Organometallic rubidium and cesium compounds of the 5,6;11,12-di-o-phenylene-tetracene dianion.

See more Cesium products. Cesium (or Caesium) (atomic symbol: Ce, atomic number: 55) is a Block S, Group 1, Period 6 element with an atomic weight of 132.9054519. The number of electrons in each of Cesium's shells is 2, 8, 18, 18, 8, 1 and its electron configuration is [Xe]6s¹. The cesium atom has a radius of 265 pm and a Van der Waals radius of 343 pm. Cesium is a member of the alkali group of metals. It is one of three metals that occur as a liquid at room temperature, the others being mercury and gallium. Cesium's main commercial source is pollucite ore; however, it is also found in beryl, avogadrite, pezzottaite, and londonite. Cesium was discovered by Robert Bunsen and Gustav Kirchhoff in 1860 and first isolated by Carl Setterberg in 1882. In its elemental form, cesium has a silvery gold appearance. The word Cesium originates from the Latin word "caesius," meaning "sky blue," which refers to the vibrant blue lines in its spectrum.

See more Rubidium products. Rubidium (atomic symbol: Rb, atomic number: 37) is a Block S, Group 1, Period 5 element with an atomic weight of 5.4678. The number of electrons in each of Rubidium's shells is [2, 8, 18, 8, 1] and its electron configuration is [Kr] 5s¹. The rubidium atom has a radius of 248 pm and a Van der Waals radius of 303 pm. Rubidium is highly reactive, with properties similar to other Group 1 alkali metals, e.g., rapid oxidation in air. In its elemental form, rubidium has a gray white appearance. Rubidium is found in the minerals lepidolite, leucite, pollucite, carnallite, and zinnwaldite as well as some potassium minerals. Rubidium was discovered by Robert Bunsen and Gustav Kirchhoff in 1861 and was first isolated by George de Hevesy. The name Rubidium, originates from the Latin word rubidus, meaning "dark or deepest red."