Name: tantalum
Symbol: Ta
Atomic number: 73
Atomic weight: 180.9479 (1)
Group in periodic table: 5
Group name:
Period in periodic table: 6
Block in periodic table: d-block
CAS registry ID: 7440-25-7
Tantalum is a greyish silver, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which can be used as a filament for evaporating metals such as aluminium. 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 sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium.