Bond-valence sums for Tc-O systems from EXAFS data

Unit-valence parameters R0 were calculated for Tc-O bonds in Tc(VII)-Tc(III) compounds using data from X-ray crystal structures. A method was developed to estimate R0 values for given oxidation states and coordination numbers in order to verify the calculated values. The R0 values were used to evaluate bond distances and coordination numbers obtained from EXAFS models for several Tc compounds.