Electron Delocalization Caused in 3d Complexes by Azide and Chloride Ligands Checked by Positronium Spin-Exchange Reactions

The rate constants k _CR of orthointo para-positronium conversion reactions promoted by 3d complexes are linearly correlated with the electron delocalization of unpaired metal electrons caused by ligands, as measured by the ratio between the interelectronic repulsion parameters in complexes and in the free gaseous ions (1 > 0). The values may be evaluated by means of the following empirical equation: = 1 t _M h _L, where t _M and h _L are characteristic constants of 3d ions and ligands, respectively. By measuring k _CR and applying the correlations mentioned above, h _L constants may be derived providing that t _M is known. The method was used to measure the h _L value of N^– ₃, not yet known, and to check that of Cl^– ligand.