Periodic Table · element

Thallium

Tl · Z 81

atomic number

81

atomic mass

204.38

notation

Tl

group

13: Boron

period

6

state0c

Solid

state20c

Solid

occurrence

Primordial

density

11.85

melting pt

304

boiling pt

1473

discovered

1861

abundance

0.85

ore minerals

in zinc and lead sulfides

mined as

By-product

extraction

A trace in zinc- and lead-smelter flue dust; production is tiny and mostly a matter of keeping it out of the environment.

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From the All Periodical Elements database in Notion, last edited 2026-08-16. This page is the row, rendered by the build; nothing on it is written by hand.