THE CRYSTAL STRUCTURE OF O₂⁺RuF₆^- AND THE NATURE OF O₂RhF₆

Philippe Botkovitz^a, George M. Lucier^a, Ramesh P. Rao^b, and Neil Bartlett^a*

^aDepartment of Chemistry, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, U.S.A., and ^bDepartment of Chemistry The University of British Columbia, Vancouver, B.C.,V6T 121, Canada

Abstract

The 146*K X-ray structure of an O2+RuF6- single crystal {cubic: a = 9.9125(15) A, V = 974.0(4) A3 Z = 8, space group Ia3} obtained from a liquid anhydrous HF (aHF) solution has proved the previously conjectured three-fold disorder of the O2+ species and gives interatomic distances O-O = 1.125(17) and RuF = 1.851(2) A. Interaction of RhF6 with O2 in aHF at * 20 *C, gives a red-brown cubic solid having a similar X-ray powder pattern (XRDP) to that of O2+RuF6- but, contrary to expectation for O2+RhF6-, it has a larger cell, with a = 10.17(1) A, V = 1052(3) A3, Z = 8. NO+RhF6- is rhombohedral with a = 5.046(5) A, * = 97.8(5) * , V = 124.6(4) A3 and isostructural with NO+AuF6-, and O2+AuF6-,the latter having smaller formula unit volume than the former. This suggests that the charge transfer in O2RhF6 is less complete than in O2+RuF6-.and that the electron affinity of RhF6 may be less than that of RuF6.