Abstract: | Ethyltriphenylphosphonium perrhenate, (C20H20P)ReO4], and (iodomethyl)triphenylphosphonium perrhenate, (C19H17IP)ReO4], have been crystallized from 2‐propanol. Both crystal structures consist of phosphonium cations and perrhenate anions. The cations show the typical propeller‐like geometry. In both crystals, the positions of the nearly tetrahedral anions are stabilized by weak C—H?O hydrogen bonds, and for the latter compound, I?π interactions also occur. |