Periodic Table · element

Actinium

Ac · Z 89

atomic number

89

atomic mass

227

notation

Ac

group

f-block: Actinide

period

7

state0c

Solid

state20c

Solid

occurrence

From Decay

density

10

melting pt

1050

boiling pt

3198

discovered

1902

abundance

5.5e-10

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From the All Periodical Elements database in Notion, last edited 2026-08-15. This page is the row, rendered by the build; nothing on it is written by hand.