Ammonium pentachlororhodate(III) hydrate
CAS 63771-33-5
Ammonium pentachlororhodate is the classical refining and precipitation salt of rhodium chemistry — the crystalline intermediate through which rhodium is purified from PGM concentrates, and a convenient high-assay precursor to rhodium sponge, powder and plating chemistry.
Typical specification
| Molecular formula | (NH₄)₂[RhCl₅(H₂O)] |
|---|---|
| Molecular weight | 334.26 |
| Purity (metals basis) | ≥ 99.9% |
| Rhodium content | ≥ 30.0% (certified per lot) |
| Appearance | Red to red-brown crystalline powder |
| Solubility | Soluble in dilute HCl and hot water |
| Base metals (Fe, Cu, Ni, Pb) | ICP report per lot |
| Origin of metal | Primary and certified recycled feed, full assay traceability |
| HS code (export) | 2843900099 |
Lot-specific COA issued with every shipment. SDS and ICP elemental impurity data available on request.
Where (NH₄)₂RhCl₅·xH₂O is used
Rhodium refining and purification
The ammonium chlororhodate precipitation step is a standard operation in separating rhodium from other platinum-group metals and base metals; the crystalline salt is filtered, washed and calcined to give high-purity rhodium sponge or powder.
Precursor to rhodium metal and catalysts
Thermal decomposition under hydrogen yields rhodium metal directly, making the salt a convenient route to Rh powder, supported Rh catalysts and rhodium coatings without an intermediate dissolution step.
Plating and solution chemistry
Dissolved in acid it feeds rhodium plating bath make-up and replenishment, and serves as a defined chlororhodate source in coordination chemistry where a stable, weighable solid is preferred over deliquescent RhCl₃ hydrate.
Storage and shipping
Storage. Store sealed and dry, protected from light. Stable in air; avoid prolonged humidity.
Shipping. Ships in sealed fluorinated bottles with SDS. Given rhodium's value, higher-value lots move via insured valuables logistics.
Packaging. 1 g · 5 g · 25 g · 100 g · Custom lots by contained-metal weight
Synonyms
- Ammonium pentachlororhodate
- (NH4)2RhCl5
- Ammonium aquopentachlororhodate
- Diammonium pentachloroaquorhodate(III)
- Rhodium ammonium chloride salt
Frequently asked questions
How does this compare with rhodium trichloride hydrate?
The ammonium salt is a stable, free-flowing crystalline solid that weighs accurately and stores well, where RhCl₃ hydrate is hygroscopic with variable water content. Choose the ammonium salt for refining, calcination routes and precise weighing; choose the trichloride hydrate (CAS 20765-98-4) for direct aqueous complex synthesis.
How is rhodium priced and how do you handle its volatility?
Rhodium is the most volatile-priced PGM, historically moving several percent in a day. Every quote states its fixing reference and validity window; we recommend locking the metal leg the day you confirm the order rather than the day you pay.
What documentation is included?
A lot-specific certificate of analysis with assayed rhodium content and appearance, plus an English SDS. ICP trace-metal panels are available on request.
Do you take back rhodium residues?
Yes — at rhodium's price level recovery pays even on dilute streams. Spent baths, filter cakes and process residues are assayed on receipt and credited at the agreed fixing against future supply.