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I was reading about different types of atomic radius. It was written that if any atom can possess all the three types of radius, then van der Waals radius will be greater than metallic radius. However from the above diagram, it appears that the van der Waals radius and metallic radius are equal.
Then how can the van der Waals radius be greater than metallic radius?
Metallic radius is half of the distance between the nuclei of two atoms when they are in crystalline structure and bond is formed between positively charged atoms, that means they are tightly packed in metallic lattice.
And van der Waals radius is half of the internuclear distance of two non-bonded atoms of the same element in the closest possible distance.
Don't compare both the situations using above diagrams. The radii are calculated in two different situations.
As in case of metallic bond, the atoms are bonded tightly so their shells can overlap, but in case of van der wal forces the bond is weak. Therefore, in case of van der waal force, the internuclear distance will be higher as compared to metallic bond.
