Rhenium (Re)

Retaining its crystalline structure at temperatures up to its melting point, rhenium ([Xe]4f¹⁴5d⁵6s²) (CAS 7440-15-5) is gray to black in powder form, silvery-white, and lustrous as a solid. It does not occur naturally. Rhenium has one of the highest densities, exceeded only by platinum, iridium, and osmium. Only tungsten has higher melting points. Rhenium has good wear resistance and can withstand arc corrosion. Rhenium's range of valences exceeds that of all other elements.