A comment on “The interaction of X2 (X = F, Cl, and Br) with active sites of graphite” [Xu et al., Chem. Phys. Lett., 418, 413 (2006)]

•The chemisorption of the halogens F2, Cl2, and Br2 on the active sites of graphite is reevaluated.•Major differences are found with respect to Xu et al., Chem. Phys. Lett., 418, 413 (2006).•The order of adsorption strength is zigzag > armchair (symmetric) > armchair (asymmetric).•Xu et al.’s results have errors up to 600% and 42% for the zigzag and armchair surface, respectively.