Caesium peroxide

Caesium peroxide
Names
	IUPAC name Caesium peroxide
Identifiers
CAS Number	12053-70-2;
3D model (JSmol)	Interactive image;
ChemSpider	10737153;
	InChI InChI=1S/2Cs.O2/c;;1-2/q2*+1;-2 Key: HNZHVTZRIBKSIO-UHFFFAOYSA-N;
	SMILES [Cs+].[Cs+].[O-][O-];
Properties
Chemical formula	Cs2O2
Molar mass	297.809 g·mol−1
Appearance	Yellowish
Structure
Crystal structure	Orthorhombic
Related compounds
Other cations	Lithium peroxide; Sodium peroxide; Potassium peroxide; Rubidium peroxide;
Related caesium oxides	Caesium suboxide; Caesium monoxide; Caesium sesquioxide; Caesium superoxide; Caesium ozonide;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Caesium peroxide or cesium peroxide is an inorganic compound of caesium and oxygen with the chemical formula Cs₂O₂. It can be formed from caesium metal by adding a stoichiometric amount in ammonia solution, or oxidizing the solid metal directly.

2 Cs + O₂ → Cs₂O₂

It can also be formed by the thermal decomposition of caesium superoxide:

2 CsO₂ → Cs₂O₂ + O₂

Upon heating until 650 °C, the compound will decompose to caesium monoxide and atomic oxygen:

Cs₂O₂ → Cs₂O + [O]

Caesium peroxide shows a Raman vibration at 743 cm⁻¹, due to the presence of the peroxide ions. The compound is often used as a coating for photocathodes, due to its low work function.