Naturally occurring tantalum consists of its one stable isotope, 181Ta.

Tantalum is a rare, shiny, gray, dense metal. It is highly ductile and can be drawn into a thin wire. Tantalum is highly corrosion resistant due to the formation of an oxide film. It is an excellent conductor of heat and electricity.

The metal has a melting point exceeded only by tungsten and rhenium. Tantalum is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refractory metals are tungsten, molybdenum, rhenium and niobium.