Spinels are oxides with chemical formulas of the type
AB2O4, where A is a divalent metal cation (positive ion), B is a
trivalent metal cation, and O is oxygen. Spinels are valued for
their beauty, which derives from the molecules’ spatial
configurations, but spinels in which the trivalent cation B
consists of the element chrome (Cr) are interesting for a reason
that has nothing to do with aesthetics: They have magnetic
properties with an abundance of potential technological
applications, including gas sensors, drug carriers, data storage
media, and components of telecommunications systems.