Rhodium(III) chloride hydrate
CAS 20765-98-4
Rhodium(III) chloride hydrate is the principal soluble rhodium source — the precursor to hydroformylation and hydrogenation catalysts, rhodium plating baths, and the Rh/C and Rh/Al₂O₃ catalysts used in specialty hydrogenations.
Typical specification
| Molecular formula | RhCl₃ · xH₂O |
|---|---|
| Molecular weight | 209.26 (anhydrous basis) |
| Purity (metals basis) | ≥ 99.9% |
| Rhodium content | 38 – 40% (certified per lot) |
| Appearance | Dark red to red-brown crystals |
| Water solubility | Freely soluble (soluble hydrate form) |
| Base metals (Fe, Cu, Ni) | ≤ 100 ppm total, ICP per lot |
| Available forms | Crystals or solution at specified Rh g/L |
| HS code (export) | 2843900099 |
Lot-specific COA issued with every shipment. SDS and ICP elemental impurity data available on request.
Where RhCl₃·xH₂O is used
Hydroformylation catalyst precursor
The industrial entry point to Rh–phosphine oxo catalysts that convert olefins to aldehydes — the largest single application of rhodium in homogeneous catalysis, run at ppm-level Rh with rigorous metal accounting.
Catalyst and complex synthesis
Starting material for Wilkinson's catalyst RhCl(PPh₃)₃, [Rh(cod)Cl]₂, rhodium carboxylates for carbene chemistry, and supported Rh catalysts for arene ring hydrogenation under mild conditions.
Rhodium electroplating
Feeds the sulfate and phosphate plating baths that deposit bright, tarnish-proof rhodium finishes on jewelry, reflectors and electrical contacts.
Storage and shipping
Storage. Store tightly sealed and dry; hygroscopic. The soluble hydrate form should be kept from prolonged heating, which converts it toward insoluble anhydrous RhCl₃.
Shipping. Shipped in sealed fluorinated bottles with SDS. Given rhodium's price level, kilogram-value shipments move via insured valuables logistics.
Packaging. 1 g · 5 g · 25 g · 100 g · Solution grades by contained Rh weight
Synonyms
- Rhodium trichloride hydrate
- RhCl3 hydrate
- Rhodium chloride (soluble form)
- Rhodium(III) chloride trihydrate (commercial hydrate)
Frequently asked questions
Why does rhodium pricing need special care?
Rhodium is the most volatile-priced PGM, historically moving several percent in a day. Every quote states its fixing reference and validity window, and we recommend locking the metal leg the day you confirm — not the day you pay.
How is contained rhodium settled?
Each lot's Rh content (38–40%) is assayed and certified on the COA, and the invoice settles on assayed metal at the agreed fixing plus conversion — the standard practice for high-value PGM salts.
Do you supply plating-bath concentrates?
Yes — rhodium sulfate and phosphate solutions at customer-specified Rh g/L for decorative and technical plating, with lot assay certificates.
Is recovery worthwhile for rhodium residues?
Almost always — at rhodium's price level even dilute residues carry significant value. Spent baths, catalyst residues and filter cakes are assayed on receipt and credited at the agreed fixing.