Answer:
Drilling fluids based on caesium formate are widely used in the extractive oil industry. It’s used in thermionic generators, which transform heat into electricity. Caesium chloride and caesium sulphate are commonly used in molecular biology due to the high density of caesium.
Reaction of caesium(Cs) with halogen
Alkali metals readily react with halogens to form ionic halides. Caesium metal forms caesium halides as it reacts strongly with all halogens. As a result, it reacts with chlorine (Cl2) to produce caesium(I) chloride (CsCl).
2Cs + Cl2 → 2CsCl