Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal.It is a noble metal and a member of the platinum group.It has only one naturally occurring isotope, 103 Rh. Naturally occurring rhodium is usually found as free metal, as an alloy with similar metals, and rarely as a chemical ...