atomic number 81

Từ điển WordNet v3.1 - WordNet Dictionary

noun

a soft grey malleable metallic element that resembles tin but discolors on exposure to air;
it is highly toxic and is used in rodent and insect poisons;
occurs in zinc blende and some iron ores
• Syn:
thallium, Tl
• Hypernyms:
metallic element, metal
• Substance Holonyms:
zinc blende, blende, sphalerite