A sealed ampole containing cesium metal

Facts about Cesium:

  • Cesium: Soft, silvery-golden coloured metal
  • Fun fact about Cesium: Cesium has a melting temperature of 28.5 °C which means on a hot day it appears as a liquid.
  • Chemical symbol: Cs
  • Atomic number: 55

A crystal structure containing Cesium:

A sulfate bridged cesium crown ether.  Cesium atoms shown in purple.

Facts about this structure:

  • Formula: C24 H50 Cs2 O20 S2,4(H2 O)
  • Structure name: bis(μ2-Hydrogen sulfato-O,O')-bis(18-crown-6)-di-cesium tetrahydrate
  • Fun fact about the structure: The compound undergoes a change as it is heated, releasing the crown ether, which is reversed as it cools
  • CSD refcode: BOLLEU (What's this?)
  • Associated publication: D.Braga, E.Modena, M.Polito, K.Rubini, F.Grepioni, New Journal of Chemistry, 2008, 32, 1718, DOI: 10.1039/b805203d

More info:

Cesium (or Caesium with its official spelling) is highly reactive, exploding or bursting into flames with water and air respectively. Robert Bunsen (of Bunsen burner fame) and Gustav Kirchhoff discovered cesium in 1860. It has uses in drilling fluids and atomic clocks.

More info about the International Year of the Periodic Table (IYPT) in crystals project:

This project (#IYPTCrystals) is part of the International Year of the Periodic Table celebration (#IYPT2019), read more about the project here. You can follow us on social media using #IYPTCrystals and learn more about the wonders of crystals by following the CCDC on Twitter @ccdc_cambridge on Facebook ccdc.cambridge, on Instagram ccdc_cambridge or on YouTube CCDCCambridge.

If you want to find out more about some of the terms and concepts we have a Frequently Asked Questions Page.

A visualisation showing the structure containing Cesium alongside other structures published in the same scientific article: