Group 5 of the Periodic Table

Group 5 is the fifth column of the periodic table, consisting of the elements vanadium (V), niobium (Nb), tantalum (Ta), and dubnium (Db). All are transition metals, meaning their valence electrons occupy partially filled d-orbitals. The group number reflects the fact that these elements can have five electrons available for chemical bonding, making an oxidation state of +5 common and stable.

Vanadium, niobium, and tantalum are hard metals with high melting points that resist corrosion because they form protective oxide layers on their surfaces. Dubnium is a synthetic, radioactive element that does not occur naturally in the Earth's crust; its short half-life restricts research into its chemical properties.

General Properties

Moving from vanadium to tantalum, density increases sharply—tantalum is significantly heavier than vanadium. Tantalum and niobium are closely similar in size and chemical character, which means they occur mixed together in nature (for example in the mineral columbite-tantalite), and separation is difficult. Vanadium exhibits multiple oxidation states (+2, +3, +4, +5), each producing a different color in aqueous solution, a property notable in redox chemistry.

Applications

Vanadium is chiefly used in steel alloys to increase strength and hardness; its oxides serve as industrial catalysts. Niobium is added to high-strength low-alloy (HSLA) steel and to superconducting alloys, particularly for high-strength wires. Tantalum is used in capacitors for electronic devices because of its oxide's high capacitance and stability, and in medical implants because it is compatible with body tissues.

Dubnium

Dubnium is element 105. It is produced by nuclear synthesis through the collision of heavy ions. Its name comes from Dubna, a nuclear research center. Because so few atoms are produced with such difficulty, knowledge of its chemistry rests largely on theory and limited experiment; however, it is expected to share some properties with tantalum.