Octaphenylhexacyclooctasiloxane
CAS 5256-79-1
Pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane, 1,3,5,7,9,11,13,15-octaphenyl-
EPA and Census publish no US supply data for this chemical.
US productionNot reported
Top sourceNo public record
This chemical is listed as active in US commerce, but no company reported it to EPA’s survey for 2019 or 2023. Sites may have made or imported less than the threshold amount, or none.
Why supply is unknownWhere It Comes From
EPA and Census publish no US supply data for this chemical.
Why It Matters
No EPA sector or FDA product records name a use for this chemical.
Vendor Pricing
$2.86/gAaron Chemicals LLC
CountryHong Kong
Pack$286.00 / 100 g
Purity98%
Vendors13 available
Prices reflect listed pack sizes. Small research packs run far above bulk rates.
12 more vendors
| Vendor | Country Supplier country. Where available, shows shipping origin. When the supplier ships from a different country than where they are registered, both are shown. Most suppliers show registration country only. | $/g | Pack | Purity |
|---|---|---|---|---|
| Angene Chemical | China → Hong Kong | $3.07 | 100 g | 98% |
| Combi-Blocks, Inc. | United States | $3.10 | 100 g | 98% |
| A2B Chem LLC | United States | $3.33 | 100 g | 98% |
| AA BLOCKS | United States | $3.52 | 100 g | 98% |
| AstaTech (2 weeks) | United States | $4.06 | 100 g | 95% |
| BLD Pharmatech Co., Limited | United States | $6.00 | 10 g | 98% |
| Ambeed, Inc. | United States | $6.00 | 10 g | 98% |
| BLD Pharmatech Ltd. | China | $10.00 | 1 g | 98% |
| Sigma-Aldrich (Rush Stock) | Germany | $11.04 | 25 g | — |
| Sigma-Aldrich | Germany | $11.04 | 25 g | — |
| Angene International Limited | United States | $19.64 | 25 g | 98% |
| Angene | China → Hong Kong | $4266.67 | 30 mg | 98% |
Chemical Identity
CAS5256-79-1
PubChem CIDNot recorded
DTXSIDDTXSID00893550
FormulaC48H40O12Si8
Mol. Weight1033.516 g/mol
SMILESO1[Si]2(O[Si]3(O[Si]4(O[Si]1(O[Si]1(O[Si](O2)(O[Si](O3)(O[Si](O4)(O1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1)C1=CC=CC=C1
Data Sources
- EPA TSCA InventoryRetrieved 2026-10-04
Brief citations
Octaphenylhexacyclooctasiloxane (CAS 5256-79-1) https://chemicalindependence.com/chemical/5256-79-1/ EPA TSCA Inventory: CAS 5256-79-1. Retrieved 2026-10-04. https://www.epa.gov/tsca-inventory