Molybdenum (Mo) is a chemical element in the periodic table with atomic number 42, discovered by Carl Wilhelm Scheele in 1778. Its name is derived from the Greek word Molybdos which means lead. It is a silvery-white, hard transition metal and has one of the highest melting points of all pure elements.
Most molybdenum is used to make alloys. It is used in steel alloys to increase strength, hardness, electrical conductivity and resistance to corrosion and wear. These 'moly steel' alloys are used in parts of engines. Other alloys are used in heating elements, drills and saw blades.
Molybdenum metal is a dark-gray or black powder with a metallic luster (NLM 2020a). It is a transition element in Group 6 of the Periodic Table. It has oxidation states from −2 to +6. Commonly encountered compounds are those of molybdenum in oxidation state +6 (Mo(VI), MoO3, molybdates) and +4 (Mo(IV), MoS2).
Molybdenum's story begins with mistaken identity. The mineral containing molybdenum, molybdenite, was often confused with lead ore or graphite for centuries. It wasn't until 1778 that Swedish chemist Carl Wilhelm Scheele identified molybdenite as distinct and containing a potentially new element. However, isolating the element itself proved challenging.
Finally, in 1781, another Swedish chemist, Peter Jacob Hjelm, successfully isolated molybdenum using carbon and linseed oil. Despite this discovery, molybdenum remained largely unused for nearly a century due to its scarcity, difficulty in extraction, and limited understanding of its properties.