Orbital molecules in electronic materials

Orbital molecules are made up of coupled orbital states on several metal ions within an orbitally ordered (and sometimes also charge-ordered) solid such as a transition metal oxide. Spin-singlet dimers are known in many materials, but recent discoveries of more exotic species such as 18-electron heptamers in AlV2O4 and magnetic 3-atom trimerons in magnetite (Fe3O4) have shown that orbital molecules constitute a general new class of quantum electronic states in solids.