Elemental Cesium in a Glass Ampoule Under Argon

- Image ID: A5AXKW
Elemental Cesium in a Glass Ampoule Under Argon
Phil Degginger / Alamy Stock Photo
Image ID: A5AXKW
Caesium or cesium (pronounced /ˈsiːziəm/) is the chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (83 °F), which makes it one of only five metals that are liquid at or near room temperature. Caesium is most notably used in atomic clocks.