Chemical Properties/Reaction Tendencies of Thallium
The coating on Thallium is not protective as it is for other metals such as
copper or aluminum. Since Thallium does not have a protective coating on it,
the black oxide and hydroxide will eventually fall off, which allows the fresh
metal to be exposed, but the fresh metal will soon corrode away. This such
process continues until all of the metal has completely been destroyed. When Thallium is exposed to air, it builds up a heavy oxide, and when
it is exposed to air, it will form a hydride. Thallium is the heaviest of the
Group IIIA elements. Thallium forms twenty-five
isotopic forms. A mixture of two different isotopes forms natural Thallium.