Americium

Atomic number: 95

Symbol: Am

Category: actinide 

Density at 25°C: solid: density: 12 g·cm−3

This element radioactive element is most widely  found  in smoke detectors, as part of section called a an ionization chamber. It has been proposed as a fuel for nuclear powered spacecraft.  It was named Americium as it sits just below Europium on the periodic table


A very small button of americium viewed under a microscope. image: adapted from wikipedia

Americium was first produced in 1944 by the group of Glenn T. Seaborg at the University of California, Berkeley.


Use, natural applications or common combinations: 

  • Smoke detectors - for producing alpha particles
  • Existing americium is found in the areas used for nuclear weapons tests in the atmosphere  between 1945 and 1980
  • Neutron source when pressed with beryllium
  • portable spectrometers alpha and gamma emitter. 


Basic characteristics:

  • Standard atomic weight: (243)
  • Melting point: 1176 °C
  • Boiling point:  2607 °C
  • Radioactivity: all radioactive
    • 241Am as americium oxide in smoke detectors has half-life of  432.2 years changing to neptunium via alpha decay.
    • 243Am half-life of 7370 years
    • 241Am half-life of 432.2 years