This chapter contains sections titled: Foreword The Basics of Zirconium Cluster Chemistry Motivation Mixed Chloride–Iodide Zirconium Cluster Phases with a 6:12 Metal:Halide Ratio Mixed Chloride–Iodide Zirconium Cluster Phases with a 6:13 Metal:Halide Ratio Mixed Chloride–Iodide Zirconium Cluster Phases with a 6:14 Metal:Halide Ratio Mixed Chloride–Iodide Zirconium Cluster Phases with a 6:15 Metal:Halide Ratio Mixed Chloride–Iodide Zirconium Cluster Phases with a 6:18 Metal:Halide Ratio – Products from Solid-state Reactions Outlook Acknowledgments References