Caesium (Cs)
Element number 55, from the alkali metals family.
Caesium facts
- Symbol
- Cs
- Atomic number
- 55
- Atomic mass
- 132.91
- Family
- Alkali metals
- Period
- 6
- Group
- 1
Famous reactions with caesium
- KABOOM! Caesium meets WaterCaesium hydroxide + hydrogen gas 2Cs + 2H₂O → 2CsOH + H₂ · At room temperature · Try it
What does caesium react with?
Caesium makes a new substance with 10 other elements and chemicals in our lab:
- Caesium + HydrogenCaesium hydride 2Cs + H₂ → 2CsH · When heated · Try it
- Caesium + OxygenCaesium superoxide Cs + O₂ → CsO₂ · When heated · Try it
- Caesium + FluorineCaesium fluoride 2Cs + F₂ → 2CsF · At room temperature · Try it
- Caesium + SulfurCaesium sulfide 2Cs + S → Cs₂S · When heated · Try it
- Caesium + ChlorineCaesium chloride 2Cs + Cl₂ → 2CsCl · At room temperature · Try it
- Caesium + SeleniumCaesium selenide 2Cs + Se → Cs₂Se · When heated · Try it
- Caesium + BromineCaesium bromide 2Cs + Br₂ → 2CsBr · At room temperature · Try it
- Caesium + TelluriumCaesium telluride 2Cs + Te → Cs₂Te · When heated · Try it
- Caesium + IodineCaesium iodide 2Cs + I₂ → 2CsI · At room temperature · Try it
- Caesium + Hydrochloric AcidCaesium chloride + hydrogen gas 2Cs + 2HCl → 2CsCl + H₂ · At room temperature · Try it
It also blends into a mixture, like an alloy, with 74 other metals when melted together.
Nothing happens when it's simply mixed with 13 of the others. 21 pairings have never been tried, because not enough atoms have ever existed.