The Group 3B elements (called the inner transition metals in some periodic tables) are malleable and ductile, as well as good conductors of heat and electricity. They usually form 2+ and 3+ ions, but some form other oxidation states. Ruthenium is a silvery-gray, extremely brittle and stable metal that is used in electrical contact points and chip resistors. In addition, ruthenium is used in the enzyme that enables some species of bacteria to “fix” nitrogen from the atmosphere (reducing it to ammonia) in the production of food.
Nickel is a silvery-white metal that is very hard and ductile, but less magnetic than iron. It is found in the Earth’s crust at a concentration of 80 ppm, making it the 23rd most abundant element. Nickel is found in the ores millerite [nickel sulfide, NiS], pentlandite [(Fe,Ni)9S8], nickeline [nickel arsenide, NiAs], and garnierite [(Fe,Ni)3Si2O5(OH)].
Molybdenum is a lustrous, silvery-white metal that is very similar to lead. It is found in the ores molybdenite [molybdenum sulfide, MoS2], which looks like graphite, and wulfenite [lead molybdate, PbMoO4]. Molybdenum is used in alloys with iron to make springs, high-speed tools and surgical instruments, and gears and crankshafts, as well as in aircraft components and armor plating.
Vanadium is a brittle, metallic gray metal that is highly reactive and not as durable as the Group 3B metals. It is used in alloys with iron to make a tough, shock-resistant metal called ferrovanadium, which is also useful as a component of high-speed tools and surgical equipment. Traces of vanadium are also found in Damascus steel, and traces of it can be seen in the rust that forms on some iron surfaces.