Editing Metallic bonding (section)

==Metallic radius==
The metallic radius is defined as one-half of the distance between the two adjacent metal ions in the metallic structure. This radius depends on the nature of the atom as well as its environment—specifically, on the [[coordination number]] (CN), which in turn depends on the temperature and applied pressure.

When comparing periodic trends in the size of atoms it is often desirable to apply the so-called Goldschmidt correction, which converts atomic radii to the values the atoms would have if they were 12-coordinated. Since metallic radii are largest for the highest coordination number, correction for less dense coordinations involves multiplying by {{mvar|x}}, where 0 < {{mvar|x}} < 1. Specifically, for CN = 4, {{mvar|x}} = 0.88; for CN = 6, {{mvar|x}} = 0.96, and for CN = 8, {{mvar|x}} = 0.97. The correction is named after [[Victor Goldschmidt]] who obtained the numerical values quoted above.<ref>{{cite book|title=Shriver and Atkins' Inorganic Chemistry|url=https://books.google.com/books?id=tUmcAQAAQBAJ&pg=PA74|year=2010|publisher=Oxford University Press|isbn=978-0-19-923617-6|pages=74–}}</ref>

The radii follow general [[periodic trends]]: they decrease across the period due to the increase in the [[effective nuclear charge]], which is not offset by the increased number of [[valence electrons]]; but the radii increase down the group due to an increase in the [[principal quantum number]]. Between the 4'''d''' and 5'''d''' elements, the [[lanthanide contraction]] is observed—there is very little increase of the radius down the group due to the presence of poorly [[electron shielding|shielding]] [[atomic orbitals|'''f''' orbitals]].