The perrhenate anion is tetrahedral, being similar in size and shape to perchlorate and the valence isoelectronic permanganate.
The perrhenate anion is stable over a broad pH range and can be precipitated from solutions with the use of organic cations.
[6] Perrhenate may undergo condensation with formation of small rhenium polyoxometalate Re4O2−15 [7] where one central Re has octahedral oxygen coordination while 3 other are tetrahedral.
For this reason, perrhenate is sometimes used as a carrier for trace levels of pertechnetate, for instance in nuclear medicine scanning procedures.
Perrhenate is also used as a safer alternative to pertechnetate for nuclear waste vitrification studies, such as volatility[9] or encapsulation in solids.