Welcome to Chem Zipper.com......: Metallic radius or Crystal radius:

Search This Blog

Thursday, August 5, 2021

Metallic radius or Crystal radius:

Metallic radius or Crystal radius:

(1) The term crystal radius is used to denote the size of atoms in metal.

(2) Metal atoms are closely packed spheres in metallic crystal. The metal atoms are supposed to touch one another in crystal.

(3) Metallic radius is defined as one half the distances between the centres of the nuclei of two atoms in a metallic crystal.

(4) Metallic radius is determined by X-ray diffraction method.

(5) Metallic radii are about 10 to 15 % higher than the single bond covalent raddi of those elements. Thus single bond covalent radius is smaller than the metallic radius due to the no overlapping of atomic orbital in metallic bond.

Vander Waal’s radius > Metallic radius > Covalent radius

(6) For the simplicity the term atomic radius is used for covalent radius as well as metallic radius depending on whether the element is a non-metal or metal. However, the atomic radii of inert gases are expressed in the terms of Vander Waal’s radii.

(7) Metallic radius is inversely proportional to the metallic bond strength.

(8) More metallic radius –loose crystal packing-less bond strength. (BCC)

(9) Less metallic radius –Tight crystal packing (FCC) - high bond strength.(HCP)

(10) For non-metal, atomic radius means covalent radius.

(11) For metal, atomic radius means metallic radius.

(12) For inert gases, atomic radius means Vander Waal’s radius.

Vander Waal’s radius or Collision radius:

Related Questions:

(1) What are the Amphoteric metals ? gives Examples.

No comments:

Post a Comment