How Was Molybdenum Discovered?
Molybdenum, symbol Mo, atomic number 42, melting point 2,623 degrees Celsius, occurs in various mineral ores that have long been known, such as Molybdenite (molybdenum sulfide), Wulfenite (lead molybdate) and Powellite (calcium molybdate). Although known as ores, it was not known that they contained the transition metal, molybdenum. It was not until 1778 that Karl Wilhelm Scheele (1742-1786), an apothecary in Koping, Sweden, made the discovery. The metal was first isolated in 1781 by Peter Jacob Hjelm (1746-1813). Previous Misconceptions Molybdenum sulfide is a soft, lubricating, black solid that makes a mark on paper. For this reason, it was mistakenly felt to be an ore of lead. The Greek word “molybdos” means lead, but was also applied to graphite and (unwittingly) to molybdenum sulfide. Lead was once used to make pencils. Later, graphite replaced the lead in pencils. Interestingly, graphite, like molybdenum sulfide, is used as a solid lubricant. Lead in brass also adds lubricity to
