Si2O5

Si2O5 is a metastable, wide-band-gap insulating oxide of silicon that exhibits significant structural diversity.

OSi
Crystal structure of Si2O5 (orthorhombic, Ima2 (No. 46))
Ground-state structure · Materials Project
Overview

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.

At a glance

Key Properties

Cross-validated computational properties for Si2O5, aggregated across 4 databases.

Band Gap

3.05 eV
Range across DFT structures

Energy Above Hull

0.578 eV/atom
Best (lowest) across sources

Stability

Above hull
2 DFT sources

Structures

55
4 databases, 7 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for Si2O5, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
Ima2 (No. 46)orthorhombic3.050.5779-7.3122.33
No. 0unknown0.42
No. 0unknown0.41
No. 0unknown0.42
No. 0unknown0.43
No. 0unknown0.43
No. 0unknown0.43
No. 0unknown0.43
No. 0unknown0.43
No. 0unknown0.67
No. 0unknown0.68
No. 0unknown0.41
Uses

Applications

Where Si2O5 is used.

Fundamental materials science researchHigh-pressure phase studiesTheoretical modeling of silicon-oxygen frameworks
Reference

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.

More questions
What is Si2O5 used for?
Si2O5 is used in fundamental materials science research, high-pressure phase studies, and theoretical modeling of silicon-oxygen frameworks.
What is the band gap of Si2O5?
Si2O5 has a DFT-computed band gap of 3.05 eV across 55 reported structures.
Is Si2O5 a metal, semiconductor, or insulator?
With a wide band gap up to 3.05 eV it is an insulator / wide-band-gap material.
Is Si2O5 thermodynamically stable?
Si2O5 has a lowest energy above hull of 0.578 eV/atom (above hull).
What is the crystal structure of Si2O5?
The lowest-energy reported polymorph of Si2O5 is orthorhombic symmetry, space group Ima2 (No. 46).
What is the density of Si2O5?
The computed density of the ground-state structure of Si2O5 is 2.33 g/cm³.
How many polymorphs of Si2O5 are known?
55 structures of Si2O5 are reported across 4 databases, spanning 7 distinct space groups.
What elements does Si2O5 contain?
Si2O5 contains O and Si (2 elements).
Where does the data for Si2O5 come from?
Si2O5 data is cross-referenced from materials_project, cod.
Comparison

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
  • materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
  • cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).

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