We demonstrate, by means of fully unconstrained density functional theory calculations, that cluster Zn17 endohedrally doped with a Cr impurity can be qualified as a magnetic superalkali cluster. We explain the origin of its high stability, its low vertical ionization potential and its high total spin magnetic moment which amounts to 6 μB, exactly the same value as that of the isolated Cr atom. With the aim of exploring the possibility of designing a bistable magnetic nanoparticle, with a corresponding inter-unit exchange coupling, we also consider the assembling of two such units through different contact regions and in different magnetic configurations. Furthermore, we analyze up to which extent is the Zn shell able to preserve the electronic properties of the embedded Cr atom, both against coalescence of the two superatoms forming the magnetically bistable nanoparticle, and upon the adsorption of an O2 molecule or even under an oversaturated O2 atmosphere. Our results are discussed not only emphasizing the fundamental physical and chemical aspects, but also with an eye on the new prospects that those Cr@Zn17 magnetic superalkali clusters (and others of similar kind) may open in spintronics-, molecular electronics- or biomedical-applications. © 2015 Owner Societies.