Perrhenate

The perrhenate ion is the anion with the formula ReO−
4, or a compound containing this ion. 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. At normal pH, perrhenate exists as metaperrhenate (ReO−
4), but at high pH mesoperrhenate (ReO3−
5) forms. Perrhenate, like its conjugate acid perrhenic acid, features rhenium in the oxidation state of +7 with a d configuration. Solid perrhenate salts takes on the color of the cation.