How do you measure ionic radii?

Question

Peyton Adams · Accepted Answer

Usually the unit cell dimensions of ionic solids are interrogated.......

To a first approximation, ionic solids are considered to be close-packed spherical cations, and anions.......And ionic radii can thus be determined from structural data.

The data here are quoted in #"picometre"#, #10^-12*m#. Structural chemists would more commonly use #"Angstroms"#, where #"1 Angstrom"-=1*stackrel(@)"A"=1xx10^-10*m#.

Given the data in the diagram, why should ANIONS be larger than same Period CATIONS? Certainly if we interrogated the atomic radii, those atoms to the right of the Period as we face it are SMALLER than the atoms to the left.

Noah Aldrich · Answer

undefined Ionic radii are typically measured using X-ray crystallography or by analyzing the distances between ions in ionic compounds. X-ray crystallography involves shooting X-rays at a crystal lattice and analyzing the diffraction patterns produced. By comparing these patterns to known structures, the distances between ions can be determined, allowing for the calculation of ionic radii. Alternatively, ionic radii can also be estimated using theoretical models or empirical data collected from various sources.