Atomic number:42

Group numbers:6

Period:5

Electronic configuration:[Kr] 4d⁵ 5s¹

Formal oxidation number:+6

Electronegativities:2.16

Atomic radius / pm:136.3

Relative atomic mass:95.94 ± 0.02

 

Molybdenum was discovered by Carl William Scheele (SE) in 1778. The origin of the name comes from the Greek word molybdos meaning lead. It is a silvery white, very hard metal, but is softer and more ductile than tungsten. Molybdenum is found in the minerals molybdenite (MoS2) and wulfenite (MoO4Pb). Its alloys are used in aircraft, missiles and protective coatings in boiler plate.

Density / g dm^-3:10220 (293 K)

 9330 (m.p.)

Molar volume / cm³mol^-1:9.39 (293 K)

 10.28 (m.p.)

Electrical resistivity / μΩcm:5.34 (20 °C)

Thermal conductivity / W m^-1K^-1:138

Melting point / °C:2623

Boiling point / °C:4639

Heat of fusion / kJ mol^-1:27.6

Heat of vaporization / kJ mol^-1:589.9

Heat of atomization / kJ mol^-1:656.55

1st ionization energy / kJ mol^-1:684.32

2nd ionization energy / kJ mol^-1:1559.21

3rd ionization energy / kJ mol^-1:2617.67

in the atmosphere / ppm:-

in the Earth's crust / ppm:1

in the oceans / ppm:0.01