Caesium sesquioxide is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

or . In terms of

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

s, Caesium in this compound has a nominal charge of +1, and the oxygen is a mixed

peroxide In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen p ...

() and

superoxide In chemistry, a superoxide is a compound that contains the superoxide ion, which has the chemical formula . The systematic name of the anion is dioxide(1−). The reactive oxygen ion superoxide is particularly important as the product of t ...

() for a structural formula of . Compared to the other caesium oxides, this phase is less well studied, but has been long present in the literature. It can be created by thermal decomposition of

caesium superoxide Caesium superoxide is the superoxide of caesium. It is an orange solid. Preparation Burning caesium in excess oxygen will produce caesium superoxide. : Properties Caesium superoxide's crystal structure is same as calcium carbide. It contains ...

at 290 °C. : The compound is often studied as an example of a Verwey type

charge ordering Charge ordering (CO) is a (first- or second-order) phase transition occurring mostly in strongly correlated materials such as transition metal oxides or organic conductors. Due to the strong interaction between electrons, charges are localized on ...

transition at low temperatures. There were some theoretical suggestions that would be a ferromagnetic half metal, but along with the closely related

rubidium sesquioxide Rubidium sesquioxide is a chemical compound with the formula or . In terms of oxidation states, Rubidium in this compound has a nominal charge of +1, and the oxygen is a mixed peroxide () and superoxide () for a structural formula of . It has bee ...

, experimental results found a magnetically frustrated system. Below about 200 K, the structure changes to tegragonal symmetry.

Electron paramagnetic resonance Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spin ...

and

nuclear magnetic resonance Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

measurements show a complicated low temperature magnetic behavior that depends on the orientation of the oxygen dimers and superexchange through the caesium atoms.

References

Caesium compounds Sesquioxides {{inorganic-compound-stub