 | -8.645 | 2.04 |
| Cmcm (No. 63) | orthorhombic | 1.52 | 0.1291 | -8.645 | 2.01 |
Applications
Where Silicon is used.
Frequently Asked Questions
Common questions about Silicon, answered from cross-validated data.
What is Si?
Silicon is a stable, semiconducting element widely utilized as a high-capacity anode material in advanced battery technologies.
What is Si used for?
What is the band gap of Si?
Is Si a metal, semiconductor, or insulator?
Is Si thermodynamically stable?
What is the crystal structure of Si?
What is the density of Si?
How many polymorphs of Si are known?
What elements does Si contain?
Where does the data for Si come from?
How It Compares
Within the silicon anode materials class.
Within the class of silicon-based anode materials, pure silicon stands out as the elemental benchmark against which complex compounds like Mg2Si, MoSi2, and BaSi2 are measured. While its siblings often introduce metallic or intermetallic character to balance structural stability and conductivity, elemental silicon remains the primary reference point for maximizing theoretical capacity in electrochemical cells.
Related Compounds
Other Silicon Anode Materials in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
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