Bunsen, Robert Wilhelm cesium discovered

Bunsen, Robert Wilhelm. (1811-1899). Bom in Germany, Bunsen is remembered chiefly for his invention of the laboratory burner named after him. He engaged in a wide range of industrial and chemical research, including blast-furnace firing, electrolytic cells, separation of metals by electric current, spectroscopic techniques (with Kirchhoff), and production of light metals by electrical decomposition of their molten chlorides. He also discovered two elements, rubidium and cesium. 

In the 1859 the chemist Robert Wilhelm Bunsen and his younger colleague, the physicist Gustav Kirchhoff, discovered a surprising phenomenon of spectroscopy. The emission and absorption spectra of an element are identical. They thus put into place an ideal tool for the discovery and identification of elements. Indeed, they themselves discovered cesium (1860) and rubidium (1861). In total, at least 20 elements were found by using spectroscopic technigues (including X-ray spectroscopy). 

The name comes from the Latin caesius, meaning sky blue. Cesium was discovered by Robert Wilhelm Bunsen (1811-1899) and Gustav Robert Kirchhoff (1824-1887) in 1860. They used a spectroscope on a drop of mineral water and saw previously unnoted blue lines in the spectra. Cesium is rare, but it is used in photoelectric cells and as a hydrogenation catalyst. It is also used in some atomic clocks. 

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