- ▸ Solvent extraction: Metal-ion extractant in hydrometallurgical separation
- ▸ Coordination chemistry: Coordinating ligand for metal complexes
- ▸ Nanomaterials: Coordinating solvent/ligand in nanocrystal and quantum-dot synthesis
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
Request SDS →Tri-n-octylphosphine oxide (CAS 78-50-2, C24H51OP) is a strongly coordinating trialkylphosphine oxide. It is used as a metal-ion extractant in solvent-extraction processes and as a coordinating ligand in coordination and nanocrystal chemistry.
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 201-121-3
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Solutions Using This Product
Process-solution guides on this site that specify this chemistry:
- Solvent Extraction (SX) Reagents for Hydrometallurgy (Oil, Gas & Mining)
Frequently Asked Questions
What is the use of trioctylphosphine oxide (TOPO)?
Tri-n-octylphosphine oxide (TOPO, CAS 78-50-2, C24H51OP) is a strongly coordinating trialkylphosphine oxide. It is used as a metal-ion extractant in hydrometallurgical solvent-extraction processes, as a coordinating ligand for metal complexes, and as a coordinating solvent/ligand in nanocrystal and quantum-dot synthesis. We supply it as a specialty additive in bulk.
Is TOPO the same as triphenylphosphine oxide (TPPO)?
No. TOPO is the tri-n-octyl (alkyl) phosphine oxide, C24H51OP (CAS 78-50-2), whereas TPPO is the triphenyl (aryl) analog. They differ in structure, solubility, and coordinating behavior and are not interchangeable; confirm CAS and identity on the CoA.
What is the solubility of trioctylphosphine oxide?
TOPO is a waxy solid that is soluble in many organic solvents and essentially insoluble in water, which suits its role in solvent extraction and as a coordinating solvent in nanocrystal synthesis. Lot-specific physical data is on the technical data sheet and SDS.
What is the CAS number and formula of TOPO?
Tri-n-octylphosphine oxide has CAS number 78-50-2 and molecular formula C24H51OP. Full identity and purity specifications are provided on the Certificate of Analysis with each lot.
What is the price of bulk TOPO and how is it supplied?
TOPO pricing is quote-based and depends on purity grade, volume, and packaging. It is supplied as a solid specialty additive. Submit a bulk quote request with your target volume and required purity for current pricing, CoA, and SDS.
What is the REACH and TSCA regulatory status of Tri-n-octylphosphine Oxide (TOPO)?
Tri-n-octylphosphine Oxide (TOPO) (CAS 78-50-2) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 201-121-3).