42
95.95
Mo
Molybdenum
Identification
CAS Number: 7439-98-7
Discovery Year: 1778
Discoverer: Carl Wilhelm Scheele
Discovery Location: Sweden
Properties
Atomic Dimensions
Atomic Radius: 145 pm →
Atomic Radius (Rahm): 244 pm
Covalent Radius: 154 pm →Van der Waals Radius: 217 pm
Metallic Radius: 130 pm
Atomic Volume: 9.4 cm³/mol
Lattice Constant: 3.15 Å
Thermodynamics
Electronic Structure
Electron Config: [Kr] 4d5 5s
Block: d
Period: 5 →Group: 6 →Electronegativity: 2.16 →Electron Affinity: 0.748 eV →Oxidation States: +2, +3, +4, +5, +6
Abundance & Geochemistry
Crust Abundance: 1.2 mg/kg
Sea Abundance: 0.01 mg/L
Goldschmidt Class: siderophile
About
Silvery-white, hard metallic transition element. It is chemically unreactive and is not affected by most acids. It oxidizes at high temperatures. There are seven natural isotopes, and four radioisotopes, Mo-93 being the most stable with a half-life of 3500 years. Molybdenum is used in almost all high-strength steels, it has nuclear applications, and is a catalyst in petroleum refining. Discovered in 1778 by Carl Welhelm Scheele of Sweden. Impure metal was prepared in 1782 by Peter Jacob Hjelm. The name comes from the Greek word molybdos which means lead. Trace amounts of molybdenum are required for all known forms of life. All molybdenum compounds should be considered highly toxic, and will also cause severe birth defects.
Isotopes
Mo-98 98 24.29%
Mo-96 96 16.67%
Mo-95 95 15.87%
Mo-92 92 14.65%
Mo-100 100 9.74%
Mo-97 97 9.58%
Mo-94 94 9.19%