1860,1882

Caesium

• Robert Bunsen and Gustav Kirchhoff
• built a flame emission spectroscope in 1859
• and in 1860 discovered caesium,
• the first element discovered by spectroscope.
• The spectrographic analysis of mineral water
• presented two bright lines for caesium
• so they named it after the Latin word
• for the color of its lines, “deep blue.”
• After distilling forty tons of this water,
• they obtained seventeen grams of caesium oxide.
• In 1882, one of Bunsen’s students, Carl Setterberg,
• got pure caesium from electrolysis of caesium cyanide.

Atomic number 55

• Caesium formate for drilling fluids.
• Caesium atom transitions in atomic clocks.
• Caesium vapor to generate electricity from heat,
• to neutralize the space charge in vacuum tubes,
• and to emit light in magnetometers.
• Caesium in photoelectric cells.
• Caesium iodide and bromide in radiation detectors.
• Caesium nitrate in infrared flares.

Impermanence

• Radioactive caesium-137,
• seven-eighths gone in a lifetime,
• produced in nuclear power plants
• by decay of uranium to xenon to caesium,
• and we used to think
• we would live, it seemed, forever.