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.
