Caesium superoxide

Caesium superoxide is a chemical compound with the chemical formula CsO₂. It consists of caesium cations Cs⁺ and superoxide anions O−2. It is an orange solid.

Caesium superoxide

Caesium cations, Cs+   Superoxide anions, O−2
Identifiers
CAS Number	12018-61-0 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/Cs.HO2/c;1-2/h;1H/q+1;/p-1 Key: DZWLBLJPRRQKGB-UHFFFAOYSA-M
SMILES [Cs+].[O-] [O]
Properties
Chemical formula	CsO2
Molar mass	164.903 g·mol−1
Appearance	Yellow to orange solid [1]
Density	3.77 g/cm3[1]
Melting point	600 °C[2]
Solubility in water	reacts
Related compounds
Other anions	Caesium oxide Caesium peroxide
Other cations	Lithium superoxide Sodium superoxide Potassium superoxide Rubidium superoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Burning caesium in excess oxygen will produce caesium superoxide.^[2]

Cs + O₂ → CsO₂

Properties

Caesium superoxide's crystal structure is same as calcium carbide. It contains direct oxygen-oxygen bonding.^[2]

It reacts with water to form hydrogen peroxide and caesium hydroxide.^[2]

2 CsO₂ + 2 H₂O → O₂↑ + H₂O₂ + 2 CsOH

Heating to approximately 400 °C induces thermal decomposition to caesium peroxide.^[3]

The standard enthalpy of formation ΔH_f⁰ of caesium superoxide is −295 kJ/mol.^[4]

Caesium superoxide reacts with ozone to form caesium ozonide.^[2]

CsO₂ + O₃ → CsO₃ + O₂