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.