Tantalum is a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide.
Melting point: 3017 °C Boiling point: 5458 °C
A foil is a thin sheet of pure metal. Given its fragile nature, some foils have protective coatings.