Atomic number: 98

Symbol: Cf

Category: actinide 

Density at 25°C: solid: density: 15.1 g·cm−3

This radioactive element was first created at the University of California, Berkeley, hence it's name in this case. It is mainly used as a powerful neutron emitter. It is also the heaviest element that occasional occurs in tiny amounts naturally in very concentrated uranium ores.

A very small magnified disc of californium about 1mm across. image: adapted from wikipedia

Use, natural applications or common combinations: 

  • neutron emitter for neutron spectroscopy and other measuring techniques.
  • for formation of heavier elements.

Basic characteristics:

  • Standard atomic weight: (251)
  • Melting point:  900 °C [±30°C depends on form]
  • Boiling point:  1470 °C
  • Radioactivity: all radioactive
    • 251Cf with half life of 898 years via alpha only decay
    • 249Cf half life of 351 years used for making heavier elements.