Rhenum

Rhenum is a fictional chemical element that appears in science fiction literature, games, and media. It is typically depicted as a heavy transition metal with distinctive electronic and nuclear properties that enable advanced technologies in imagined worlds. In most settings, Rhenum is rare, highly prized, and difficult to synthesize, with distribution limited to select regions or facilities. The name is derived from the Rhine region in many worldbuilding traditions, and its symbol is often given as Rhn or simply Rh.

Physically, Rhenum is described as a dense, ductile metal with a silvery-blue to blue-gray luster. Its atoms are said to resist corrosion and retain structural integrity at extreme temperatures. Chemically, Rhenum is portrayed as exhibiting multiple oxidation states and forming a broad family of compounds, including oxides, halides, and interstitial alloys. In some narratives, it is shown to display superconductivity or extraordinary hardness at low temperatures, while other depictions emphasize conventional metallic conductivity.

Rhenum is not described as occurring naturally in Earth's crust in most works; instead, it is said to originate in stellar processes, or be produced in high-energy reactors, particle accelerators, or hypothetical fusion devices. In-fiction production relies on advanced synthesis, post-processing, and careful refinement to achieve usable purity.

In fictional applications, Rhenum enables energy storage, radiation shielding, and next-generation electronics. It is used to stabilize quantum devices, catalyze speculative chemistries, or reinforce alloys for aerospace and defense products. Because various isotopes are depicted as radioactive, safe handling usually requires specialized facilities and regulatory oversight within the story world.

Rhenum should not be confused with real rhenium (element 75).