Krypton

Krypton (from Ancient Greek: κρυπτός, romanized: kryptos 'the hidden one') is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps.

What the numbers say

At standard temperature and pressure Krypton is a gas, sitting in period 4, group 18 of the p-block.

Its melting point of 116 K (-157 °C) is the 103rd highest of the 110 elements with a measured value — among the lowest-melting elements.

At 0.004 g/cm³ it is the 88th densest of 96 elements with a quoted density.

Pauling electronegativity is 3. Paired with oxygen (3.44) that is a difference of 0.44, 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 face-centered cubic structure — FCC packing gives 12 independent slip systems, which is why FCC metals are the ductile, formable ones.

First identified in 1898.

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