Adequate representation of charge polarization effects leads to a successful treatment of the CF4 + SiCl4 → CCl4 + SiF4 reaction by density functional theory.

Adequate polarization functions reduce the error of density functional theory (DFT) for the heat of reaction for CF(4) + SiCl(4) from ∼9-12 kcal mol(-1) to ∼2-4 kcal mol(-1), and using an improved density functional further reduces it to ∼1 kcal mol(-1). This reaction was previously identified as a stumbling block for DFT, but we show that the problem with the previous calculations was not DFT but rather inadequate basis sets to account for intramolecular charge polarization.