German chemist · 1811–1899
Robert Bunsen
Robert Bunsen helped invent spectroscopy, the technique that reads an element’s identity from the colours of light it gives off. With Gustav Kirchhoff he used it to discover caesium in 1860 and rubidium in 1861.
- Elements credited
- 2
- Discoveries
- 1860–1861
- Co-discoverers
- 1
- Where
- Germany
The work
Flame tests had long been used to recognise elements by colour, but mixtures confused the eye. In 1859 Bunsen and Kirchhoff passed the light through a prism and saw that each element produces its own pattern of sharp bright lines.
Bunsen evaporated 40 tonnes of mineral water from Dürkheim and found two blue lines belonging to no known element. He named the new metal caesium, from the Latin for sky blue. A year later two deep red lines in the mineral lepidolite revealed rubidium, from the Latin for deep red.
Caesium and Rubidium side by side
Life and career
Bunsen was born in Göttingen, the son of a professor, and taught in Kassel, Marburg and Breslau before settling in Heidelberg in 1852, where he remained until he retired.
Early in his career he lost the sight of one eye in an explosion while studying arsenic compounds and nearly died of arsenic poisoning. He was a famous teacher whose students and visitors included Auer von Welsbach and, briefly, Mendeleev. He never married.
Also known for
- The Bunsen burner, developed with his technician Peter Desaga
- The Bunsen cell, a cheap carbon–zinc battery
- Iron oxide hydrate as an antidote to arsenic poisoning