Revised radii of the univalent Cu, Ag, Au and Tl cations

Radii of Cu⁺, Ag⁺, Au⁺ and Tl⁺ cations are determined by the additive method from interatomic distances in molecular and/or crystalline halides, oxides, chalcogenides and cyanides with different coordinations of atoms, and then recalculated for the 6-coordination number. The averaged (from 74 structures) values of revised radii are equal to r(Cu⁺) = 0.74 Å, r(Ag⁺) = 0.99 Å, r(Au⁺) = 0.92 Å, r(Tl⁺) = 1.22 Å, which are consistent with radii calculated from direct cation–cation contacts in ultimately compressed metals.