Potassium perrhenate
Potassium perrhenate is an inorganic compound with the chemical formula KReO4. Preparation 
Potassium perrhenate can be produced by the neutralization of potassium hydroxide and perrhenic acid. Properties
Potassium perrhenate is a white solid that is sparingly soluble in water and ethanol. It have a tetragonal crystal system with the space group I41/a (No. 88), and lattice constants a = 567.4 pm and c = 1266.8 pm. It is a strong oxidizer. References

Potassium compounds
Perrhenates