Molybdenum

Molybdenum is a chemical element with the symbol Mo and atomic number 42. 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.

What the numbers say

At standard temperature and pressure Molybdenum is a solid, sitting in period 5, group 6 of the d-block.

Its melting point of 2896 K (2623 °C) is the 6th highest of the 110 elements with a measured value — one of the most refractory elements there is.

At 10.28 g/cm³ it is the 26th densest of 96 elements with a quoted density.

Pauling electronegativity is 2.16. Paired with oxygen (3.44) that is a difference of 1.28, which puts the bond polar covalent — oxides here tend to be semiconducting or refractory rather than salt-like.

In the solid state it takes a body-centered cubic structure — BCC packing is stronger but shows a ductile-to-brittle transition as temperature drops.

It is reported in 8 oxidation states (-2, -1, 1, 2, 3, 4, 5, 6), which sets how many distinct compounds and phases it can form.

First identified in 1781.

Crystal structure

Check it against computed structures

The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Mo — with DFT formation energy, hull stability and band gap where the provider publishes them.