All practice pages/Interatomic theory/Elements
Element 81, a post-transition metal
A soft metal named for a green spectral line, and a tasteless, odorless poison once called the poisoner's poison.
Period 6, group 13. The other post-transition metals are tinted, and every cell opens its own article.
A metal that gives up its valence electrons to form positive ions, though less readily than the metals to its left.
Rare, found in trace amounts in sulfide ores of zinc, lead and copper and recovered from the dust of smelting them.
William Crookes found it in 1861 as a bright green line in the spectrum of residue from a sulfuric acid plant, and Claude-Auguste Lamy isolated the metal in 1862. Crookes named it from the Greek thallos, green shoot.
Infrared detectors and optics, special low-melting glass, and electronics. Thallium-201 was long used in heart scans. Thallium sulfate was once a rat poison and insecticide, but it is now banned in many countries.
Extremely toxic, and it can be absorbed through the skin. Its salts have no taste or smell, which made them a favorite of poisoners. Prussian blue is the antidote.