 The most common oxide is the volatile colourless Re2O7 . Rhenium trioxide <unk> adopts a perovskite @-@ like structure . Other oxides include <unk> , <unk> , and <unk> . The sulfides are <unk> and <unk> . <unk> salts can be converted to <unk> by the action of ammonium hydrosulfide . 
