Classification of Thallium
Elemental Category
Thallium is categorized as a post-transition metal. It occupies Group 13 of the periodic table, positioned beneath indium.
Macroscopic Physical Characteristics
Appearance and Feel
When freshly cut or polished, thallium displays a distinct bluish-white metallic luster, similar to that of lead or tin. However, its surface rapidly tarnishes to a grayish hue upon exposure to the air due to oxidation. The metal is notably soft, allowing it to be easily cut with a knife. It is also highly malleable and ductile, meaning it can be readily shaped and drawn into thin wires.
State at Room Temperature
At typical room temperatures (approximately 20-25 °C), thallium exists in a solid state.
Thermal Properties
Phase Transition Temperatures
Thallium has a relatively low melting point for a metal, recorded at approximately 304 °C. Its boiling point is considerably higher, estimated to be around 1473 °C.