Gas-phase reactions of SF6 were investigated with 46 different atomic metal and main group cations at room temperature using an Inductively-Coupled Plasma/Selected-Ion Flow Tube (ICP/SIFT) tandem mass spectrometer. The atomic ions were produced at about 5500 K in the ICP source and allowed to decay radiatively and to thermalize by collisions with argon and helium atoms prior to reaction downstream in a flow tube in helium buffer gas at 0.35 +/- 0.01 Torr and 295 +/- 2 K. Rate coefficients and product distributions were measured for the reactions of fourth-row atomic ions from K+ to Se+, of fifth-row atomic ions from Rb+ to Te+ (excluding Tc+), and of sixth-row atomic ions from Cs+ to Bi+. The early transition metal ions react with SF6 very efficiently (k/k(c) = 0.56-0.96) to produce MFm+ (m = 1 -4) and SFn+ (n = 1-4) ions, whereas the late transition metal ions react much less efficiently (k/k(c) < 0.2) to form M+(SF6) adduct ions. Reactions of SF6 with Ca+, Sr+, Ba+, Ge+, and As+ proceed efficiently (k/k(c) = 0.35-0.85) through various channels, while all other main group metal ions are inert toward sulfur hexafluoride. Primary and seconday adduct formation was observed to exhibit equilibrium kinetics, and the standard free energy change for SF6 addition,is found to correlate with the efficiency of addition according to log[k/k(c)] = -8.7 + 7.8 log[-triangle G degrees/(kcal mol(-1))]. Several MFm+ ions were observed to react further with SF6 to produce MFm+k+, SFn+, and MFm+(SF6) as secondary products.