Na2S2O3
sodium thiosulfate · hypo, sodium hyposulfite
Sodium thiosulfate is a widely used insulating chemical compound known for its role as a reducing agent in photography and water treatment.
About sodium thiosulfate
Sodium thiosulfate is a wide-band-gap insulating compound that plays a significant role in various chemical processes. Its structural complexity is highlighted by multiple reported configurations across major material databases, reflecting its utility in diverse environments.
Despite being positioned above the thermodynamic hull, this compound remains a critical reagent in analytical chemistry and industrial manufacturing. Its ability to act as a reducing agent makes it indispensable for neutralizing oxidizing agents in practical applications.
Key Properties
Cross-validated computational properties for sodium thiosulfate, 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.
Reported Structures
Lowest-energy structures reported for Na2S2O3, 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. |
|---|---|---|---|---|---|
| P21/c (No. 14) | monoclinic | 4.08 | 0.1332 | -5.418 | 2.28 |
| Pna21 (No. 33) | orthorhombic | 4.00 | 0.1348 | -5.417 | 2.24 |
| P1 (No. 1) | triclinic | 0.00 | 1.0858 | -4.466 | 1.55 |
| P21/c (No. 14) | — | — | — | — | — |
| P21/c (No. 14) | Monoclinic | — | — | — | 2.28 |
| P21/c (No. 14) | Monoclinic | — | — | — | 2.40 |
| P21/c (No. 14) | Monoclinic | — | — | — | 2.32 |
Applications
Where sodium thiosulfate is used.
Frequently Asked Questions
Common questions about sodium thiosulfate, answered from cross-validated data.
What is Na2S2O3?
Sodium thiosulfate is a widely used insulating chemical compound known for its role as a reducing agent in photography and water treatment.
What is Na2S2O3 used for?
What is the band gap of Na2S2O3?
Is Na2S2O3 a metal, semiconductor, or insulator?
Is Na2S2O3 thermodynamically stable?
What is the crystal structure of Na2S2O3?
What is the density of Na2S2O3?
How many polymorphs of Na2S2O3 are known?
What elements does Na2S2O3 contain?
Where does the data for Na2S2O3 come from?
How It Compares
As a standalone compound in this context, sodium thiosulfate serves as a foundational example of sulfur-based oxoanion chemistry, demonstrating how insulating materials can be effectively utilized for their chemical reactivity rather than purely electronic properties.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
- mpaloe — Data from mpaloe.
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