Not to be confused with cerium. The Particular download cs4 chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy.
Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids, but it has a range of applications in the production of electricity, in electronics, and in chemistry. It is a very ductile, pale metal, which darkens in the presence of trace amounts of oxygen. The golden colour of caesium comes from the decreasing frequency of light required to excite electrons of the alkali metals as the group is descended. Addition of a small amount of caesium to cold water is explosive. Caesium metal is highly reactive and very pyrophoric. The chemistry of caesium is similar to that of other alkali metals, in particular rubidium, the element above caesium in the periodic table.
27 small grey spheres in 3 evenly spaced layers of nine. 8 spheres form a regular cube and 8 of those cubes form a larger cube. The grey spheres represent the caesium atoms. The center of each small cube is occupied by a small green sphere representing a chlorine atom. Many of the simple salts are hygroscopic, but less so than the corresponding salts of lighter alkali metals.
It rapidly etches the surface of semiconductors such as silicon. The auride anion here behaves as a pseudohalogen. 6, the number typical for the smaller alkali metal cations. The stick and ball diagram shows three regular octahedra, which are connected to the next one by one surface and the last one shares one surface with the first. All three have one edge in common.
All eleven vertices are purple spheres representing caesium, and at the center of each octahedron is a small red sphere representing oxygen. More so than the other alkali metals, caesium forms numerous binary compounds with oxygen. Binary compounds with sulfur, selenium, and tellurium also exist. 662 keV gamma emission with an 85. The radioactive 135Cs has a very long half-life of about 2. 3 million years, longest of all radioactive isotopes of caesium.