astatine [At]

Introduction

From the Greek astatos meaning unstable. First produced in 1940 by DR Corson, KR MacKenzie & E Segre at the University of California, Berkeley by bombarding a bismuth isotope with alpha particles (helium nuclei).

Occurrence

• rarest of 92 naturally occurring elements
• < 30 g exists on earth at any one time
• occurs as a natural by-product of uranium & thorium decay

Characteristics

• radioactive halogen element
• solid non-metal of unknown color at room temperature
• very radioactive; decays quickly

Uses

none

More general terms

• halogen
• radioactive element

Additional terms

• periodic table