2KReO4 + 16HI + 2KI → 2K2[ReI6] + 3I2 + 4H2O
Potassium perrhenate react with hydrogen iodide and potassium iodide to produce potassium hexaiodorhenate(IV), iodine and water. Hydrogen iodide - diluted solution. The reaction takes place in a boiling solution.