Rubidium superoxide or Rubidium hyperoxide is a compound with the formula . 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, the negatively charged

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 ...

and positively charged rubidium give it a structural formula of (Rb⁺)(O₂⁻).

Chemistry

It can be created by slowly exposing elemental rubidium to

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

gas: :Rb(s) + O₂(g) → RbO₂(s) Like other alkali metal hyperoxides, crystals can also be grown in liquid

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

. Between 280 and 360 °C, Rubidium superoxide will

decompose Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ...

, leaving not

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

(Rb₂O₃), but rather rubidium peroxide (Rb₂O₂). :RbO₂ (s) → 1/2 R₂O₂(s) + 1/2 O₂(g) An even more oxygen rich compound, that of

rubidium ozonide Rubidium ozonide is an oxygen rich compound of rubidium. It is an ozonide, meaning it contains the ozonide anion (O3−). It can be created by reacting rubidium superoxide (RbO2) with ozone (O3) in a liquid ammonia Ammonia is an inorganic ...

(RbO₃) can be created using RbO₂.

Properties

Roughly speaking, RbO₂ has a crystal structure similar to tetragonal

calcium carbide Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of Ca C2. Its main use industrially is in the production of acetylene and calcium cyanamide. The pure material is colorless, while pieces of te ...

, but is rather distorted due to the

Jahn–Teller effect The Jahn–Teller effect (JT effect or JTE) is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in sp ...

, which makes the crystal structure less symmetrical. RbO₂ is stable in dry air, but is extremely

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substan ...

. The compound has been studied as an example of magnetism arising intrinsically from the p-shell. RbO₂ has been predicted to be a

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...

Mott insulator Mott insulators are a class of materials that are expected to conduct electricity according to conventional band theories, but turn out to be insulators (particularly at low temperatures). These insulators fail to be correctly described by band ...

. At low temperatures, it transitions to

antiferromagnetic In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions. ...

order, with a

Neel temperature In physics and materials science, the Curie temperature (''T''C), or Curie point, is the temperature above which certain materials lose their permanent magnetic properties, which can (in most cases) be replaced by induced magnetism. The Cur ...

of 15 K.

References

Rubidium compounds Superoxides {{inorganic-compound-stub

Chemistry

Properties

See also

References