Name       : Thallium
Symbol     : Tl
Atomic #   : 81
Atom weight: 204.38
Melting P. : 303.5
Boiling P. : 1457
Oxidation  : +1, +3
Pronounced : THAL-i-em
From       : Greek thallos, "green twig"
Identified : Sir William Crookes in 1861
Appearance : Soft, gray metal
Note       : Very much like lead
             
[Properties]

  Although thallium can be found in ores such as crooksite, hutchinsonite,
and lorandite, these minerals are rather rare and sparsely distributed
around the world. Most thallium is recovered from the byproducts of lead
and zinc refining operations. It is also recovered from sulfuric acid
manufacturing processes that begin with certain pyrites.
  The exact refining procedure depends on the source of the metal. The
general idea, however, is to dissolve the mixture in hydrochloric acid to
produce a precipitate of thallious chloride, or thallium (I) chloride, TlCl.
This heavy compound is easily separated from the other substances by
filtering and drying it.
