In the thallous series many analogies with lead compounds are observed; in the thallic some resemblance to aluminium and gold.
Thallous hydroxide, T10H, is most conveniently prepared by decomposing the solution of the sulphate with baryta water.
Thallous chloride, T1C1, is readily obtained from the solution of any thallous salt, by the addition of hydrochloric acid, as a white precipitate similar in appearance to silver chloride, like which it turns violet in the light and fuses below redness into a (yellow) liquid which freezes into a horn-like flexible mass.
Thallous iodide, T11, is obtained as a yellow precipitate, which requires 16,000 parts of cold water for its solution, by the addition of potassium iodide to a solution of a thallous salt, or by the direct union of its components.
Thallous bromide, TIBr, is a light yellow crystalline powder; it is formed analogously to the chloride.