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- Name : Rhodium
- Symbol : Rh
- Atomic # : 45
- Atom weight: 102.906
- Melting P. : 1966
- Boiling P. : 3727
- Oxidation : +3
- Pronounced : RO-di-em
- From : Greek rhodon "rose"
- Identified : William Hyde Wollaston in 1803
- Appearance : Silvery white, hard metal
- Note : Often found in nature in the company of platinum
-
- [Properties]
-
- Rhodium and a few other metals always accompany lodes of platium. Wherever
- there is platinum in the earth, there is rhodium ad well. Most rhodium is
- extracted from a sludge that remains after platinum is removed from the ore.
- A high percentage of rhodium is also found in certain nickel deposits in
- Canada. The extraction processes are quite similar in principal.
- Rhodium is so hard and corrosion-resistant that it can be refined by
- simply dissolving away other metals and impurities. This is the same
- approach that William H. Wollaston used when he discovered the element
- nearly two centuries ago.
- Assuming the platinum has already been removed, any osmium and ruthenium
- can be removed by forming their volatile oxides. Iridium and palladium can
- be removed by adding ammonium and chlorine compounds. The rhodium compounds
- that remain can be reduced with titanium trichloride.
-