A simple method for the high-yield preparation of (NH4)(2)[Re2F8]center dot 2H(2)O has been developed that involves the reaction of (n-Bn4N)(2)[Re2Cl8] with molten ammonium bifluoride (NH4HF2). Using this method, the new salt [NH4](2)[Re2F8]center dot 2H(2)O was prepared in similar to 90% yield. The product was characterized in solution by ultraviolet-visible light (UV-vis) and F-19 nuclear magnetic resonance (F-19 NMR) spectroscopies and in the solid-state by elemental analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy. Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were performed to investigate the molecular and electronic structure, as well as the electronic absorption spectrum of the [Re2F8](2-) anion. The metal-metal bonding in the Re-2(6+) unit was quantified in terms of effective bond order (EBO) and compared to that of its [Re2Cl8](2-) and [Re2Br8](2-) analogues.