Explicitly correlated CCSD(T)-F12b calculations show that the lowest energy conformer of XeF6 is the C-3v structure with a stereoactive lone pair. The C-3v structure is 1.08 kcal/mol below the C-2v structure and 1.80 kcal/mol below the O-h structure without vibrational corrections. The C-2v conformer is a transition state connecting the different C-3v minima on the pseudorotation potential energy surface, and the Oh structure is a higher-order saddle point leading to the C-2v transition states. The calculated vibrational frequencies for the C-3v structure best fit the experimental frequencies. The calculated heats of formation for XeF6, -62.1 +/- 1.4 kcal/mol at 0 K and -64.0 +/- 1.4 kcal/mol at 298 K, are the best available values and show that there are serious issues with the experimental values. The results show that the explicitly correlated CCSD(T)-F12b method can be used to address important electronic structure issues with smaller basis sets.