Hexavalent hydrogen complex in hypothetical Y2CrH6

► A possible synthesis of Y2CrH6 was theoretically investigated. ► We found the thermodynamically stable structure with a hexavalent [CrH6]6−. ► The large charge state of [CrH6]6− brings diversity to the cation combinations. ► The large charge state would provide a chemical flexibility to the complex hydride.