Low-Temperature Anharmonicity in Cesium Chloride (CsCl).

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.

Chlorine is a Block P, Group 17, Period 3 element. Its electron configuration is [Ne]3s²3p⁵. The chlorine atom has a covalent radius of 102±4 pm and its Van der Waals radius is 175 pm. In its elemental form, chlorine is a yellow-green gas. Chlorine is the second lightest halogen after fluorine. It has the third highest electronegativity and the highest electron affinity of all elements, making it a strong oxidizing agent. It is rarely found by itself in nature. Chlorine was discovered and first isolated by Carl Wilhelm Scheele in 1774. It was first recognized as an element by Humphry Davy in 1808.