The transition metals and their compounds have hugely varied uses, but general trends can be identified.
Generally possessed of strength and hardness, they are widely employed as construction materials, and their properties can be emphasized or tempered by inclusion in alloys. Their high melting and boiling points make them of use in instances where extreme temperatures must be withstood without loss of performance: jet engines, light bulb and heater filaments, thermocouples, nuclear reactors. Iron is the most extensively used of the transition elements, being the basis of innumerable steels. Such steels are used in cars, bicycles, cookers and many other items.
The metals are also of importance as catalysts. Vanadium pentoxide is used as a catalyst in the manufacture of sulphuric acid, and iron in the Haber process for the manufacture of ammonia. Platinum group metals such as platinum, rhodium and palladium, are especially efficient catalysts, their most familiar use being in the catalytic convertors attached to car exhausts.
The tendency of transition metals to form coloured compounds makes them of use in the manufacture of pigments. Cadmium yellow, chromium green, cobalt blue, zinc white and titanium white are all well known to artists.
