[2] It can be created by slowly exposing elemental rubidium to oxygen gas:[3] Like other alkali metal hyperoxides, crystals can also be grown in liquid ammonia.

[3] An even more oxygen rich compound, that of rubidium ozonide (RbO3) can be created using RbO2.

[5] Roughly speaking, RbO2 has a crystal structure similar to tetragonal calcium carbide, but is rather distorted due to the Jahn–Teller effect, which makes the crystal structure less symmetrical.

[2] RbO2 is stable in dry air, but is extremely hygroscopic.

[3] The compound has been studied as an example of magnetism arising intrinsically from the p-shell.