The symbol for the element Rhenium is RE, which is two letters. Rhenium is a chemical element with the atomic number of 75 and is a silvery-white, heavy, third-row transition metal in the periodic table. It is one of the rarest elements in the Earth's crust and is found in trace amounts in platinum ores. Rhenium has the highest melting point of any element and is used in alloys, catalysts, and electronics.