Tantalum is a chemical element with the symbol Ta and atomic number 73. Tantalum is very rare, very conductive to heat and electricity, hard, and has a blue-gray color. It is a transitive metal and has a very high corrosion resistance. It is a refractory metal that is rarely used in alloys but is used in laboratories as an excellent substitute for platinum. Tantalum has a melting point of 3017 ° C and a boiling point of 5458 ° C.