Combining Theory with Experiment: Assessment of the Thermochemistry of SFn, SFn+, and SFn-, n = 1-6

Abstract

The comparison of the experimental thermochemical data and G2 or [G2(MP2)] predictions for SF{sub n}, SF{sub n}{sup +}, and SF{sub n} {sup -} (n = 1-6) allows us to recommend a self-consistent set of experimental {Delta}{sub f}H{degree}{sub 0}, IE, EA, D{degree}{sub 0} values for these systems. This work shows that for reliable determinations of the thermochemical data for a complex system such as SF{sub n}, SF{sub n} {sup +}, and SF{sub n}{sup -} (n = 1-6), it is necessary to combine experimental measurements made using different techniques and theoretical predictions calculated using a sufficiently accurate theoretical procedure. The comparison of experimental and theoretical results in this study further confirms that G2 and G2(MP2) procedures are reliable theoretical methods for providing energetic predictions accurate to 4-5 kcal/mol for complex sulfur-containing molecular species. The theoretical equilibrium structures obtained for SF{sub n}, SF{sub n}{sup +}, and SF{sub n}{sup -} (n = 1-6) have been rationalized using the VSEPR theory. Furthermore, we have provided an explanation to account for the observed alternating patterns in IE, EA, and D{degree}{sub 0} values for SF{sub n}, SF{sub n}{sup +}, and SF{sub n}{sup -} (n = 1-6). Alternating patterns in IE, EA, and D{degree}{sub 0} values are expectedmore » for other similar hypervalent species. 60 refs., 2 figs., 4 tabs.« less