Si2O5
Si2O5 is a metastable, wide-band-gap insulating oxide of silicon that exhibits significant structural diversity.
About Si2O5
Si2O5 is a silicon-oxygen compound characterized by its insulating electronic nature. As a wide-band-gap material, it represents a complex arrangement of silicon and oxygen atoms that has been the subject of extensive structural investigation across multiple databases. Its presence in numerous reported configurations highlights the structural diversity inherent in silicon-based oxides. Because it resides above the thermodynamic hull, Si2O5 is considered a metastable phase, suggesting that its formation and persistence are highly dependent on specific synthesis conditions. This metastability makes it an intriguing subject for researchers studying the boundaries of silicon oxide stability and the potential for novel structural motifs in high-pressure or non-equilibrium environments.
Key Properties
Cross-validated computational properties for Si2O5, aggregated across 3 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 Si2O5. 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 Si2O5, 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. |
|---|---|---|---|---|---|
| — | — | 3.32 | 0.2011 | -2.433 | — |
| Ima2 (No. 46) | orthorhombic | 3.23 | 0.3061 | -2.182 | — |
| — | — | 1.99 | 0.3392 | -2.295 | — |
| — | — | 1.87 | 0.3396 | -2.295 | — |
| Ima2 (No. 46) | orthorhombic | 3.05 | 0.5779 | -7.312 | 2.33 |
| — | — | 0.00 | 1.9366 | -0.698 | — |
| P2/m (No. 10) | monoclinic | — | — | — | 3.37 |
| P1 (No. 1) | triclinic | — | — | — | 3.03 |
| P-1 (No. 2) | triclinic | — | — | — | 3.43 |
| P-1 (No. 2) | triclinic | — | — | — | 5.08 |
| P-1 (No. 2) | triclinic | — | — | — | 3.93 |
| C2 (No. 5) | monoclinic | — | — | — | 3.61 |
Applications
Where Si2O5 is used.
Frequently Asked Questions
Common questions about Si2O5, answered from cross-validated data.
What is Si2O5?
Si2O5 is a metastable, wide-band-gap insulating oxide of silicon that exhibits significant structural diversity.
What is Si2O5 used for?
What is the band gap of Si2O5?
Is Si2O5 a metal, semiconductor, or insulator?
Is Si2O5 thermodynamically stable?
What is the crystal structure of Si2O5?
How many polymorphs of Si2O5 are known?
What elements does Si2O5 contain?
Where does the data for Si2O5 come from?
How It Compares
As a unique silicon oxide phase, Si2O5 occupies a distinct position within the landscape of silicon-oxygen materials, serving as a case study for metastable structural arrangements that deviate from the more common, thermodynamically favored silica polymorphs.
Data sources & attribution
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
Analyze Si2O5 in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →