Ruthenium

Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table.

What the numbers say

At standard temperature and pressure Ruthenium is a solid, sitting in period 5, group 8 of the d-block.

Its melting point of 2607 K (2334 °C) is the 9th highest of the 110 elements with a measured value — one of the most refractory elements there is.

At 12.37 g/cm³ it is the 19th densest of 96 elements with a quoted density.

Pauling electronegativity is 2.2. Paired with oxygen (3.44) that is a difference of 1.24, 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 simple hexagonal structure — hexagonal packing offers few easy slip systems, so properties are anisotropic and formability is limited.

It is reported in 9 oxidation states (-2, 1, 2, 3, 4, 5, 6, 7, 8), which sets how many distinct compounds and phases it can form.

First identified in 1844.

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 Ru — with DFT formation energy, hull stability and band gap where the provider publishes them.