CHEMISTRY GLOSSARY

vanadium    →   vanadij

Vanadium was discovered by A. M. del Rio (Spain) in 1801 and rediscovered by Nils Sefstrom (Sweden) in 1830. Named after Vanadis, the goddess of beauty in Scandinavian mythology. It is soft, ductile, silvery-white metal. Resistant to corrosion by moisture, air and most acids and alkalis at room temperature. Exposed surfaces form oxide coating. Reacts with concentrated acids. Vanadium is found in the minerals patronite (VS₄), vanadinite [Pb₅(VO₄)₃Cl] and carnotite [K₂(UO₂)₂(VO₄)₂·3H₂O]. Pure metal produced by heating with C and Cl to produce VCl₃ which is heated with Mg in Ar atmosphere. It is mixed with other metals to make very strong and durable alloys. Vanadium pentoxide (V₂O₅) is used as a catalyst, dye and fixer-fixer.

contact procedure    →   kontaktni postupak

Contact procedure is an industrial procedure used for the production of sulphuric acid, where a dry and clean sulphur dioxide and air go over a catalyst made of vanadium pentoxide at 450 °C by which sulphur trioxide is gained, then we add concentrated sulphuric acid by which we obtain smoking sulphuric acid which is now diluted to sulphuric acid.

transition metal    →   prijelazni element

This group of metals is distinguished from other metals not by their physical properties, but by their electronic structure. Transition metals are elements characterized by a partially filled d subshell. The First Transition Series comprises scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni) and copper (Cu). The Second and Third Transition Series include the lanthanides and actinides, respectively.

The transition metals are noted for their variability in oxidation state. Thus, manganese has two electrons in its outside shell and five electrons in the next shell down, and exhibits oxidation states of +1, +2, +3, +4, +5, +6, and +7.

They are also characterised by the fact that well into the series, going from left to right, the properties of the succeeding metals do not differ greatly from the preceding ones.