Rubidium sesquioxide

Rubidium sesquioxide is a chemical compound with the formula Rb₂O₃ or more accurately Rb₄O₆. In terms of oxidation states, Rubidium in this compound has a nominal charge of +1, and the oxygen is a mixed peroxide (O2−2) and superoxide (O−2) for a structural formula of (Rb⁺)₄(O−2)₂(O2−2).^[4] It has been studied theoretically as an example of a strongly correlated material.^[5]

Rubidium sesquioxide

Identifiers
3D model (JSmol)	Interactive image
PubChem CID	160136017
InChI InChI=1S/3O2.4Rb/c3*1-2;;;;/q-2;2*-1;4*+1 Key: QZSXBJDVQYXYOD-UHFFFAOYSA-N
SMILES [Rb+].[Rb+].[Rb+].[Rb+].[O-][O-].O=[O-].O=[O-]
Properties
Chemical formula	Rb4O6
Molar mass	437.865 g·mol−1
Appearance	Black crystals[1]
Melting point	461 °C (862 °F; 734 K)[2]
Structure[3]
Crystal structure	Pu2C3 structure type (body-centered cubic)
Space group	I43d (No. 220)
Lattice constant	a = 932 pm
Formula units (Z)	4
Related compounds
Other cations	Caesium sesquioxide
Related rubidium oxides	Rubidium suboxide Rubidium oxide Rubidium peroxide Rubidium superoxide Rubidium ozonide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The compound was predicted to be a rare example of a ferromagnetic compound that is magnetic due to a p-block element,^[6] and a half-metal that was conducting in the minority spin band.^[7] However, while the material does have exotic magnetic behavior, experimental results instead showed an electrically insulating magnetically frustrated system.^[1][5] Rb₄O₆ also displays a Verwey transition where charge ordering appears at 290 K.^[8]

Rubidium sesquioxide can be prepared by reacting the peroxide Rb₂O₂ and the superoxide RbO₂:^[2]

Rb₂O₂ + 2 RbO₂ → 2 Rb₂O₃

It is initially discovered in 1907,^[9][3] and more thoroughly characterized in 1939.^[10] The compound crystallizes in a body-centered cubic form with the same crystal structure as Pu₂C₃ and Cs₄O₆.^[10][3]

See also

• Rubidium oxide