occur for weak multiple bonds, if the differences of the ligand are larger than the differences of R in the data used. Note that elements up to atomic number 118 (oganesson) have now been experimentally produced and that there are chemical studies on an increasing number of them. The same, self-consistent approach was used to fit tetrahedral covalent radii for 30 elements in 48 crystals with subpicometer accuracy. See also Atomic radii of the elements (data page) Ionization energy Electron affinity Electron configuration Periodic table References Chemical properties Chemical bonding Atomic radius