This paper describes an upper-division undergraduate exercise involving the synthesis and iodometric and infrared spectroscopic analysis of the peroxide double salt [Zn(NH[subscript 3])[subscript 4]][Mo(O[subscript 2])[subscript 4]]. Here, iodometric methods are employed to determine the peroxide content of the compound, a procedure widely used for the industrial analysis of peroxides. The exercise increases student proficiency in synthesis, the handling of reactive chemicals, and titrimetry, while introducing aspects of metal peroxide chemistry and key chemical concepts related to high-coordination number complexes, kinetic versus thermodynamic stability, and group theoretical treatments of vibration spectroscopy.