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as long as the ligand anisotropy is large. Hence, it is anticipated that ligands such as tropolone or 1,3-diphenylpropanedione should serve as excellent structural probes and that light scattering studies of such complexes should yield valuable structural information. This tool appears to be an especially attractive means with which to probe the structures of labile systems in solution. Many such structures are difficult or impossible to study effectively by other means. For example, it should be relatively simple to determine the amounts of cis and trans isomers present in solution for octahedral complexes of the general type dialkylbis( 1,3-diphenylpropanedionato)tin(IV), even though most NMR studies of such systems to date have been hampered by problems associated with very rapid rates of ligand exchange. It is anticipated that the structures of ion pairs can be studied in a similar fashion.
(4) D. J. Coumou, E. L. Mackor, and J. Hijmans, Trans. Faraday Soc,, 80, 1538 (1964). (5) D. J. Coumou, Trans. Faraday Soc., 85, 2654 (1969). (6) A. Gaglani, N. Asting, and W. H. Nelson, Inorg. Chem., 13, 1715 (1974). (7) W. R. Russo and W. H. Nelson, J. Am C h m Soc,92,1521 (1970). (8) K. G. Denbigh, Trans. Faraday Soc.,38, 936 (1940). (9) R. S. Smith and E. Mortensen, J. Chem. Phys., 32, 503 (1960). (10) E. R. Lippincott and J. M. Stutman, J. Phys. Chem, 68, 2926 (1964). (11) T. V. Long and R. A. Plane, J. Chem. Phys., 43, 457 (1965). (12) W. H. Nelson, J. Phys. Chem., 78, 1502 (1972). (13) H. S. Gabelnick and H.J. Strauss, J. Chem. Phys., 54,3846 (1971). (14) G. R. Alms, T. D. Gierke, and W. H. Fiygare, J. Chem. Phys., 81, 2083 (1974). (15) R. Pecora and W. A. Steele, J. Chem. Phys., 42, 1872 (1965). (16) J. Kielich, J. Chem. Phys., 48, 4090 (1967). (17) M. Mahnberg and E. R. Lippincott, J Cu//oki Interface Scl, 27, 591 (1968). (18) A. K. Burnham, G. R. Alms, and W. H. Flygare, J. Chem. Phys., 62, 3289 (1975). (19) M. J. Aroney, R. J. W. LeFevre, and J. D. Saxby, Aust. J. Chem., 18, 1501 (1965). (20) W. R. Russo and W. H. Nelson, J. Am. Chem. Soc., 92,455 (1970). (21) N. Asting, A. Gaglani, and W. H. Nelson, J. Co//o/dInterface Sci, 45, 170 (1973). (22) 6. Dzhuraev, V. I. Elfimov, and M. F. Vcks, Vestn. Leningr. Unlv., Fiz., Khim., 141 (1972). (23) K. H. Myer, Berichte, 47, 826 (1914). (24) L. W. Reeves, Can. J. Chem., 35, 1351 (1957). (25) J. R. LaLanne and P. Bothorel, Mol. Phys., 19, 227 (1970).
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Infrared Spectroscopic Evidence for Matrix-Isolated SF6James E. Barefield, 11, and Willlam A. Guillory" Department of Chemistfy, University of Utah, Salt Lake City, Utah 841 12 (Received September 13, 1978) Publication costs assisted by the National Science Foundation
A new absorption at 594 cm-', generated by charge transfer processes involving the photoionization of NO, Na, and K in the presence of matrix-isolated SF6,has been tentatively assigned to the SFC ion. This absorption was also observed to result from the photolysis of SF6 with the 1048- and 1066-Aresonance lines of argon. Attempts to generate this feature by electron impact and crossing a beam of metastable argon atoms with a SF6beam were unsuccessful.
Introduction Sulfur hexafluoride, having Oh symmetry, has a ground state electronic term 'Alr The ground state electronic configuration of SF6is a?,tfue4;hence, the ground state of SF, is expected to be a dougblet with the configuration aygt7ueia:g, and the corresponding term is 'A1,. A great deal of effort has been devoted to the study of SFC. The rate of attachment of thermal electrons to SF6has been studied by Hickam and Fox.' Compton et al. studied the nondissociative attachment of electrons to SF6.' According to this study, the nondissociative attachment of electrons to SF6 produces a long-lived SFC ion. The long lifetime was accounted for by assuming equipartitioning of energy among the vibrational modes of the SF6-ion. Electron transfer from excited Rydberg states of rare gas atoms to SF6 has been theoretically predicted by Matsuzawa to proceed with a large cross s e ~ t i o n . ~This theoretical prediction has been experimentally confirmed by Hotop and N i e h a ~ s . ~ Very little is known about the molecular structure of SFC. According to the xY6 Walsh diagram: the addition of an electron to the next highest totally symmetric MO (alg) of SF6retains the Oh symmetry, but would be expected to reduce the average S-F bond energy. Depending The Journal of Physlcal Chemlstru, Vol 8 1, No. 7, 1977
upon the extent of this reduction in S-F bond energy, one would expect to observe two red-shifted infrared active vibrational frequencies due to SF
