Structural studies of matrix-isolated alkali-metal perchlorates: proof of a bidentate interaction

Abstract

The vapours from heated alkali-metal perchlorates isolated in nitrogen matrices have been studied by i.r. spectroscopy. The use of ¹⁸O/¹⁶O isotopic substitution demonstrates the presence of two distinct pairs of oxygen atoms for the RbClO₄ molecule isolated in a nitrogen matrix. Similar results were obtained for the caesium salt. This bidentate interaction between the ‘tetrahedral’ ClO₄^– ion and the Rb⁺(or Cs⁺) ion contrasts sharply with the tridentate interaction found previously between the pyramidal ClO₃^– ion and Cs⁺.