Ionic radii (Shannon) for octahedral M(-II) ion

These are Shannon ionic radii.

Image showing periodicity of ionic radii (Shannon) for octahedral M(-II) ion for group 8 chemical elements.
Image showing periodicity of ionic radii (Shannon) for octahedral M(-II) ion for group 8 chemical elements.

Units

pm

Notes

The "effective ionic radii" quoted here assume that the ionic radius of F- is 133 pm and that of O2- is 140 pm.

Values depend upon the coordination number and for d-block metals whether or not the metal is in a high or low spin state.

Older "crystal ionic radii" are based upon a radius of six-coordinate F- = 119 pm and are 14-18% larger than effective ionic radii.

You can look at visual representations of the data for different coordination and oxidation numbers using the following links,

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