In this chapter, alternative views based on the structure have been presented in the spinel superconducting compounds, including the only oxide spinel superconductor, LiTi2O4, and non-oxide superconductors, CuIr2S4 and CuV2S4. Inspection of the atomic arrangements, electronic structures and bonding interactions of spinel superconductor, LiTi2O4 shows that LiTi2O4 can be interpreted as Li-doped TiO2, which is similar with doping Cu into TiSe2 to induce superconductivity. Different from LiTi2O4, the electronic structures of CuIr2S4 and CuV2S4 indicate a distinctive way to understand them in the structural viewpoint. The d6 electron configuration and the octahedral coordination of Ir in CuIr2S4 can be analogous to the d6 in perovskites, which sometimes host a metal-insulator transition. However, the superconductivity in CuV2S4 may be induced from the suppression of charge density waves. This kind of structural views will help chemists understand physical phenomena obviously more straightforward, though not sufficient, as clearly shown by the competition between each other, such as superconductivity and other structural phase transition (CDWs), oxidation fluctuation or magnsetism.
Part of the book: Magnetic Spinels