On the accurate bond-valence parameters for the Sb³⁺/O²⁻ ion pair

The improved values of the bond-valence parameters for the Sb³⁺/O^2– ion pair, r₀ = 1.927 Å and b = 0.446 Å, have been deduced from the crystal structures of the α and β polymorphs of Sb₂O₃ and from the set of precisely determined complex structures containing [Sb³⁺O_n] coordination shells.