Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin molybdaenum, which is based on Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores.[6] Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.[7] Molybdenum does not occur naturally as a free metal on Earth; it is found only in various oxidation states in minerals. The free element, a silvery metal with a grey cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of the world production of the element (about 80%) is used in steel alloys, including high-strength alloys and superalloys. Most molybdenum compounds have low solubility in water, but when molybdenum-bearing minerals contact oxygen and water, the resulting molybdate ion MoO2− 4 is quite soluble. Industrially, molybdenum compounds (about 14% of world production of the element) are used in high-pressure and high-temperature applications as pigments and catalysts. Molybdenum-bearing enzymes are by far the most common bacterial catalysts for breaking the chemical bond in atmospheric molecular nitrogen in the process of biological nitrogen fixation. At least 50 molybdenum enzymes are now known in bacteria, plants, and animals, although only bacterial and cyanobacterial enzymes are involved in nitrogen fixation. These nitrogenases contain an iron-molybdenum cofactor FeMoco, which is believed to contain either Mo(III) or Mo(IV).[8][9] This is distinct from the fully oxidized Mo(VI) found complexed with molybdopterin in all other molybdenum-bearing enzymes, which perform a variety of crucial functions.[10] The variety of crucial reactions catalyzed by these latter enzymes means that molybdenum is an essential element for all higher eukaryote organisms, including humans.
Elven gymyk yw molybdenom, niver 42 y'n Vosen Beriodek. Y furvell gymyk yw Mo. An hanow a dheu dhyworth an ger Greka molybdos, o styrya plomm. Moon molybdenom, molybdenit y hanow, yw hevel y semlant dhe grafyt, ha kemyskys o an dhew gans moon plomm. Essensek yw molybdenom dhe bub eghen byw, mes yn mynsow munys. Re volybdenom a wra kawsya difasyansow kynfloghel. Yma a-dro dhe ugans ensaym ow komprendya molybdenom. Nitrogenas, kevys yn gwreydh fav, a dreyl nitrojen dhyworth an ayr dhe ammonya. Algi a wra devnydh a ensaym molybdenom dh'aga hartha dhyworth sulfur. An ensaym a'y dreyl dhe dimethyl sulfid, an gass hag drefen y fler a denn ydhyn an mor dhe rannow le mayth yw meur a algi hag awos hemma, meur a buskes. Ensaym enevales, xanthin oksidas, a askorr trenken urik, ha pan vo'n ensaym ma re weythresek, hemm a wra ledya dhe'n kudyn gowt. Usys yw an isotop radyoweythresek molybdenom-99 yn klavjiow dhe wul teknetiom-99. Teknetiom-99 a greun yn organow an korf, gans gweres diagnosans. Diskudhys veu molybdenom rag an kynsa prys gans Karl Scheele yn 1778, mes an kynsa dh'y enyshe veu Peter Jacob Hjelm (1746-1813) yn Uppsala, Sweden yn 1781. Usys o dur molybdenom dhe wul tankow yn Kynsa Bresel an Bys drefen y vos krev ha skav. Askorrys yw a-dro dhe 250,000 tonnas an vledhen, dre vras y'n Statys Unys, Chile, Kanada ha Russi. An chif moon yw molybdenit. Awos y boynt teudhi ughel, nyns yw askorrys avel alkan, mes avel polter loos dell yw usys. Usys yw lemmyn dhe wul daffar elektonek ha tredanel, dhe wul gweder, ha dhe wul dur-moly, dhe les yn kesrannow kerri ha jynnow ebron. Poos atomek molybdenom yw 95.94, y boynt teudhi yw 2617°C ha'y boynt bryjyon yw 4612°C. Y dhosedh yw 10.2kg an liter. Alkan lentrus arghansek yw ev, nebes medhel pan vo pur.langbot langbot