Rhenium(VII) oxide is the inorganic compound with the formula Re2O7.

Re2O7 is the raw material for all rhenium compounds, being the volatile fraction obtained upon roasting the host ore.[2] Solid Re2O7 consists of alternating octahedral and tetrahedral Re centres.

Upon heating, the polymer cracks to give molecular (nonpolymeric) Re2O7.

This molecular species closely resembles manganese heptoxide, consisting of a pair of ReO4 tetrahedra that share a vertex, i.e., O3Re–O–ReO3.

Heating Re2O7 gives rhenium dioxide, a reaction signalled by the appearance of the dark blue coloration:[5] Using tetramethyltin, it converts to methylrhenium trioxide ("MTO"), a catalyst for oxidations:[6] In a related reaction, it reacts with hexamethyldisiloxane to give the siloxide:[4] Rhenium(VII) oxide finds some use in organic synthesis as a catalyst for ethenolysis,[7] carbonyl reduction and amide reduction.